Lewis
How many pins and in what packaging profile…also are there any other chips used in the unit…other that its power supply regulator …what brand and model of GDO also….Genie, Chamberlain, Overhead Door ?
All I find is a large 80 pin u/p under that series of numberings cross referencing…..and I’m sure that’s not it.
73's de Edd
You can try prefix-ing that # with the mfrs name or if there is a mfrs logo TI/Mot etc on the chip use that as a prefix, and Google it. Neighbor just gave me a faulty opener with 2 remotes. I checked the remotes (Chamberlain), but that # is not on any IC chips.
marv
:Off subject, I know but I'm desperate! Does anyone know where I can get a datasheet for a 051-8728 garage opener IC chip? What I hate about modern stuff. No idea how it works, what it is, etc, etc. I can figure out a tube type radio without a schematic most of the time, but not modern junk!!
:Lewis
:
:You can try prefix-ing that # with the mfrs name or if there is a mfrs logo TI/Mot etc on the chip use that as a prefix, and Google it. Neighbor just gave me a faulty opener with 2 remotes. I checked the remotes (Chamberlain), but that # is not on any IC chips.
:
:marv
All:
Axually, this is part of a door opener that a friend of mine who is the maintenance man for our local library is trying to fix. The chip is an 18 pin DIP, connected in part to a 10 DIP switch, and a few other components, including one transistor, but no coils. He is pretty nervous, because without this they are in violation of the Americans With Disabilities Act. The thing was obviously modified from a garage door opener, you can see where there were holes drilled for a push button.
Lewis
:
::Off subject, I know but I'm desperate! Does anyone know where I can get a datasheet for a 051-8728 garage opener IC chip? What I hate about modern stuff. No idea how it works, what it is, etc, etc. I can figure out a tube type radio without a schematic most of the time, but not modern junk!!
::Lewis
::
::You can try prefix-ing that # with the mfrs name or if there is a mfrs logo TI/Mot etc on the chip use that as a prefix, and Google it. Neighbor just gave me a faulty opener with 2 remotes. I checked the remotes (Chamberlain), but that # is not on any IC chips.
::
::marv
:
:All:
:Axually, this is part of a door opener that a friend of mine who is the maintenance man for our local library is trying to fix. The chip is an 18 pin DIP, connected in part to a 10 DIP switch, and a few other components, including one transistor, but no coils. He is pretty nervous, because without this they are in violation of the Americans With Disabilities Act. The thing was obviously modified from a garage door opener, you can see where there were holes drilled for a push button.
:Lewis
Oh and P. S. the thing was made by Semefab, shoever they are.
LL
:
:
:
:
:
::
:::Off subject, I know but I'm desperate! Does anyone know where I can get a datasheet for a 051-8728 garage opener IC chip? What I hate about modern stuff. No idea how it works, what it is, etc, etc. I can figure out a tube type radio without a schematic most of the time, but not modern junk!!
:::Lewis
:::
So by your description, it is the receiver part, not the remote (transmitter) and modified to work with a pusbutton vs an RF link/decoder.
marv
:::Lewis,
:::You can try prefix-ing that # with the mfrs name or if there is a mfrs logo TI/Mot etc on the chip use that as a prefix, and Google it. Neighbor just gave me a faulty opener with 2 remotes. I checked the remotes (Chamberlain), but that # is not on any IC chips.
:::
:::marv
::
::All:
::Axually, this is part of a door opener that a friend of mine who is the maintenance man for our local library is trying to fix. The chip is an 18 pin DIP, connected in part to a 10 DIP switch, and a few other components, including one transistor, but no coils. He is pretty nervous, because without this they are in violation of the Americans With Disabilities Act. The thing was obviously modified from a garage door opener, you can see where there were holes drilled for a push button.
::Lewis
:
:Oh and P. S. the thing was made by Semefab, shoever they are.
:LL
::
::
::
::
::
:::
::::Off subject, I know but I'm desperate! Does anyone know where I can get a datasheet for a 051-8728 garage opener IC chip? What I hate about modern stuff. No idea how it works, what it is, etc, etc. I can figure out a tube type radio without a schematic most of the time, but not modern junk!!
::::Lewis
::::
:So by your description, it is the receiver part, not the remote (transmitter) and modified to work with a pusbutton vs an RF link/decoder.
:
:marv
I took the door apart, the reciever is obviously something added (for ADA?). The door is a power assisted thing, meaning when you push the handle, it goes ahead and opens fulll, waits a few seconds, and closes. It looks like to me that a reciever was added, wires soldered to screw terminals, and stands put up where wheelchair victims could pust a disk, operating a microswitch is connected where the push button switch used to be when this thing was in a plastic case.
:
::::Lewis,
::::You can try prefix-ing that # with the mfrs name or if there is a mfrs logo TI/Mot etc on the chip use that as a prefix, and Google it. Neighbor just gave me a faulty opener with 2 remotes. I checked the remotes (Chamberlain), but that # is not on any IC chips.
::::
::::marv
:::
:::All:
:::Axually, this is part of a door opener that a friend of mine who is the maintenance man for our local library is trying to fix. The chip is an 18 pin DIP, connected in part to a 10 DIP switch, and a few other components, including one transistor, but no coils. He is pretty nervous, because without this they are in violation of the Americans With Disabilities Act. The thing was obviously modified from a garage door opener, you can see where there were holes drilled for a push button.
:::Lewis
::
::Oh and P. S. the thing was made by Semefab, shoever they are.
::LL
:::
:::
:::
:::
:::
::::
:::::Off subject, I know but I'm desperate! Does anyone know where I can get a datasheet for a 051-8728 garage opener IC chip? What I hate about modern stuff. No idea how it works, what it is, etc, etc. I can figure out a tube type radio without a schematic most of the time, but not modern junk!!
:::::Lewis
:::::
Saw several references as an 8 bit micro with PLL, freq synthesizer used in AM/FM radios, when I Googled it. If that is accurate, there may not be any coils etc on the board, because its all done digitally. Older GDO's had a wall box with RF receiver and just 2 wires going to the motor/transmission assembly, but newer ones have the receiver in the same box as the motor/transmission, and still have a wall box with just switches and 2 wires.
marv
::Lewis,
::So by your description, it is the receiver part, not the remote (transmitter) and modified to work with a pusbutton vs an RF link/decoder.
::
::marv
:I took the door apart, the reciever is obviously something added (for ADA?). The door is a power assisted thing, meaning when you push the handle, it goes ahead and opens fulll, waits a few seconds, and closes. It looks like to me that a reciever was added, wires soldered to screw terminals, and stands put up where wheelchair victims could pust a disk, operating a microswitch is connected where the push button switch used to be when this thing was in a plastic case.
::
:::::Lewis,
:::::You can try prefix-ing that # with the mfrs name or if there is a mfrs logo TI/Mot etc on the chip use that as a prefix, and Google it. Neighbor just gave me a faulty opener with 2 remotes. I checked the remotes (Chamberlain), but that # is not on any IC chips.
:::::
:::::marv
::::
::::All:
::::Axually, this is part of a door opener that a friend of mine who is the maintenance man for our local library is trying to fix. The chip is an 18 pin DIP, connected in part to a 10 DIP switch, and a few other components, including one transistor, but no coils. He is pretty nervous, because without this they are in violation of the Americans With Disabilities Act. The thing was obviously modified from a garage door opener, you can see where there were holes drilled for a push button.
::::Lewis
:::
:::Oh and P. S. the thing was made by Semefab, shoever they are.
:::LL
::::
::::
::::
::::
::::
:::::
::::::Off subject, I know but I'm desperate! Does anyone know where I can get a datasheet for a 051-8728 garage opener IC chip? What I hate about modern stuff. No idea how it works, what it is, etc, etc. I can figure out a tube type radio without a schematic most of the time, but not modern junk!!
::::::Lewis
::::::
:Saw several references as an 8 bit micro with PLL, freq synthesizer used in AM/FM radios, when I Googled it. If that is accurate, there may not be any coils etc on the board, because its all done digitally. Older GDO's had a wall box with RF receiver and just 2 wires going to the motor/transmission assembly, but newer ones have the receiver in the same box as the motor/transmission, and still have a wall box with just switches and 2 wires.
marv
Marv:
Could you give me a link to the 8=bit/PLL device you mention? It would sure be nice if I had some idea of what I am doing!!! I think you are right about the PLL as there are some resistors in parallel with a capacitor, and two of the resistors have been clipped off the board, as if someone were tuning a PLL.
Lewis
:
Don't remember the link. Just Google Semefab 051-8728, and you'll get sites. Then go from there. I didn't find full-blown data sheets, just single sheet descriptions, but didn't scroll thru all listed sites either or I'd still be there.
marv
::Lewis,
::Saw several references as an 8 bit micro with PLL, freq synthesizer used in AM/FM radios, when I Googled it. If that is accurate, there may not be any coils etc on the board, because its all done digitally. Older GDO's had a wall box with RF receiver and just 2 wires going to the motor/transmission assembly, but newer ones have the receiver in the same box as the motor/transmission, and still have a wall box with just switches and 2 wires.
:marv
:
:
:
:Marv:
:Could you give me a link to the 8=bit/PLL device you mention? It would sure be nice if I had some idea of what I am doing!!! I think you are right about the PLL as there are some resistors in parallel with a capacitor, and two of the resistors have been clipped off the board, as if someone were tuning a PLL.
:Lewis
::
We use radio transmitters/receivers for some of the systems we install and it may be less expensive to buy a transmitter/receiver pair and replace it if all you need is a remotely operated contact closure. Some of the places we buy from are ADI and Multi-Sales and we've used both the Linear and MultiElmac line.
::Lewis,
::You can try prefix-ing that # with the mfrs name or if there is a mfrs logo TI/Mot etc on the chip use that as a prefix, and Google it. Neighbor just gave me a faulty opener with 2 remotes. I checked the remotes (Chamberlain), but that # is not on any IC chips.
::
::marv
:
:All:
:Axually, this is part of a door opener that a friend of mine who is the maintenance man for our local library is trying to fix. The chip is an 18 pin DIP, connected in part to a 10 DIP switch, and a few other components, including one transistor, but no coils. He is pretty nervous, because without this they are in violation of the Americans With Disabilities Act. The thing was obviously modified from a garage door opener, you can see where there were holes drilled for a push button.
:Lewis
:
:
:
:
:
::
:::Off subject, I know but I'm desperate! Does anyone know where I can get a datasheet for a 051-8728 garage opener IC chip? What I hate about modern stuff. No idea how it works, what it is, etc, etc. I can figure out a tube type radio without a schematic most of the time, but not modern junk!!
:::Lewis
:::
:
:We use radio transmitters/receivers for some of the systems we install and it may be less expensive to buy a transmitter/receiver pair and replace it if all you need is a remotely operated contact closure. Some of the places we buy from are ADI and Multi-Sales and we've used both the Linear and MultiElmac line.
I think I might have found a crack in the PWB. Also, there are a good number of "Universal garage door openers" that are pretty cheap. (Does this mean they will open garage doors on Pluto?) Anyway, I am a little less antsy about this thing than I was earlier.
I don't know why the **** they didn't just run thirty feet of wire from the microswitch to the door controller, I guess the concrete had already been poured and this was the easiest way. Anyway, I'm going over to the library and check out my latest "repair" tomorrow.
Thanx, all,
Lewis
Lewis
:
:::Lewis,
:::You can try prefix-ing that # with the mfrs name or if there is a mfrs logo TI/Mot etc on the chip use that as a prefix, and Google it. Neighbor just gave me a faulty opener with 2 remotes. I checked the remotes (Chamberlain), but that # is not on any IC chips.
:::
:::marv
::
::All:
::Axually, this is part of a door opener that a friend of mine who is the maintenance man for our local library is trying to fix. The chip is an 18 pin DIP, connected in part to a 10 DIP switch, and a few other components, including one transistor, but no coils. He is pretty nervous, because without this they are in violation of the Americans With Disabilities Act. The thing was obviously modified from a garage door opener, you can see where there were holes drilled for a push button.
::Lewis
::
::
::
::
::
:::
::::Off subject, I know but I'm desperate! Does anyone know where I can get a datasheet for a 051-8728 garage opener IC chip? What I hate about modern stuff. No idea how it works, what it is, etc, etc. I can figure out a tube type radio without a schematic most of the time, but not modern junk!!
::::Lewis
::::
After detection of the signal back to an audio element there should be a stage of amplification and then some shaping before It is possible to loosely couple into the output of the receiver audio with an ~ .001 ufd capacitor and then feed into a signal tracer / audio amplifier and actually hear the incoming xmitted signal to confirm that the receiver is receiving the tonal digital burst of signal from the xmitter, (chirp) thus confirming that the xmitter is putting out, coded, and the receiver tuning and performance is good to that AF point.
Sir Lewis.....
Ahhhhh Sooooo….seems like with more info coming forth…more info can be fed back to you.
Sounds like that unit might be a late 80’s possibly on into the early ‘90’s vintage…and with that pin count out …on a DIP…
I feel that your “mystery chip” is the digital decoder chip of the receiver for the code stream that is sent via the RF of the xmitter.Look for a companion in the xmitter unit
I feel sure that the RF aspect is probably the common 1 xstr superregenerative receiver, incorporated since day one of the transistorization of units . Look at the board closely where the antenna connection comes in and the closest discrete xstr nearby should be that unit. That is also confirmable by the very old generation technique of a hairpin loop of very heavy wire being used as its inductive element of its tuned LC network of the receiver. However, real soon afterwards the inductor was formed stripline as an etched inductor on the PCB foil path…totally plausible at the higher assigned RF frequencies incorporated by GDO’s..
the feeding into that decoder chip to confirm authentication of the xmitted series digital stream...that is why the dip switches are nearby and tied into that unit, confirm that the xmit unit is set up the same way (code)…thank goodness that you are not up against any of the newer units with an infinitely more complex rollover coding technique used.
WITHOUT an incoming signal, one should hear the omnipresent white noise hiss of a superregen receiver…easy to utilize when you are initially probing for locating that point in the receiver where audio is, or it will also be found at a pin of the decoder chip.
If you could provide a closeup pic of both sides of the board…...more help could be forthcoming. Also some code dates on parts would be helpful in the dating of that unit.
73's de Edd
:
:
:
:
:
:
:Sir Lewis.....
:
:
:Ahhhhh Sooooo….seems like with more info coming forth…more info can be fed back to you.
:
:
:Sounds like that unit might be a late 80’s possibly on into the early ‘90’s vintage…and with that pin count out …on a DIP…
: I feel that your “mystery chip” is the digital decoder chip of the receiver for the code stream that is sent via the RF of the xmitter.Look for a companion in the xmitter unit
:
:I feel sure that the RF aspect is probably the common 1 xstr superregenerative receiver, incorporated since day one of the transistorization of units . Look at the board closely where the antenna connection comes in and the closest discrete xstr nearby should be that unit. That is also confirmable by the very old generation technique of a hairpin loop of very heavy wire being used as its inductive element of its tuned LC network of the receiver. However, real soon afterwards the inductor was formed stripline as an etched inductor on the PCB foil path…totally plausible at the higher assigned RF frequencies incorporated by GDO’s..
:
:
:
:After detection of the signal back to an audio element there should be a stage of amplification and then some shaping before
:the feeding into that decoder chip to confirm authentication of the xmitted series digital stream...that is why the dip switches are nearby and tied into that unit, confirm that the xmit unit is set up the same way (code)…thank goodness that you are not up against any of the newer units with an infinitely more complex rollover coding technique used.
:
:
:
:It is possible to loosely couple into the output of the receiver audio with an ~ .001 ufd capacitor and then feed into a signal tracer / audio amplifier and actually hear the incoming xmitted signal to confirm that the receiver is receiving the tonal digital burst of signal from the xmitter, (chirp) thus confirming that the xmitter is putting out, coded, and the receiver tuning and performance is good to that AF point.
: WITHOUT an incoming signal, one should hear the omnipresent white noise hiss of a superregen receiver…easy to utilize when you are initially probing for locating that point in the receiver where audio is, or it will also be found at a pin of the decoder chip.
:
:
:If you could provide a closeup pic of both sides of the board…...more help could be forthcoming. Also some code dates on parts would be helpful in the dating of that unit.
:
:
:
:
:
:73's de Edd
:
Edd, and all:
We seem to be misconnected here. Here is the way the library works:
There are four doors. All open outward. There is an interlock system with two doors to the outside air, and two more to get into the library. People generally use their right hand doors to enter or leave.
As you enter from the parking lot, there is, on the right, a 4x6" aluminum pillar about waist high. On the front of this pillar is a disk, about 6" in diameter. At the top of the pillar is a plastic cover. If you press this disk, the door opens for wheelchairs. The doors are identical. Inside the door is a GDO receiver, Paralleled to the wires that come from the push bar. It would appear that, to meet the Americans With Disabilities Act, someone just added a GDO receiver to the existing door. (Why the hell he couldn't do this with twenty feet of doorbell wire, I don't know). But, the circuit boards inside the columns are obviously removed from a GDO transmitter, even to having a LED that no one will ever see unless he takes the thing apart. It's also obvious that the push button switch was removed and two wires go down to a microswitch behind the round disk. Pushing the disk does the same thing as pushing a GDO attached to your sun visor. The transmitter (and the receiver) are programmed with the 10 position dip switch, and ten of the eighteen pins on the DIP chip are connected to the switch. This will give 1024 discrete codes, not at all like the rolling codes of today. I can take a good transmitter and open any door I switch the code into.
My problem, there is one door with the transmitter outside of the building completely. This board has been exposed to extremes of temperature, humidity, and vandalism. This board is corroded and cracked. I can place any other transmitter board in the outside column, and it works fine. So, I have the guilty board right next to me. I think I have found the problem, a corroded trace on the board, which I resoldered. (Oh, by the way, the board was intermittent). I rang this thing out all yesterday afternoon (I use a continuity checker that actually passes current through the board, and I think I found a corroded joint that I missed. Believe me, this board is going to be completely resoldered and coated with about three thousand coats of conformal before I take it back. I think the chip is good. We'll see.
Lewis
:
:
:
::
::
::
::
::
::
::Sir Lewis.....
::
::
::Ahhhhh Sooooo….seems like with more info coming forth…more info can be fed back to you.
::
::
::Sounds like that unit might be a late 80’s possibly on into the early ‘90’s vintage…and with that pin count out …on a DIP…
:: I feel that your “mystery chip” is the digital decoder chip of the receiver for the code stream that is sent via the RF of the xmitter.Look for a companion in the xmitter unit
::
::I feel sure that the RF aspect is probably the common 1 xstr superregenerative receiver, incorporated since day one of the transistorization of units . Look at the board closely where the antenna connection comes in and the closest discrete xstr nearby should be that unit. That is also confirmable by the very old generation technique of a hairpin loop of very heavy wire being used as its inductive element of its tuned LC network of the receiver. However, real soon afterwards the inductor was formed stripline as an etched inductor on the PCB foil path…totally plausible at the higher assigned RF frequencies incorporated by GDO’s..
::
::
::
::After detection of the signal back to an audio element there should be a stage of amplification and then some shaping before
::the feeding into that decoder chip to confirm authentication of the xmitted series digital stream...that is why the dip switches are nearby and tied into that unit, confirm that the xmit unit is set up the same way (code)…thank goodness that you are not up against any of the newer units with an infinitely more complex rollover coding technique used.
::
::
::
::It is possible to loosely couple into the output of the receiver audio with an ~ .001 ufd capacitor and then feed into a signal tracer / audio amplifier and actually hear the incoming xmitted signal to confirm that the receiver is receiving the tonal digital burst of signal from the xmitter, (chirp) thus confirming that the xmitter is putting out, coded, and the receiver tuning and performance is good to that AF point.
:: WITHOUT an incoming signal, one should hear the omnipresent white noise hiss of a superregen receiver…easy to utilize when you are initially probing for locating that point in the receiver where audio is, or it will also be found at a pin of the decoder chip.
::
::
::If you could provide a closeup pic of both sides of the board…...more help could be forthcoming. Also some code dates on parts would be helpful in the dating of that unit.
::
::
::
::
::
::73's de Edd
::
:
:
:Edd, and all:
:We seem to be misconnected here. Here is the way the library works:
:
:There are four doors. All open outward. There is an interlock system with two doors to the outside air, and two more to get into the library. People generally use their right hand doors to enter or leave.
:As you enter from the parking lot, there is, on the right, a 4x6" aluminum pillar about waist high. On the front of this pillar is a disk, about 6" in diameter. At the top of the pillar is a plastic cover. If you press this disk, the door opens for wheelchairs. The doors are identical. Inside the door is a GDO receiver, Paralleled to the wires that come from the push bar. It would appear that, to meet the Americans With Disabilities Act, someone just added a GDO receiver to the existing door. (Why the hell he couldn't do this with twenty feet of doorbell wire, I don't know). But, the circuit boards inside the columns are obviously removed from a GDO transmitter, even to having a LED that no one will ever see unless he takes the thing apart. It's also obvious that the push button switch was removed and two wires go down to a microswitch behind the round disk. Pushing the disk does the same thing as pushing a GDO attached to your sun visor. The transmitter (and the receiver) are programmed with the 10 position dip switch, and ten of the eighteen pins on the DIP chip are connected to the switch. This will give 1024 discrete codes, not at all like the rolling codes of today. I can take a good transmitter and open any door I switch the code into.
:
:My problem, there is one door with the transmitter outside of the building completely. This board has been exposed to extremes of temperature, humidity, and vandalism. This board is corroded and cracked. I can place any other transmitter board in the outside column, and it works fine. So, I have the guilty board right next to me. I think I have found the problem, a corroded trace on the board, which I resoldered. (Oh, by the way, the board was intermittent). I rang this thing out all yesterday afternoon (I use a continuity checker that actually passes current through the board, and I think I found a corroded joint that I missed. Believe me, this board is going to be completely resoldered and coated with about three thousand coats of conformal before I take it back. I think the chip is good. We'll see.
:Lewis
Sir Lewis.....
See…… we didn’t know ALL of the minutiae , until just now.
Now, with the minimum of at least two xmitters at a portal, could one possibly end up using another xmiter unit that received less use or was in a more sheltered area. That puts the best unit at that possibly more active area that you are now working on.
My collegiate site uses the same technique…but I know that those units are hard wired, since they are in metal columns !
My situation….. I probably would opt for using a 6 mil… or heavier…clear poly / vinyl bag and use a bag maker heating element to just make a custom fit around the unit and seal off the wiring entries with liquid vinyl , let all cure and then seal off the open end of the bag and cut a small corner tab and pressure confirm that all is sealed airtight and then pull a vacuum at that tab ..by mouth…. and pressure clamp off the tab and then vinyl seal that section corner. One hermetically sealed unit then being had, with no rain, humidity or condensation problems.
The reasoning, is that multiple coats of conformal, over ALL of the xmitter board should skew the freq enough to require a potential retuning of the ceramic trimmer tuning cap of the receiver.
Any who…from what you describe….sounds like all is about to come together….
73's de Edd
:::
:::
:::
:::
:::
:::
:::Sir Lewis.....
:::
:::
:::Ahhhhh Sooooo….seems like with more info coming forth…more info can be fed back to you.
:::
:::
:::Sounds like that unit might be a late 80’s possibly on into the early ‘90’s vintage…and with that pin count out …on a DIP…
::: I feel that your “mystery chip” is the digital decoder chip of the receiver for the code stream that is sent via the RF of the xmitter.Look for a companion in the xmitter unit
:::
:::I feel sure that the RF aspect is probably the common 1 xstr superregenerative receiver, incorporated since day one of the transistorization of units . Look at the board closely where the antenna connection comes in and the closest discrete xstr nearby should be that unit. That is also confirmable by the very old generation technique of a hairpin loop of very heavy wire being used as its inductive element of its tuned LC network of the receiver. However, real soon afterwards the inductor was formed stripline as an etched inductor on the PCB foil path…totally plausible at the higher assigned RF frequencies incorporated by GDO’s..
:::
:::
:::
:::After detection of the signal back to an audio element there should be a stage of amplification and then some shaping before
:::the feeding into that decoder chip to confirm authentication of the xmitted series digital stream...that is why the dip switches are nearby and tied into that unit, confirm that the xmit unit is set up the same way (code)…thank goodness that you are not up against any of the newer units with an infinitely more complex rollover coding technique used.
:::
:::
:::
:::It is possible to loosely couple into the output of the receiver audio with an ~ .001 ufd capacitor and then feed into a signal tracer / audio amplifier and actually hear the incoming xmitted signal to confirm that the receiver is receiving the tonal digital burst of signal from the xmitter, (chirp) thus confirming that the xmitter is putting out, coded, and the receiver tuning and performance is good to that AF point.
::: WITHOUT an incoming signal, one should hear the omnipresent white noise hiss of a superregen receiver…easy to utilize when you are initially probing for locating that point in the receiver where audio is, or it will also be found at a pin of the decoder chip.
:::
:::
:::If you could provide a closeup pic of both sides of the board…...more help could be forthcoming. Also some code dates on parts would be helpful in the dating of that unit.
:::
:::
:::
:::
:::
:::73's de Edd
:::
::
::
::Edd, and all:
::We seem to be misconnected here. Here is the way the library works:
::
::There are four doors. All open outward. There is an interlock system with two doors to the outside air, and two more to get into the library. People generally use their right hand doors to enter or leave.
::As you enter from the parking lot, there is, on the right, a 4x6" aluminum pillar about waist high. On the front of this pillar is a disk, about 6" in diameter. At the top of the pillar is a plastic cover. If you press this disk, the door opens for wheelchairs. The doors are identical. Inside the door is a GDO receiver, Paralleled to the wires that come from the push bar. It would appear that, to meet the Americans With Disabilities Act, someone just added a GDO receiver to the existing door. (Why the hell he couldn't do this with twenty feet of doorbell wire, I don't know). But, the circuit boards inside the columns are obviously removed from a GDO transmitter, even to having a LED that no one will ever see unless he takes the thing apart. It's also obvious that the push button switch was removed and two wires go down to a microswitch behind the round disk. Pushing the disk does the same thing as pushing a GDO attached to your sun visor. The transmitter (and the receiver) are programmed with the 10 position dip switch, and ten of the eighteen pins on the DIP chip are connected to the switch. This will give 1024 discrete codes, not at all like the rolling codes of today. I can take a good transmitter and open any door I switch the code into.
::
::My problem, there is one door with the transmitter outside of the building completely. This board has been exposed to extremes of temperature, humidity, and vandalism. This board is corroded and cracked. I can place any other transmitter board in the outside column, and it works fine. So, I have the guilty board right next to me. I think I have found the problem, a corroded trace on the board, which I resoldered. (Oh, by the way, the board was intermittent). I rang this thing out all yesterday afternoon (I use a continuity checker that actually passes current through the board, and I think I found a corroded joint that I missed. Believe me, this board is going to be completely resoldered and coated with about three thousand coats of conformal before I take it back. I think the chip is good. We'll see.
::Lewis
:
:
:
:
:
:
: Sir Lewis.....
:
:
:See…… we didn’t know ALL of the minutiae , until just now.
:
:
:Now, with the minimum of at least two xmitters at a portal, could one possibly end up using another xmiter unit that received less use or was in a more sheltered area. That puts the best unit at that possibly more active area that you are now working on.
:
:
:My collegiate site uses the same technique…but I know that those units are hard wired, since they are in metal columns !
:
:My situation….. I probably would opt for using a 6 mil… or heavier…clear poly / vinyl bag and use a bag maker heating element to just make a custom fit around the unit and seal off the wiring entries with liquid vinyl , let all cure and then seal off the open end of the bag and cut a small corner tab and pressure confirm that all is sealed airtight and then pull a vacuum at that tab ..by mouth…. and pressure clamp off the tab and then vinyl seal that section corner. One hermetically sealed unit then being had, with no rain, humidity or condensation problems.
:
:
:The reasoning, is that multiple coats of conformal, over ALL of the xmitter board should skew the freq enough to require a potential retuning of the ceramic trimmer tuning cap of the receiver.
:
:
:Any who…from what you describe….sounds like all is about to come together….
:
:
:
:73's de Edd
:
I got the impression from the internet that these things work around 300mHz, I have nothing to scan that as it is military aircraft or something, so I put my scanner antenna next to the transistor and started scanning around 145-155, and got a hit at 145.someting, so I put a push button in the microswitch terminals, and I definately get computer noise when I press the button. I hope that I have jumpered over all the corrosion, and when I get thru, H2O will never touch this board again.
Your CT7001 chip sez it is 3:22:50.
Lewis
::::
::::
::::
::::
::::
::::
::::Sir Lewis.....
::::
::::
::::Ahhhhh Sooooo….seems like with more info coming forth…more info can be fed back to you.
::::
::::
::::Sounds like that unit might be a late 80’s possibly on into the early ‘90’s vintage…and with that pin count out …on a DIP…
:::: I feel that your “mystery chip” is the digital decoder chip of the receiver for the code stream that is sent via the RF of the xmitter.Look for a companion in the xmitter unit
::::
::::I feel sure that the RF aspect is probably the common 1 xstr superregenerative receiver, incorporated since day one of the transistorization of units . Look at the board closely where the antenna connection comes in and the closest discrete xstr nearby should be that unit. That is also confirmable by the very old generation technique of a hairpin loop of very heavy wire being used as its inductive element of its tuned LC network of the receiver. However, real soon afterwards the inductor was formed stripline as an etched inductor on the PCB foil path…totally plausible at the higher assigned RF frequencies incorporated by GDO’s..
::::
::::
::::
::::After detection of the signal back to an audio element there should be a stage of amplification and then some shaping before
::::the feeding into that decoder chip to confirm authentication of the xmitted series digital stream...that is why the dip switches are nearby and tied into that unit, confirm that the xmit unit is set up the same way (code)…thank goodness that you are not up against any of the newer units with an infinitely more complex rollover coding technique used.
::::
::::
::::
::::It is possible to loosely couple into the output of the receiver audio with an ~ .001 ufd capacitor and then feed into a signal tracer / audio amplifier and actually hear the incoming xmitted signal to confirm that the receiver is receiving the tonal digital burst of signal from the xmitter, (chirp) thus confirming that the xmitter is putting out, coded, and the receiver tuning and performance is good to that AF point.
:::: WITHOUT an incoming signal, one should hear the omnipresent white noise hiss of a superregen receiver…easy to utilize when you are initially probing for locating that point in the receiver where audio is, or it will also be found at a pin of the decoder chip.
::::
::::
::::If you could provide a closeup pic of both sides of the board…...more help could be forthcoming. Also some code dates on parts would be helpful in the dating of that unit.
::::
::::
::::
::::
::::
::::73's de Edd
::::
:::
:::
:::Edd, and all:
:::We seem to be misconnected here. Here is the way the library works:
:::
:::There are four doors. All open outward. There is an interlock system with two doors to the outside air, and two more to get into the library. People generally use their right hand doors to enter or leave.
:::As you enter from the parking lot, there is, on the right, a 4x6" aluminum pillar about waist high. On the front of this pillar is a disk, about 6" in diameter. At the top of the pillar is a plastic cover. If you press this disk, the door opens for wheelchairs. The doors are identical. Inside the door is a GDO receiver, Paralleled to the wires that come from the push bar. It would appear that, to meet the Americans With Disabilities Act, someone just added a GDO receiver to the existing door. (Why the hell he couldn't do this with twenty feet of doorbell wire, I don't know). But, the circuit boards inside the columns are obviously removed from a GDO transmitter, even to having a LED that no one will ever see unless he takes the thing apart. It's also obvious that the push button switch was removed and two wires go down to a microswitch behind the round disk. Pushing the disk does the same thing as pushing a GDO attached to your sun visor. The transmitter (and the receiver) are programmed with the 10 position dip switch, and ten of the eighteen pins on the DIP chip are connected to the switch. This will give 1024 discrete codes, not at all like the rolling codes of today. I can take a good transmitter and open any door I switch the code into.
:::
:::My problem, there is one door with the transmitter outside of the building completely. This board has been exposed to extremes of temperature, humidity, and vandalism. This board is corroded and cracked. I can place any other transmitter board in the outside column, and it works fine. So, I have the guilty board right next to me. I think I have found the problem, a corroded trace on the board, which I resoldered. (Oh, by the way, the board was intermittent). I rang this thing out all yesterday afternoon (I use a continuity checker that actually passes current through the board, and I think I found a corroded joint that I missed. Believe me, this board is going to be completely resoldered and coated with about three thousand coats of conformal before I take it back. I think the chip is good. We'll see.
:::Lewis
::
::
::
::
::
::
:: Sir Lewis.....
::
::
::See…… we didn’t know ALL of the minutiae , until just now.
::
::
::Now, with the minimum of at least two xmitters at a portal, could one possibly end up using another xmiter unit that received less use or was in a more sheltered area. That puts the best unit at that possibly more active area that you are now working on.
::
::
::My collegiate site uses the same technique…but I know that those units are hard wired, since they are in metal columns !
::
::My situation….. I probably would opt for using a 6 mil… or heavier…clear poly / vinyl bag and use a bag maker heating element to just make a custom fit around the unit and seal off the wiring entries with liquid vinyl , let all cure and then seal off the open end of the bag and cut a small corner tab and pressure confirm that all is sealed airtight and then pull a vacuum at that tab ..by mouth…. and pressure clamp off the tab and then vinyl seal that section corner. One hermetically sealed unit then being had, with no rain, humidity or condensation problems.
::
::
::The reasoning, is that multiple coats of conformal, over ALL of the xmitter board should skew the freq enough to require a potential retuning of the ceramic trimmer tuning cap of the receiver.
::
::
::Any who…from what you describe….sounds like all is about to come together….
::
::
::
::73's de Edd
::
:
:I got the impression from the internet that these things work around 300mHz, I have nothing to scan that as it is military aircraft or something, so I put my scanner antenna next to the transistor and started scanning around 145-155, and got a hit at 145.someting, so I put a push button in the microswitch terminals, and I definately get computer noise when I press the button. I hope that I have jumpered over all the corrosion, and when I get thru, H2O will never touch this board again.
:Your CT7001 chip sez it is 3:22:50.
:Lewis
All:
Off to library to see if it is fixed. Will let you know.
Lewis
:::::
:::::
:::::
:::::
:::::
:::::
:::::Sir Lewis.....
:::::
:::::
:::::Ahhhhh Sooooo….seems like with more info coming forth…more info can be fed back to you.
:::::
:::::
:::::Sounds like that unit might be a late 80’s possibly on into the early ‘90’s vintage…and with that pin count out …on a DIP…
::::: I feel that your “mystery chip” is the digital decoder chip of the receiver for the code stream that is sent via the RF of the xmitter.Look for a companion in the xmitter unit
:::::
:::::I feel sure that the RF aspect is probably the common 1 xstr superregenerative receiver, incorporated since day one of the transistorization of units . Look at the board closely where the antenna connection comes in and the closest discrete xstr nearby should be that unit. That is also confirmable by the very old generation technique of a hairpin loop of very heavy wire being used as its inductive element of its tuned LC network of the receiver. However, real soon afterwards the inductor was formed stripline as an etched inductor on the PCB foil path…totally plausible at the higher assigned RF frequencies incorporated by GDO’s..
:::::
:::::
:::::
:::::After detection of the signal back to an audio element there should be a stage of amplification and then some shaping before
:::::the feeding into that decoder chip to confirm authentication of the xmitted series digital stream...that is why the dip switches are nearby and tied into that unit, confirm that the xmit unit is set up the same way (code)…thank goodness that you are not up against any of the newer units with an infinitely more complex rollover coding technique used.
:::::
:::::
:::::
:::::It is possible to loosely couple into the output of the receiver audio with an ~ .001 ufd capacitor and then feed into a signal tracer / audio amplifier and actually hear the incoming xmitted signal to confirm that the receiver is receiving the tonal digital burst of signal from the xmitter, (chirp) thus confirming that the xmitter is putting out, coded, and the receiver tuning and performance is good to that AF point.
::::: WITHOUT an incoming signal, one should hear the omnipresent white noise hiss of a superregen receiver…easy to utilize when you are initially probing for locating that point in the receiver where audio is, or it will also be found at a pin of the decoder chip.
:::::
:::::
:::::If you could provide a closeup pic of both sides of the board…...more help could be forthcoming. Also some code dates on parts would be helpful in the dating of that unit.
:::::
:::::
:::::
:::::
:::::
:::::73's de Edd
:::::
::::
::::
::::Edd, and all:
::::We seem to be misconnected here. Here is the way the library works:
::::
::::There are four doors. All open outward. There is an interlock system with two doors to the outside air, and two more to get into the library. People generally use their right hand doors to enter or leave.
::::As you enter from the parking lot, there is, on the right, a 4x6" aluminum pillar about waist high. On the front of this pillar is a disk, about 6" in diameter. At the top of the pillar is a plastic cover. If you press this disk, the door opens for wheelchairs. The doors are identical. Inside the door is a GDO receiver, Paralleled to the wires that come from the push bar. It would appear that, to meet the Americans With Disabilities Act, someone just added a GDO receiver to the existing door. (Why the hell he couldn't do this with twenty feet of doorbell wire, I don't know). But, the circuit boards inside the columns are obviously removed from a GDO transmitter, even to having a LED that no one will ever see unless he takes the thing apart. It's also obvious that the push button switch was removed and two wires go down to a microswitch behind the round disk. Pushing the disk does the same thing as pushing a GDO attached to your sun visor. The transmitter (and the receiver) are programmed with the 10 position dip switch, and ten of the eighteen pins on the DIP chip are connected to the switch. This will give 1024 discrete codes, not at all like the rolling codes of today. I can take a good transmitter and open any door I switch the code into.
::::
::::My problem, there is one door with the transmitter outside of the building completely. This board has been exposed to extremes of temperature, humidity, and vandalism. This board is corroded and cracked. I can place any other transmitter board in the outside column, and it works fine. So, I have the guilty board right next to me. I think I have found the problem, a corroded trace on the board, which I resoldered. (Oh, by the way, the board was intermittent). I rang this thing out all yesterday afternoon (I use a continuity checker that actually passes current through the board, and I think I found a corroded joint that I missed. Believe me, this board is going to be completely resoldered and coated with about three thousand coats of conformal before I take it back. I think the chip is good. We'll see.
::::Lewis
:::
:::
:::
:::
:::
:::
::: Sir Lewis.....
:::
:::
:::See…… we didn’t know ALL of the minutiae , until just now.
:::
:::
:::Now, with the minimum of at least two xmitters at a portal, could one possibly end up using another xmiter unit that received less use or was in a more sheltered area. That puts the best unit at that possibly more active area that you are now working on.
:::
:::
:::My collegiate site uses the same technique…but I know that those units are hard wired, since they are in metal columns !
:::
:::My situation….. I probably would opt for using a 6 mil… or heavier…clear poly / vinyl bag and use a bag maker heating element to just make a custom fit around the unit and seal off the wiring entries with liquid vinyl , let all cure and then seal off the open end of the bag and cut a small corner tab and pressure confirm that all is sealed airtight and then pull a vacuum at that tab ..by mouth…. and pressure clamp off the tab and then vinyl seal that section corner. One hermetically sealed unit then being had, with no rain, humidity or condensation problems.
:::
:::
:::The reasoning, is that multiple coats of conformal, over ALL of the xmitter board should skew the freq enough to require a potential retuning of the ceramic trimmer tuning cap of the receiver.
:::
:::
:::Any who…from what you describe….sounds like all is about to come together….
:::
:::
:::
:::73's de Edd
:::
::
::I got the impression from the internet that these things work around 300mHz, I have nothing to scan that as it is military aircraft or something, so I put my scanner antenna next to the transistor and started scanning around 145-155, and got a hit at 145.someting, so I put a push button in the microswitch terminals, and I definately get computer noise when I press the button. I hope that I have jumpered over all the corrosion, and when I get thru, H2O will never touch this board again.
::Your CT7001 chip sez it is 3:22:50.
::Lewis
:
:All:
:Off to library to see if it is fixed. Will let you know.
:
:Lewis
Yaaaaaa=Hooooooooo good peoples.....the whole problem was corroded board. Went to the library, I can open doors (all of them by changing DIP switch) from the parking lot. The board is going to get totally reflowed (it has that green crap over the traces) and sealed with forty coats of acrylic, and installed in the post and will work good and last a long time.
Thanx all,
Lewis
Reminds me of an intermittent broken trace on a pc board for a Delco AM/FM car radio I fixed a couple weeks ago. The trace was really small, and ran to a much larger pad where a surface mount cap was soldered. It was the reset line on a microcontroller tied to a 5V source. Needless to say, when it made contact, the microcontroller worked fine, but when it lost contact, the whole radio locked up. Used a new std cap with leads to bridge the gap, and it works fine now.
marv
::::::
::::::
::::::
::::::
::::::
::::::
::::::
::::::Sir Lewis.....
::::::
::::::
::::::Ahhhhh Sooooo….seems like with more info coming forth…more info can be fed back to you.
::::::
::::::
::::::Sounds like that unit might be a late 80’s possibly on into the early ‘90’s vintage…and with that pin count out …on a DIP…
:::::: I feel that your “mystery chip” is the digital decoder chip of the receiver for the code stream that is sent via the RF of the xmitter.Look for a companion in the xmitter unit
::::::
::::::I feel sure that the RF aspect is probably the common 1 xstr superregenerative receiver, incorporated since day one of the transistorization of units . Look at the board closely where the antenna connection comes in and the closest discrete xstr nearby should be that unit. That is also confirmable by the very old generation technique of a hairpin loop of very heavy wire being used as its inductive element of its tuned LC network of the receiver. However, real soon afterwards the inductor was formed stripline as an etched inductor on the PCB foil path…totally plausible at the higher assigned RF frequencies incorporated by GDO’s..
::::::
::::::
::::::
::::::After detection of the signal back to an audio element there should be a stage of amplification and then some shaping before
::::::the feeding into that decoder chip to confirm authentication of the xmitted series digital stream...that is why the dip switches are nearby and tied into that unit, confirm that the xmit unit is set up the same way (code)…thank goodness that you are not up against any of the newer units with an infinitely more complex rollover coding technique used.
::::::
::::::
::::::
::::::It is possible to loosely couple into the output of the receiver audio with an ~ .001 ufd capacitor and then feed into a signal tracer / audio amplifier and actually hear the incoming xmitted signal to confirm that the receiver is receiving the tonal digital burst of signal from the xmitter, (chirp) thus confirming that the xmitter is putting out, coded, and the receiver tuning and performance is good to that AF point.
:::::: WITHOUT an incoming signal, one should hear the omnipresent white noise hiss of a superregen receiver…easy to utilize when you are initially probing for locating that point in the receiver where audio is, or it will also be found at a pin of the decoder chip.
::::::
::::::
::::::If you could provide a closeup pic of both sides of the board…...more help could be forthcoming. Also some code dates on parts would be helpful in the dating of that unit.
::::::
::::::
::::::
::::::
::::::
::::::73's de Edd
::::::
:::::
:::::
:::::Edd, and all:
:::::We seem to be misconnected here. Here is the way the library works:
:::::
:::::There are four doors. All open outward. There is an interlock system with two doors to the outside air, and two more to get into the library. People generally use their right hand doors to enter or leave.
:::::As you enter from the parking lot, there is, on the right, a 4x6" aluminum pillar about waist high. On the front of this pillar is a disk, about 6" in diameter. At the top of the pillar is a plastic cover. If you press this disk, the door opens for wheelchairs. The doors are identical. Inside the door is a GDO receiver, Paralleled to the wires that come from the push bar. It would appear that, to meet the Americans With Disabilities Act, someone just added a GDO receiver to the existing door. (Why the hell he couldn't do this with twenty feet of doorbell wire, I don't know). But, the circuit boards inside the columns are obviously removed from a GDO transmitter, even to having a LED that no one will ever see unless he takes the thing apart. It's also obvious that the push button switch was removed and two wires go down to a microswitch behind the round disk. Pushing the disk does the same thing as pushing a GDO attached to your sun visor. The transmitter (and the receiver) are programmed with the 10 position dip switch, and ten of the eighteen pins on the DIP chip are connected to the switch. This will give 1024 discrete codes, not at all like the rolling codes of today. I can take a good transmitter and open any door I switch the code into.
:::::
:::::My problem, there is one door with the transmitter outside of the building completely. This board has been exposed to extremes of temperature, humidity, and vandalism. This board is corroded and cracked. I can place any other transmitter board in the outside column, and it works fine. So, I have the guilty board right next to me. I think I have found the problem, a corroded trace on the board, which I resoldered. (Oh, by the way, the board was intermittent). I rang this thing out all yesterday afternoon (I use a continuity checker that actually passes current through the board, and I think I found a corroded joint that I missed. Believe me, this board is going to be completely resoldered and coated with about three thousand coats of conformal before I take it back. I think the chip is good. We'll see.
:::::Lewis
::::
::::
::::
::::
::::
::::
:::: Sir Lewis.....
::::
::::
::::See…… we didn’t know ALL of the minutiae , until just now.
::::
::::
::::Now, with the minimum of at least two xmitters at a portal, could one possibly end up using another xmiter unit that received less use or was in a more sheltered area. That puts the best unit at that possibly more active area that you are now working on.
::::
::::
::::My collegiate site uses the same technique…but I know that those units are hard wired, since they are in metal columns !
::::
::::My situation….. I probably would opt for using a 6 mil… or heavier…clear poly / vinyl bag and use a bag maker heating element to just make a custom fit around the unit and seal off the wiring entries with liquid vinyl , let all cure and then seal off the open end of the bag and cut a small corner tab and pressure confirm that all is sealed airtight and then pull a vacuum at that tab ..by mouth…. and pressure clamp off the tab and then vinyl seal that section corner. One hermetically sealed unit then being had, with no rain, humidity or condensation problems.
::::
::::
::::The reasoning, is that multiple coats of conformal, over ALL of the xmitter board should skew the freq enough to require a potential retuning of the ceramic trimmer tuning cap of the receiver.
::::
::::
::::Any who…from what you describe….sounds like all is about to come together….
::::
::::
::::
::::73's de Edd
::::
:::
:::I got the impression from the internet that these things work around 300mHz, I have nothing to scan that as it is military aircraft or something, so I put my scanner antenna next to the transistor and started scanning around 145-155, and got a hit at 145.someting, so I put a push button in the microswitch terminals, and I definately get computer noise when I press the button. I hope that I have jumpered over all the corrosion, and when I get thru, H2O will never touch this board again.
:::Your CT7001 chip sez it is 3:22:50.
:::Lewis
::
::All:
::Off to library to see if it is fixed. Will let you know.
::
::Lewis
:
:Yaaaaaa=Hooooooooo good peoples.....the whole problem was corroded board. Went to the library, I can open doors (all of them by changing DIP switch) from the parking lot. The board is going to get totally reflowed (it has that green crap over the traces) and sealed with forty coats of acrylic, and installed in the post and will work good and last a long time.
:Thanx all,
:Lewis
:Reminds me of an intermittent broken trace on a pc board for a Delco AM/FM car radio I fixed a couple weeks ago. The trace was really small, and ran to a much larger pad where a surface mount cap was soldered. It was the reset line on a microcontroller tied to a 5V source. Needless to say, when it made contact, the microcontroller worked fine, but when it lost contact, the whole radio locked up. Used a new std cap with leads to bridge the gap, and it works fine now.
:
:marv
<*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*>
Happy ending to story:
When thesee were first installed, the transmitters for the door openers didn't work properly, people opening garage doors tend to hold the button down until the door opens, while in this useage, they tend to slap the disk as they walk or roll by, which doesn't give the door a long enough start pulse. To remedy this, they put a 1,000 uF cap across the switch contacts, always charged. When the switch is pushed, the cap discharges and keeps the start pulse on for about one second. The person that did the mod did not reseal the board. With nine Volts on the board all the time, moisture got under the green stuff and started electrolyzing the copper. As the years passed the trace eventually became a resistor. Scratching the trace (which looked fine) with a scribe produced a very corroded trace. A careful reflowing and replacement with bus bar got the thing working like new! It is going to be a long time before it corrodes again.
Thanz for yer help,
Lewis
<*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*>
::Lewis,
::Reminds me of an intermittent broken trace on a pc board for a Delco AM/FM car radio I fixed a couple weeks ago. The trace was really small, and ran to a much larger pad where a surface mount cap was soldered. It was the reset line on a microcontroller tied to a 5V source. Needless to say, when it made contact, the microcontroller worked fine, but when it lost contact, the whole radio locked up. Used a new std cap with leads to bridge the gap, and it works fine now.
::
::marv
:
:
:
:<*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*>
:
:Happy ending to story:
:When thesee were first installed, the transmitters for the door openers didn't work properly, people opening garage doors tend to hold the button down until the door opens, while in this useage, they tend to slap the disk as they walk or roll by, which doesn't give the door a long enough start pulse. To remedy this, they put a 1,000 uF cap across the switch contacts, always charged. When the switch is pushed, the cap discharges and keeps the start pulse on for about one second. The person that did the mod did not reseal the board. With nine Volts on the board all the time, moisture got under the green stuff and started electrolyzing the copper. As the years passed the trace eventually became a resistor. Scratching the trace (which looked fine) with a scribe produced a very corroded trace. A careful reflowing and replacement with bus bar got the thing working like new! It is going to be a long time before it corrodes again.
:Thanz for yer help,
:Lewis
:<*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*>
:
: Along these lines, remote controlers, does anyone know of a source for a universal garage door remote control system? I have a 2 Radio Shack units Cat # 61-2107 which are now over 25 years old and I am thinking their life expectancy is running out. They operate off the the low voltage across the open switch terminals, I don't even need a transformer to power them. Radio Shack has discontinued them. Any help would be appreciated. PL
:
:::Lewis,
:::Reminds me of an intermittent broken trace on a pc board for a Delco AM/FM car radio I fixed a couple weeks ago. The trace was really small, and ran to a much larger pad where a surface mount cap was soldered. It was the reset line on a microcontroller tied to a 5V source. Needless to say, when it made contact, the microcontroller worked fine, but when it lost contact, the whole radio locked up. Used a new std cap with leads to bridge the gap, and it works fine now.
:::
:::marv
::
::
::
::<*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*>
::
::Happy ending to story:
::When thesee were first installed, the transmitters for the door openers didn't work properly, people opening garage doors tend to hold the button down until the door opens, while in this useage, they tend to slap the disk as they walk or roll by, which doesn't give the door a long enough start pulse. To remedy this, they put a 1,000 uF cap across the switch contacts, always charged. When the switch is pushed, the cap discharges and keeps the start pulse on for about one second. The person that did the mod did not reseal the board. With nine Volts on the board all the time, moisture got under the green stuff and started electrolyzing the copper. As the years passed the trace eventually became a resistor. Scratching the trace (which looked fine) with a scribe produced a very corroded trace. A careful reflowing and replacement with bus bar got the thing working like new! It is going to be a long time before it corrodes again.
::Thanz for yer help,
::Lewis
::<*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*><*>
::
:http://www.ajprindle.com/products/sku-12940__src-tl.html
:
:: Along these lines, remote controlers, does anyone know of a source for a universal garage door remote control system? I have a 2 Radio Shack units Cat # 61-2107 which are now over 25 years old and I am thinking their life expectancy is running out. They operate off the the low voltage across the open switch terminals, I don't even need a transformer to power them. Radio Shack has discontinued them. Any help would be appreciated. PL
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::::Lewis,
::::Reminds me of an intermittent broken trace on a pc board for a Delco AM/FM car radio I fixed a couple weeks ago. The trace was really small, and ran to a much larger pad where a surface mount cap was soldered. It was the reset line on a microcontroller tied to a 5V source. Needless to say, when it made contact, the microcontroller worked fine, but when it lost contact, the whole radio locked up. Used a new std cap with leads to bridge the gap, and it works fine now.
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::::marv
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:::Happy ending to story:
:::When thesee were first installed, the transmitters for the door openers didn't work properly, people opening garage doors tend to hold the button down until the door opens, while in this useage, they tend to slap the disk as they walk or roll by, which doesn't give the door a long enough start pulse. To remedy this, they put a 1,000 uF cap across the switch contacts, always charged. When the switch is pushed, the cap discharges and keeps the start pulse on for about one second. The person that did the mod did not reseal the board. With nine Volts on the board all the time, moisture got under the green stuff and started electrolyzing the copper. As the years passed the trace eventually became a resistor. Scratching the trace (which looked fine) with a scribe produced a very corroded trace. A careful reflowing and replacement with bus bar got the thing working like new! It is going to be a long time before it corrodes again.
:::Thanz for yer help,
:::Lewis
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