This is the continuing saga of a Tektronix 545 scope. Soon to be working perfectly after I solve this one last problem, or so I think it's the last problem.
Thanks,
Dave
Thanks,
Dave
:Hello All,
: Now that I got the HV tubes right and I did see them light up, But then the type CA module crapped out again, causing a resistor inside the scope to burn again and smoke and destroy itself this time. I have replaced it (NOS so nobody would ever know that it was ever replaced) and all is probably well inside the scope but I wont turn it on again until I solve this problem. Pin 8 on the module measures 2.5 ohms to the chassis. At first I thought it was the .005 mf capacitor but that's fine. I'm not sure if the 2.5 ohms is correct or not. I will now refer to the Type CA service data.
:
:This is the continuing saga of a Tektronix 545 scope. Soon to be working perfectly after I solve this one last problem, or so I think it's the last problem.
:
:Thanks,
:
:Dave
:
It has to be something. If anyone has any ideas, please help. If I find the culprit, I'll let everyone know what it is.
Thanks,
Dave
:Hello Again,
: Pin 8 is not where the problem is. It's probably pin 10 or with the plug-in module connector. Try as I might to find the problem, it doesn't exist. However when the module is plugged in there's a heavy load on the 100 v line. When the plug-in unit is plugged out, there is no such load.
: I can find no such load in the plug-in. I measure 6K ohms on pin 10. The only place there is a low resistance is on pins 2 and 8. I can see no problems with the plug or jack part of the connector. What's going on here? This makes not sense and it's extremely frustrating.
:
:Thanks,
:
:Dave
::Hello All,
:: Now that I got the HV tubes right and I did see them light up, But then the type CA module crapped out again, causing a resistor inside the scope to burn again and smoke and destroy itself this time. I have replaced it (NOS so nobody would ever know that it was ever replaced) and all is probably well inside the scope but I wont turn it on again until I solve this problem. Pin 8 on the module measures 2.5 ohms to the chassis. At first I thought it was the .005 mf capacitor but that's fine. I'm not sure if the 2.5 ohms is correct or not. I will now refer to the Type CA service data.
::
::This is the continuing saga of a Tektronix 545 scope. Soon to be working perfectly after I solve this one last problem, or so I think it's the last problem.
::
::Thanks,
::
::Dave
::
:
:Hello Again,
: There must be something inside the scope that is connecting when the module is plugged into the scope. But what? I don't think that the scope is possesed or anything. I don't see anythign awry with the connectors.
:
:It has to be something. If anyone has any ideas, please help. If I find the culprit, I'll let everyone know what it is.
:
:Thanks,
:
:Dave
::Hello Again,
:: Pin 8 is not where the problem is. It's probably pin 10 or with the plug-in module connector. Try as I might to find the problem, it doesn't exist. However when the module is plugged in there's a heavy load on the 100 v line. When the plug-in unit is plugged out, there is no such load.
:: I can find no such load in the plug-in. I measure 6K ohms on pin 10. The only place there is a low resistance is on pins 2 and 8. I can see no problems with the plug or jack part of the connector. What's going on here? This makes not sense and it's extremely frustrating.
::
::Thanks,
::
::Dave
:::Hello All,
::: Now that I got the HV tubes right and I did see them light up, But then the type CA module crapped out again, causing a resistor inside the scope to burn again and smoke and destroy itself this time. I have replaced it (NOS so nobody would ever know that it was ever replaced) and all is probably well inside the scope but I wont turn it on again until I solve this problem. Pin 8 on the module measures 2.5 ohms to the chassis. At first I thought it was the .005 mf capacitor but that's fine. I'm not sure if the 2.5 ohms is correct or not. I will now refer to the Type CA service data.
:::
:::This is the continuing saga of a Tektronix 545 scope. Soon to be working perfectly after I solve this one last problem, or so I think it's the last problem.
:::
:::Thanks,
:::
:::Dave
:::
::
:
Thanks,
Dave
:Just trace the 100 volt line through on the CA. If it's a heavy load, it will be a capacitor or tube. I'm not familiar with the CA; does it use transistors? The BAMA site has it in DJVU, which I can't open. Just put an ohmmeter on the line and start pulling tubes.
:Johnnysan-
:
:
::Hello Again,
:: There must be something inside the scope that is connecting when the module is plugged into the scope. But what? I don't think that the scope is possesed or anything. I don't see anythign awry with the connectors.
::
::It has to be something. If anyone has any ideas, please help. If I find the culprit, I'll let everyone know what it is.
::
::Thanks,
::
::Dave
:::Hello Again,
::: Pin 8 is not where the problem is. It's probably pin 10 or with the plug-in module connector. Try as I might to find the problem, it doesn't exist. However when the module is plugged in there's a heavy load on the 100 v line. When the plug-in unit is plugged out, there is no such load.
::: I can find no such load in the plug-in. I measure 6K ohms on pin 10. The only place there is a low resistance is on pins 2 and 8. I can see no problems with the plug or jack part of the connector. What's going on here? This makes not sense and it's extremely frustrating.
:::
:::Thanks,
:::
:::Dave
::::Hello All,
:::: Now that I got the HV tubes right and I did see them light up, But then the type CA module crapped out again, causing a resistor inside the scope to burn again and smoke and destroy itself this time. I have replaced it (NOS so nobody would ever know that it was ever replaced) and all is probably well inside the scope but I wont turn it on again until I solve this problem. Pin 8 on the module measures 2.5 ohms to the chassis. At first I thought it was the .005 mf capacitor but that's fine. I'm not sure if the 2.5 ohms is correct or not. I will now refer to the Type CA service data.
::::
::::This is the continuing saga of a Tektronix 545 scope. Soon to be working perfectly after I solve this one last problem, or so I think it's the last problem.
::::
::::Thanks,
::::
::::Dave
::::
:::
::
:
marv
:Johnnysan,
: I just traced the 100 volt line and there are no loads when the plug-in is disconnected from the scope. There is none in the scope to be found and none in the plug in. Once they are connected there is 124 ohms on the 100 volt line. When they are detached there is 500 K ohms on the 100 volt line in the scope and 2 K ohms in the module. Why does it go way down when they are mated? Where does this load go when the module is unplugged from the scope?
:That has been my question all along. How can I find a load that's not there? What's going on here? This is very strange and extremely frustrating.
:
:Thanks,
:
:Dave
:
::Just trace the 100 volt line through on the CA. If it's a heavy load, it will be a capacitor or tube. I'm not familiar with the CA; does it use transistors? The BAMA site has it in DJVU, which I can't open. Just put an ohmmeter on the line and start pulling tubes.
::Johnnysan-
::
::
:::Hello Again,
::: There must be something inside the scope that is connecting when the module is plugged into the scope. But what? I don't think that the scope is possesed or anything. I don't see anythign awry with the connectors.
:::
:::It has to be something. If anyone has any ideas, please help. If I find the culprit, I'll let everyone know what it is.
:::
:::Thanks,
:::
:::Dave
::::Hello Again,
:::: Pin 8 is not where the problem is. It's probably pin 10 or with the plug-in module connector. Try as I might to find the problem, it doesn't exist. However when the module is plugged in there's a heavy load on the 100 v line. When the plug-in unit is plugged out, there is no such load.
:::: I can find no such load in the plug-in. I measure 6K ohms on pin 10. The only place there is a low resistance is on pins 2 and 8. I can see no problems with the plug or jack part of the connector. What's going on here? This makes not sense and it's extremely frustrating.
::::
::::Thanks,
::::
::::Dave
:::::Hello All,
::::: Now that I got the HV tubes right and I did see them light up, But then the type CA module crapped out again, causing a resistor inside the scope to burn again and smoke and destroy itself this time. I have replaced it (NOS so nobody would ever know that it was ever replaced) and all is probably well inside the scope but I wont turn it on again until I solve this problem. Pin 8 on the module measures 2.5 ohms to the chassis. At first I thought it was the .005 mf capacitor but that's fine. I'm not sure if the 2.5 ohms is correct or not. I will now refer to the Type CA service data.
:::::
:::::This is the continuing saga of a Tektronix 545 scope. Soon to be working perfectly after I solve this one last problem, or so I think it's the last problem.
:::::
:::::Thanks,
:::::
:::::Dave
:::::
::::
:::
::
:
Thanks,
Dave
:Dave,
:If I remember correctly from my last use of a Tek 545 (60's), those plug-in and mating connectors were blue, (AMP comes to mind) and when being mated caused a wiping action and some displacement of the contacts. One or both also float to ease alignment when mating. If the main body or even the plug-in frame is slightly torqued, the float mechanism may cause a short to frame. Closely inspect both connector bodies for cracks that would allow distortion and possible pin movement at mating. Is it possible that a small hair of wire/solder blob is buried inside the connector body, and when mated/displaced pin is shorting to another pin?
:
:marv
:
::Johnnysan,
:: I just traced the 100 volt line and there are no loads when the plug-in is disconnected from the scope. There is none in the scope to be found and none in the plug in. Once they are connected there is 124 ohms on the 100 volt line. When they are detached there is 500 K ohms on the 100 volt line in the scope and 2 K ohms in the module. Why does it go way down when they are mated? Where does this load go when the module is unplugged from the scope?
::That has been my question all along. How can I find a load that's not there? What's going on here? This is very strange and extremely frustrating.
::
::Thanks,
::
::Dave
::
:::Just trace the 100 volt line through on the CA. If it's a heavy load, it will be a capacitor or tube. I'm not familiar with the CA; does it use transistors? The BAMA site has it in DJVU, which I can't open. Just put an ohmmeter on the line and start pulling tubes.
:::Johnnysan-
:::
:::
::::Hello Again,
:::: There must be something inside the scope that is connecting when the module is plugged into the scope. But what? I don't think that the scope is possesed or anything. I don't see anythign awry with the connectors.
::::
::::It has to be something. If anyone has any ideas, please help. If I find the culprit, I'll let everyone know what it is.
::::
::::Thanks,
::::
::::Dave
:::::Hello Again,
::::: Pin 8 is not where the problem is. It's probably pin 10 or with the plug-in module connector. Try as I might to find the problem, it doesn't exist. However when the module is plugged in there's a heavy load on the 100 v line. When the plug-in unit is plugged out, there is no such load.
::::: I can find no such load in the plug-in. I measure 6K ohms on pin 10. The only place there is a low resistance is on pins 2 and 8. I can see no problems with the plug or jack part of the connector. What's going on here? This makes not sense and it's extremely frustrating.
:::::
:::::Thanks,
:::::
:::::Dave
::::::Hello All,
:::::: Now that I got the HV tubes right and I did see them light up, But then the type CA module crapped out again, causing a resistor inside the scope to burn again and smoke and destroy itself this time. I have replaced it (NOS so nobody would ever know that it was ever replaced) and all is probably well inside the scope but I wont turn it on again until I solve this problem. Pin 8 on the module measures 2.5 ohms to the chassis. At first I thought it was the .005 mf capacitor but that's fine. I'm not sure if the 2.5 ohms is correct or not. I will now refer to the Type CA service data.
::::::
::::::This is the continuing saga of a Tektronix 545 scope. Soon to be working perfectly after I solve this one last problem, or so I think it's the last problem.
::::::
::::::Thanks,
::::::
::::::Dave
::::::
:::::
::::
:::
::
:
marv
:Marv,
: I looked very closely at the connector on the module and it looks almost perfect and the fingers are still shiny. I also inspected the receptacle on the scope end and found what looked like a hair inside but that wasn't a conductor. I can find nothing else. I don't see any cracks in the blue plastic. It is a little loose but I don't see how that could be a problem. I think it's supposed to be able to move a little bit.
: I have another plug-in but all the tubes are missing. When I plug that one in, it's a type D, there is no load no matter how many times I plug it in and plug it out. The resistance on pin 10 of the type D is 6K ohms. It doesn't matter if it's plugged in or not it stays 6K ohms. Not so for the type CA plug in unit. The moment it's plugged in the resistance goes down to 124 ohms. It makes no sense at all. I think I have checked everything and tested the tubes in the CA. All test very good.
:
:Thanks,
:
:Dave
:
::Dave,
::If I remember correctly from my last use of a Tek 545 (60's), those plug-in and mating connectors were blue, (AMP comes to mind) and when being mated caused a wiping action and some displacement of the contacts. One or both also float to ease alignment when mating. If the main body or even the plug-in frame is slightly torqued, the float mechanism may cause a short to frame. Closely inspect both connector bodies for cracks that would allow distortion and possible pin movement at mating. Is it possible that a small hair of wire/solder blob is buried inside the connector body, and when mated/displaced pin is shorting to another pin?
::
::marv
::
:::Johnnysan,
::: I just traced the 100 volt line and there are no loads when the plug-in is disconnected from the scope. There is none in the scope to be found and none in the plug in. Once they are connected there is 124 ohms on the 100 volt line. When they are detached there is 500 K ohms on the 100 volt line in the scope and 2 K ohms in the module. Why does it go way down when they are mated? Where does this load go when the module is unplugged from the scope?
:::That has been my question all along. How can I find a load that's not there? What's going on here? This is very strange and extremely frustrating.
:::
:::Thanks,
:::
:::Dave
:::
::::Just trace the 100 volt line through on the CA. If it's a heavy load, it will be a capacitor or tube. I'm not familiar with the CA; does it use transistors? The BAMA site has it in DJVU, which I can't open. Just put an ohmmeter on the line and start pulling tubes.
::::Johnnysan-
::::
::::
:::::Hello Again,
::::: There must be something inside the scope that is connecting when the module is plugged into the scope. But what? I don't think that the scope is possesed or anything. I don't see anythign awry with the connectors.
:::::
:::::It has to be something. If anyone has any ideas, please help. If I find the culprit, I'll let everyone know what it is.
:::::
:::::Thanks,
:::::
:::::Dave
::::::Hello Again,
:::::: Pin 8 is not where the problem is. It's probably pin 10 or with the plug-in module connector. Try as I might to find the problem, it doesn't exist. However when the module is plugged in there's a heavy load on the 100 v line. When the plug-in unit is plugged out, there is no such load.
:::::: I can find no such load in the plug-in. I measure 6K ohms on pin 10. The only place there is a low resistance is on pins 2 and 8. I can see no problems with the plug or jack part of the connector. What's going on here? This makes not sense and it's extremely frustrating.
::::::
::::::Thanks,
::::::
::::::Dave
:::::::Hello All,
::::::: Now that I got the HV tubes right and I did see them light up, But then the type CA module crapped out again, causing a resistor inside the scope to burn again and smoke and destroy itself this time. I have replaced it (NOS so nobody would ever know that it was ever replaced) and all is probably well inside the scope but I wont turn it on again until I solve this problem. Pin 8 on the module measures 2.5 ohms to the chassis. At first I thought it was the .005 mf capacitor but that's fine. I'm not sure if the 2.5 ohms is correct or not. I will now refer to the Type CA service data.
:::::::
:::::::This is the continuing saga of a Tektronix 545 scope. Soon to be working perfectly after I solve this one last problem, or so I think it's the last problem.
:::::::
:::::::Thanks,
:::::::
:::::::Dave
:::::::
::::::
:::::
::::
:::
::
:
Thanks,
Dave
:Dave,
:Is there another pin in either main body or plug-in near the suspect that might be known to have a 124 ohm measurement? Try deflecting the suspect with your meter probe while measuring and deflect other contacts near by with a non conductive instrument. Have you traced the suspect contact wiring in the plug-in to it's final destination?
:
:marv
:
::Marv,
:: I looked very closely at the connector on the module and it looks almost perfect and the fingers are still shiny. I also inspected the receptacle on the scope end and found what looked like a hair inside but that wasn't a conductor. I can find nothing else. I don't see any cracks in the blue plastic. It is a little loose but I don't see how that could be a problem. I think it's supposed to be able to move a little bit.
:: I have another plug-in but all the tubes are missing. When I plug that one in, it's a type D, there is no load no matter how many times I plug it in and plug it out. The resistance on pin 10 of the type D is 6K ohms. It doesn't matter if it's plugged in or not it stays 6K ohms. Not so for the type CA plug in unit. The moment it's plugged in the resistance goes down to 124 ohms. It makes no sense at all. I think I have checked everything and tested the tubes in the CA. All test very good.
::
::Thanks,
::
::Dave
::
:::Dave,
:::If I remember correctly from my last use of a Tek 545 (60's), those plug-in and mating connectors were blue, (AMP comes to mind) and when being mated caused a wiping action and some displacement of the contacts. One or both also float to ease alignment when mating. If the main body or even the plug-in frame is slightly torqued, the float mechanism may cause a short to frame. Closely inspect both connector bodies for cracks that would allow distortion and possible pin movement at mating. Is it possible that a small hair of wire/solder blob is buried inside the connector body, and when mated/displaced pin is shorting to another pin?
:::
:::marv
:::
::::Johnnysan,
:::: I just traced the 100 volt line and there are no loads when the plug-in is disconnected from the scope. There is none in the scope to be found and none in the plug in. Once they are connected there is 124 ohms on the 100 volt line. When they are detached there is 500 K ohms on the 100 volt line in the scope and 2 K ohms in the module. Why does it go way down when they are mated? Where does this load go when the module is unplugged from the scope?
::::That has been my question all along. How can I find a load that's not there? What's going on here? This is very strange and extremely frustrating.
::::
::::Thanks,
::::
::::Dave
::::
:::::Just trace the 100 volt line through on the CA. If it's a heavy load, it will be a capacitor or tube. I'm not familiar with the CA; does it use transistors? The BAMA site has it in DJVU, which I can't open. Just put an ohmmeter on the line and start pulling tubes.
:::::Johnnysan-
:::::
:::::
::::::Hello Again,
:::::: There must be something inside the scope that is connecting when the module is plugged into the scope. But what? I don't think that the scope is possesed or anything. I don't see anythign awry with the connectors.
::::::
::::::It has to be something. If anyone has any ideas, please help. If I find the culprit, I'll let everyone know what it is.
::::::
::::::Thanks,
::::::
::::::Dave
:::::::Hello Again,
::::::: Pin 8 is not where the problem is. It's probably pin 10 or with the plug-in module connector. Try as I might to find the problem, it doesn't exist. However when the module is plugged in there's a heavy load on the 100 v line. When the plug-in unit is plugged out, there is no such load.
::::::: I can find no such load in the plug-in. I measure 6K ohms on pin 10. The only place there is a low resistance is on pins 2 and 8. I can see no problems with the plug or jack part of the connector. What's going on here? This makes not sense and it's extremely frustrating.
:::::::
:::::::Thanks,
:::::::
:::::::Dave
::::::::Hello All,
:::::::: Now that I got the HV tubes right and I did see them light up, But then the type CA module crapped out again, causing a resistor inside the scope to burn again and smoke and destroy itself this time. I have replaced it (NOS so nobody would ever know that it was ever replaced) and all is probably well inside the scope but I wont turn it on again until I solve this problem. Pin 8 on the module measures 2.5 ohms to the chassis. At first I thought it was the .005 mf capacitor but that's fine. I'm not sure if the 2.5 ohms is correct or not. I will now refer to the Type CA service data.
::::::::
::::::::This is the continuing saga of a Tektronix 545 scope. Soon to be working perfectly after I solve this one last problem, or so I think it's the last problem.
::::::::
::::::::Thanks,
::::::::
::::::::Dave
::::::::
:::::::
::::::
:::::
::::
:::
::
:
:Marv,
: If the plug in is not plugged in I can trace it all the way and there is NO LOAD AT ALL. If it's plugged in there is a load everywhere in the 100 v line. I haven't tried pusing down the fingers in the scope to see if I can create the load. But as I said before, when I plug in the type D plug in there is NEVER a load. But I'm going to need a lot of 12AU7s to get that to work because they are all missing. I'll try this as soon as I have that relay all cleaned and the delayed turn on system works every time I turn it on. I'm sure I can turn on the scope without any plug in.
:
:Thanks,
:
:Dave
::Dave,
::Is there another pin in either main body or plug-in near the suspect that might be known to have a 124 ohm measurement? Try deflecting the suspect with your meter probe while measuring and deflect other contacts near by with a non conductive instrument. Have you traced the suspect contact wiring in the plug-in to it's final destination?
::
::marv
::
:::Marv,
::: I looked very closely at the connector on the module and it looks almost perfect and the fingers are still shiny. I also inspected the receptacle on the scope end and found what looked like a hair inside but that wasn't a conductor. I can find nothing else. I don't see any cracks in the blue plastic. It is a little loose but I don't see how that could be a problem. I think it's supposed to be able to move a little bit.
::: I have another plug-in but all the tubes are missing. When I plug that one in, it's a type D, there is no load no matter how many times I plug it in and plug it out. The resistance on pin 10 of the type D is 6K ohms. It doesn't matter if it's plugged in or not it stays 6K ohms. Not so for the type CA plug in unit. The moment it's plugged in the resistance goes down to 124 ohms. It makes no sense at all. I think I have checked everything and tested the tubes in the CA. All test very good.
:::
:::Thanks,
:::
:::Dave
:::
::::Dave,
::::If I remember correctly from my last use of a Tek 545 (60's), those plug-in and mating connectors were blue, (AMP comes to mind) and when being mated caused a wiping action and some displacement of the contacts. One or both also float to ease alignment when mating. If the main body or even the plug-in frame is slightly torqued, the float mechanism may cause a short to frame. Closely inspect both connector bodies for cracks that would allow distortion and possible pin movement at mating. Is it possible that a small hair of wire/solder blob is buried inside the connector body, and when mated/displaced pin is shorting to another pin?
::::
::::marv
::::
:::::Johnnysan,
::::: I just traced the 100 volt line and there are no loads when the plug-in is disconnected from the scope. There is none in the scope to be found and none in the plug in. Once they are connected there is 124 ohms on the 100 volt line. When they are detached there is 500 K ohms on the 100 volt line in the scope and 2 K ohms in the module. Why does it go way down when they are mated? Where does this load go when the module is unplugged from the scope?
:::::That has been my question all along. How can I find a load that's not there? What's going on here? This is very strange and extremely frustrating.
:::::
:::::Thanks,
:::::
:::::Dave
:::::
::::::Just trace the 100 volt line through on the CA. If it's a heavy load, it will be a capacitor or tube. I'm not familiar with the CA; does it use transistors? The BAMA site has it in DJVU, which I can't open. Just put an ohmmeter on the line and start pulling tubes.
::::::Johnnysan-
::::::
::::::
:::::::Hello Again,
::::::: There must be something inside the scope that is connecting when the module is plugged into the scope. But what? I don't think that the scope is possesed or anything. I don't see anythign awry with the connectors.
:::::::
:::::::It has to be something. If anyone has any ideas, please help. If I find the culprit, I'll let everyone know what it is.
:::::::
:::::::Thanks,
:::::::
:::::::Dave
::::::::Hello Again,
:::::::: Pin 8 is not where the problem is. It's probably pin 10 or with the plug-in module connector. Try as I might to find the problem, it doesn't exist. However when the module is plugged in there's a heavy load on the 100 v line. When the plug-in unit is plugged out, there is no such load.
:::::::: I can find no such load in the plug-in. I measure 6K ohms on pin 10. The only place there is a low resistance is on pins 2 and 8. I can see no problems with the plug or jack part of the connector. What's going on here? This makes not sense and it's extremely frustrating.
::::::::
::::::::Thanks,
::::::::
::::::::Dave
:::::::::Hello All,
::::::::: Now that I got the HV tubes right and I did see them light up, But then the type CA module crapped out again, causing a resistor inside the scope to burn again and smoke and destroy itself this time. I have replaced it (NOS so nobody would ever know that it was ever replaced) and all is probably well inside the scope but I wont turn it on again until I solve this problem. Pin 8 on the module measures 2.5 ohms to the chassis. At first I thought it was the .005 mf capacitor but that's fine. I'm not sure if the 2.5 ohms is correct or not. I will now refer to the Type CA service data.
:::::::::
:::::::::This is the continuing saga of a Tektronix 545 scope. Soon to be working perfectly after I solve this one last problem, or so I think it's the last problem.
:::::::::
:::::::::Thanks,
:::::::::
:::::::::Dave
:::::::::
::::::::
:::::::
::::::
:::::
::::
:::
::
:
Thanks,
Dave
:If you say the 124 ohm load is not present with another plug-in, then that CA must be the problem, or the 100 volt line loops through the CA contacts to another part of the scope. Has it been modified in any way? Components changed?
:Johnnysan-
:
:
:
:
::Marv,
:: If the plug in is not plugged in I can trace it all the way and there is NO LOAD AT ALL. If it's plugged in there is a load everywhere in the 100 v line. I haven't tried pusing down the fingers in the scope to see if I can create the load. But as I said before, when I plug in the type D plug in there is NEVER a load. But I'm going to need a lot of 12AU7s to get that to work because they are all missing. I'll try this as soon as I have that relay all cleaned and the delayed turn on system works every time I turn it on. I'm sure I can turn on the scope without any plug in.
::
::Thanks,
::
::Dave
:::Dave,
:::Is there another pin in either main body or plug-in near the suspect that might be known to have a 124 ohm measurement? Try deflecting the suspect with your meter probe while measuring and deflect other contacts near by with a non conductive instrument. Have you traced the suspect contact wiring in the plug-in to it's final destination?
:::
:::marv
:::
::::Marv,
:::: I looked very closely at the connector on the module and it looks almost perfect and the fingers are still shiny. I also inspected the receptacle on the scope end and found what looked like a hair inside but that wasn't a conductor. I can find nothing else. I don't see any cracks in the blue plastic. It is a little loose but I don't see how that could be a problem. I think it's supposed to be able to move a little bit.
:::: I have another plug-in but all the tubes are missing. When I plug that one in, it's a type D, there is no load no matter how many times I plug it in and plug it out. The resistance on pin 10 of the type D is 6K ohms. It doesn't matter if it's plugged in or not it stays 6K ohms. Not so for the type CA plug in unit. The moment it's plugged in the resistance goes down to 124 ohms. It makes no sense at all. I think I have checked everything and tested the tubes in the CA. All test very good.
::::
::::Thanks,
::::
::::Dave
::::
:::::Dave,
:::::If I remember correctly from my last use of a Tek 545 (60's), those plug-in and mating connectors were blue, (AMP comes to mind) and when being mated caused a wiping action and some displacement of the contacts. One or both also float to ease alignment when mating. If the main body or even the plug-in frame is slightly torqued, the float mechanism may cause a short to frame. Closely inspect both connector bodies for cracks that would allow distortion and possible pin movement at mating. Is it possible that a small hair of wire/solder blob is buried inside the connector body, and when mated/displaced pin is shorting to another pin?
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:::::marv
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::::::Johnnysan,
:::::: I just traced the 100 volt line and there are no loads when the plug-in is disconnected from the scope. There is none in the scope to be found and none in the plug in. Once they are connected there is 124 ohms on the 100 volt line. When they are detached there is 500 K ohms on the 100 volt line in the scope and 2 K ohms in the module. Why does it go way down when they are mated? Where does this load go when the module is unplugged from the scope?
::::::That has been my question all along. How can I find a load that's not there? What's going on here? This is very strange and extremely frustrating.
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::::::Thanks,
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::::::Dave
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:::::::Just trace the 100 volt line through on the CA. If it's a heavy load, it will be a capacitor or tube. I'm not familiar with the CA; does it use transistors? The BAMA site has it in DJVU, which I can't open. Just put an ohmmeter on the line and start pulling tubes.
:::::::Johnnysan-
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:::::::
::::::::Hello Again,
:::::::: There must be something inside the scope that is connecting when the module is plugged into the scope. But what? I don't think that the scope is possesed or anything. I don't see anythign awry with the connectors.
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::::::::It has to be something. If anyone has any ideas, please help. If I find the culprit, I'll let everyone know what it is.
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::::::::Thanks,
::::::::
::::::::Dave
:::::::::Hello Again,
::::::::: Pin 8 is not where the problem is. It's probably pin 10 or with the plug-in module connector. Try as I might to find the problem, it doesn't exist. However when the module is plugged in there's a heavy load on the 100 v line. When the plug-in unit is plugged out, there is no such load.
::::::::: I can find no such load in the plug-in. I measure 6K ohms on pin 10. The only place there is a low resistance is on pins 2 and 8. I can see no problems with the plug or jack part of the connector. What's going on here? This makes not sense and it's extremely frustrating.
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:::::::::Thanks,
:::::::::
:::::::::Dave
::::::::::Hello All,
:::::::::: Now that I got the HV tubes right and I did see them light up, But then the type CA module crapped out again, causing a resistor inside the scope to burn again and smoke and destroy itself this time. I have replaced it (NOS so nobody would ever know that it was ever replaced) and all is probably well inside the scope but I wont turn it on again until I solve this problem. Pin 8 on the module measures 2.5 ohms to the chassis. At first I thought it was the .005 mf capacitor but that's fine. I'm not sure if the 2.5 ohms is correct or not. I will now refer to the Type CA service data.
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::::::::::This is the continuing saga of a Tektronix 545 scope. Soon to be working perfectly after I solve this one last problem, or so I think it's the last problem.
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::::::::::Thanks,
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::::::::::Dave
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