A section output...16v
B section output
0v....should be 22v
.1v....should be 45v
.1v....should be 67v
.1v....should be 90v
49.8v....should be 135v
Regards
Job
How does the supply get those lower voltages? If Zener diodes are used be sure polarity is correct. With Zener diodes reversed you will have very little voltage. Measure across Zener diodes to be sure they aren't shorted.
Norm
:I purchased a K-101A Battery Eliminator Kit some time back and assemblied it. However, I am not receiving the output voltage called for. I talked to a tech from this company and he sent me a bridge rectifier to replace the one which he thought could be faulty. However,nothing as changed and I'm still receiving the same distorted voltages. I am hoping that some of you may have experienced problems with this unit and may have some suggestions for me. I can scan and send the schematic if anyone requires it.
:This is the readings I am receiving with the variable voltages at its maximum.
:
:A section output...16v
:
:B section output
: 0v....should be 22v
: .1v....should be 45v
: .1v....should be 67v
: .1v....should be 90v
: 49.8v....should be 135v
:
:Regards
:
:Job
:
:
:
:
:Hi Job
:
: How does the supply get those lower voltages? If Zener diodes are used be sure polarity is correct. With Zener diodes reversed you will have very little voltage. Measure across Zener diodes to be sure they aren't shorted.
:
:Norm
:
::I purchased a K-101A Battery Eliminator Kit some time back and assemblied it. However, I am not receiving the output voltage called for. I talked to a tech from this company and he sent me a bridge rectifier to replace the one which he thought could be faulty. However,nothing as changed and I'm still receiving the same distorted voltages. I am hoping that some of you may have experienced problems with this unit and may have some suggestions for me. I can scan and send the schematic if anyone requires it.
::This is the readings I am receiving with the variable voltages at its maximum.
::
::A section output...16v
::
::B section output
:: 0v....should be 22v
:: .1v....should be 45v
:: .1v....should be 67v
:: .1v....should be 90v
:: 49.8v....should be 135v
::
::Regards
::
::Job
::
::
::
::
You may want to check out Doug Criner's thoughts and observations of the K-101A kit at:
http://www.enginova.com/batt_elim.htm
Radiodoc
**************
:Norm....I forgot to give the reading for the C section which is 48.5v. I will check the Zener diodes and get back to you later.
:Job
:
:
:
::Hi Job
::
:: How does the supply get those lower voltages? If Zener diodes are used be sure polarity is correct. With Zener diodes reversed you will have very little voltage. Measure across Zener diodes to be sure they aren't shorted.
::
::Norm
::
:::I purchased a K-101A Battery Eliminator Kit some time back and assemblied it. However, I am not receiving the output voltage called for. I talked to a tech from this company and he sent me a bridge rectifier to replace the one which he thought could be faulty. However,nothing as changed and I'm still receiving the same distorted voltages. I am hoping that some of you may have experienced problems with this unit and may have some suggestions for me. I can scan and send the schematic if anyone requires it.
:::This is the readings I am receiving with the variable voltages at its maximum.
:::
:::A section output...16v
:::
:::B section output
::: 0v....should be 22v
::: .1v....should be 45v
::: .1v....should be 67v
::: .1v....should be 90v
::: 49.8v....should be 135v
:::
:::Regards
:::
:::Job
:::
:::
:::
:::
:Job,
:
:You may want to check out Doug Criner's thoughts and observations of the K-101A kit at:
:
:http://www.enginova.com/batt_elim.htm
:
:Radiodoc
:**************
:
::Norm....I forgot to give the reading for the C section which is 48.5v. I will check the Zener diodes and get back to you later.
::Job
::
::
::
:::Hi Job
:::
::: How does the supply get those lower voltages? If Zener diodes are used be sure polarity is correct. With Zener diodes reversed you will have very little voltage. Measure across Zener diodes to be sure they aren't shorted.
:::
:::Norm
:::
::::I purchased a K-101A Battery Eliminator Kit some time back and assemblied it. However, I am not receiving the output voltage called for. I talked to a tech from this company and he sent me a bridge rectifier to replace the one which he thought could be faulty. However,nothing as changed and I'm still receiving the same distorted voltages. I am hoping that some of you may have experienced problems with this unit and may have some suggestions for me. I can scan and send the schematic if anyone requires it.
::::This is the readings I am receiving with the variable voltages at its maximum.
::::
::::A section output...16v
::::
::::B section output
:::: 0v....should be 22v
:::: .1v....should be 45v
:::: .1v....should be 67v
:::: .1v....should be 90v
:::: 49.8v....should be 135v
::::
::::Regards
::::
::::Job
::::
::::
::::
::::
I didn't specifically interpret, as to whether the kit put out the proper voltages "back" when you got it or if you were now just completing the unit and found those voltage discreptancies.
Referring to the units B supply circuitry:
http://img130.imageshack.us/img130/6823/untitledha9.png
The voltage readings suggest that your very top two series zener regulator /divider string diodes are doing you right, but that the string below it are shorted out. (With the alternate possible exception of the metering that you were using was not reading out enough accuracy to differentiate the low voltage drop of a diode junction...~.6-.7 VDC.. and it was not being caught.) Even if a person was to wire that lower string in with backwards polarity, even then, an ~2.8 VDC reading would be presented at the +90 V juncture. The only other thought on failure would for an inductive load to have been connected to the 90 V point and one VERY... VERY...B-O-D-A-C-I-O-U-S inductive kick back having been presented to that point.
73's de Edd
First, check the DC voltage across the filter cap, C1. It should be about 165V or so. If that voltage is OK, then the problem must be downstream from there, e.g., the transistor regulators, zeners, etc.
Doug
:Job, check the B+ supply voltages in a systematic manner, and you should be able to pinpoint the problem.
:
:First, check the DC voltage across the filter cap, C1. It should be about 165V or so. If that voltage is OK, then the problem must be downstream from there, e.g., the transistor regulators, zeners, etc.
:Doug
Here is a troubleshooting suggestion: temporarily jumper between C and E of Q1, and see if the B voltages come up to where they belong. If they do, you might want to consider the mods described in my website. That does away with the regulators altogether, resulting in a simpler circuit that works fine.
Doug
:I have checked for shorts and polarity and can't seem to come up with anything wrong. However, I can only seem to get a resistant reading on one side of the transistor, Q1..1520 ohms. The diodes all have readings of approximately 10.5k ohms. Voltage reading across capacitor C1 is 186v--C2 is 104v, and C5 is 24v. Maybe some of you can suggest other voltages/resistances, etc., that I should be checking. If so, be specific because my smarts are limited when it comes to those circuits.
:Thanks
:Job
:
:
::Job, check the B+ supply voltages in a systematic manner, and you should be able to pinpoint the problem.
::
::First, check the DC voltage across the filter cap, C1. It should be about 165V or so. If that voltage is OK, then the problem must be downstream from there, e.g., the transistor regulators, zeners, etc.
::Doug
http://img514.imageshack.us/img514/3909/pskitel4.jpg
Well it looks like we know that either Q1 is conducting OR there is a series static...not necessarily dynamic ! voltage currently at its emitter. First lets fire up the unit and take a DCV voltage reading at that Q1 emittr and then place an ~470ohm <----->1k ohm resistor to ground and see what happens to our 49.8 voltage level.
Log down the loaded voltage for future ref.
Take the the loading resistor out of circuit and set aside.
Now, move down to the emitter referencing threshold zener diode D14 and give us the voltage reading across it.
Then move up to the base of Q2 and take the voltage read across it..of course.... all voltages are referenced with - metering probe to ground.
ZUJ'ing ..... for the m-a-g-i-c-a-l numbers now.
73's de Edd
Base of Q1 is 24 volts. Collector is 104 volts or more. Emitter will follow base. Would expect it to be close to 24 volts not 49.8. Any chance there is a wiring error with Q1?
Here is another thing to think about. Since the 135 output has 49.8 volts why doesn't 90 have something? 135-90 = 45. 49.8 should make the 90 supply around 5 volts.
Check diodes D4-D7. It's not a good idea to use Zener diodes like in this power supply. If capacitors are used on the output voltages and any leads are shorted Zeners will blow. Not like tubes. This happens instantly.
Norm
:I put all to date voltage readings and info and the units (A-version) schematic at one worksheet site at:
:
:http://img514.imageshack.us/img514/3909/pskitel4.jpg
:
:Well it looks like we know that either Q1 is conducting OR there is a series static...not necessarily dynamic ! voltage currently at its emitter. First lets fire up the unit and take a DCV voltage reading at that Q1 emittr and then place an ~470ohm <----->1k ohm resistor to ground and see what happens to our 49.8 voltage level.
:Log down the loaded voltage for future ref.
:Take the the loading resistor out of circuit and set aside.
:Now, move down to the emitter referencing threshold zener diode D14 and give us the voltage reading across it.
:Then move up to the base of Q2 and take the voltage read across it..of course.... all voltages are referenced with - metering probe to ground.
:ZUJ'ing ..... for the m-a-g-i-c-a-l numbers now.
:
:73's de Edd
:
A+--7.7v
C+--22.4v
B+22--0v
B+45--0v
B+67--0v
B+90--0v
B+135-23v
Doug, my multimeter does not check diode functions so I have no idea what those readings meant, if anything. I did place a jumper between C and E of Q1 and slowly increased my voltage but I saw smoke curling up before getting up to maximum voltage. I shut down real fast.
Edd, I placed a 470 ohm resistor in the circuit re your instructions...emitter of Q1 to ground.. but received the same voltage as without it....23v.
The other readings are as follows:
Q1-E..23v Q1-B..23.5v Q1-C..181v
Q14-E..23.2v Q14-B..0v Q14-C..23.5v
Doug, maybe I'll have to try your suggestions re modifications if we can't figure out what is going on here.
Regards
Job
:Follow Edd's suggestions but there is a problem at Q1.
:
:Base of Q1 is 24 volts. Collector is 104 volts or more. Emitter will follow base. Would expect it to be close to 24 volts not 49.8. Any chance there is a wiring error with Q1?
:
:Here is another thing to think about. Since the 135 output has 49.8 volts why doesn't 90 have something? 135-90 = 45. 49.8 should make the 90 supply around 5 volts.
:
:Check diodes D4-D7. It's not a good idea to use Zener diodes like in this power supply. If capacitors are used on the output voltages and any leads are shorted Zeners will blow. Not like tubes. This happens instantly.
:
:Norm
:
:
::I put all to date voltage readings and info and the units (A-version) schematic at one worksheet site at:
::
::http://img514.imageshack.us/img514/3909/pskitel4.jpg
::
::Well it looks like we know that either Q1 is conducting OR there is a series static...not necessarily dynamic ! voltage currently at its emitter. First lets fire up the unit and take a DCV voltage reading at that Q1 emittr and then place an ~470ohm <----->1k ohm resistor to ground and see what happens to our 49.8 voltage level.
::Log down the loaded voltage for future ref.
::Take the the loading resistor out of circuit and set aside.
::Now, move down to the emitter referencing threshold zener diode D14 and give us the voltage reading across it.
::Then move up to the base of Q2 and take the voltage read across it..of course.... all voltages are referenced with - metering probe to ground.
::ZUJ'ing ..... for the m-a-g-i-c-a-l numbers now.
::
::73's de Edd
::
Voltages are now reasonable except for base of Q1. What is drawing it down to 24 volts? Q2 may be leaky? Lifting the collector wire on this transistor might allow full voltage out? Cap C5 could be bad or rated for low voltage?
Believe what you list as Q14 is Q2? D14 is by this transistor.
Norm
:Gentlemen------Let me correct misleading readings re the B+ power supply of this unit. I was reading AC current and not DC...gees, I'm blushing here...The correct readings are as folows:
:
:A+--7.7v
:C+--22.4v
:B+22--0v
:B+45--0v
:B+67--0v
:B+90--0v
:B+135-23v
:
:Doug, my multimeter does not check diode functions so I have no idea what those readings meant, if anything. I did place a jumper between C and E of Q1 and slowly increased my voltage but I saw smoke curling up before getting up to maximum voltage. I shut down real fast.
:
:Edd, I placed a 470 ohm resistor in the circuit re your instructions...emitter of Q1 to ground.. but received the same voltage as without it....23v.
:
:The other readings are as follows:
:
:Q1-E..23v Q1-B..23.5v Q1-C..181v
:
:Q14-E..23.2v Q14-B..0v Q14-C..23.5v
:
:Doug, maybe I'll have to try your suggestions re modifications if we can't figure out what is going on here.
:
:Regards
:
:Job
:
:
:
:
:
::Follow Edd's suggestions but there is a problem at Q1.
::
::Base of Q1 is 24 volts. Collector is 104 volts or more. Emitter will follow base. Would expect it to be close to 24 volts not 49.8. Any chance there is a wiring error with Q1?
::
::Here is another thing to think about. Since the 135 output has 49.8 volts why doesn't 90 have something? 135-90 = 45. 49.8 should make the 90 supply around 5 volts.
::
::Check diodes D4-D7. It's not a good idea to use Zener diodes like in this power supply. If capacitors are used on the output voltages and any leads are shorted Zeners will blow. Not like tubes. This happens instantly.
::
::Norm
::
::
:::I put all to date voltage readings and info and the units (A-version) schematic at one worksheet site at:
:::
:::http://img514.imageshack.us/img514/3909/pskitel4.jpg
:::
:::Well it looks like we know that either Q1 is conducting OR there is a series static...not necessarily dynamic ! voltage currently at its emitter. First lets fire up the unit and take a DCV voltage reading at that Q1 emittr and then place an ~470ohm <----->1k ohm resistor to ground and see what happens to our 49.8 voltage level.
:::Log down the loaded voltage for future ref.
:::Take the the loading resistor out of circuit and set aside.
:::Now, move down to the emitter referencing threshold zener diode D14 and give us the voltage reading across it.
:::Then move up to the base of Q2 and take the voltage read across it..of course.... all voltages are referenced with - metering probe to ground.
:::ZUJ'ing ..... for the m-a-g-i-c-a-l numbers now.
:::
:::73's de Edd
:::
:Job
:
: Voltages are now reasonable except for base of Q1. What is drawing it down to 24 volts? Q2 may be leaky? Lifting the collector wire on this transistor might allow full voltage out? Cap C5 could be bad or rated for low voltage?
:
: Believe what you list as Q14 is Q2? D14 is by this transistor.
:
:Norm
:
:
:
:
:
::Gentlemen------Let me correct misleading readings re the B+ power supply of this unit. I was reading AC current and not DC...gees, I'm blushing here...The correct readings are as folows:
::
::A+--7.7v
::C+--22.4v
::B+22--0v
::B+45--0v
::B+67--0v
::B+90--0v
::B+135-23v
::
::Doug, my multimeter does not check diode functions so I have no idea what those readings meant, if anything. I did place a jumper between C and E of Q1 and slowly increased my voltage but I saw smoke curling up before getting up to maximum voltage. I shut down real fast.
::
::Edd, I placed a 470 ohm resistor in the circuit re your instructions...emitter of Q1 to ground.. but received the same voltage as without it....23v.
::
::The other readings are as follows:
::
::Q1-E..23v Q1-B..23.5v Q1-C..181v
::
::Q14-E..23.2v Q14-B..0v Q14-C..23.5v
::
::Doug, maybe I'll have to try your suggestions re modifications if we can't figure out what is going on here.
::
::Regards
::
::Job
::
::
::
::
::
:::Follow Edd's suggestions but there is a problem at Q1.
:::
:::Base of Q1 is 24 volts. Collector is 104 volts or more. Emitter will follow base. Would expect it to be close to 24 volts not 49.8. Any chance there is a wiring error with Q1?
:::
:::Here is another thing to think about. Since the 135 output has 49.8 volts why doesn't 90 have something? 135-90 = 45. 49.8 should make the 90 supply around 5 volts.
:::
:::Check diodes D4-D7. It's not a good idea to use Zener diodes like in this power supply. If capacitors are used on the output voltages and any leads are shorted Zeners will blow. Not like tubes. This happens instantly.
:::
:::Norm
:::
:::
::::I put all to date voltage readings and info and the units (A-version) schematic at one worksheet site at:
::::
::::http://img514.imageshack.us/img514/3909/pskitel4.jpg
::::
::::Well it looks like we know that either Q1 is conducting OR there is a series static...not necessarily dynamic ! voltage currently at its emitter. First lets fire up the unit and take a DCV voltage reading at that Q1 emittr and then place an ~470ohm <----->1k ohm resistor to ground and see what happens to our 49.8 voltage level.
::::Log down the loaded voltage for future ref.
::::Take the the loading resistor out of circuit and set aside.
::::Now, move down to the emitter referencing threshold zener diode D14 and give us the voltage reading across it.
::::Then move up to the base of Q2 and take the voltage read across it..of course.... all voltages are referenced with - metering probe to ground.
::::ZUJ'ing ..... for the m-a-g-i-c-a-l numbers now.
::::
::::73's de Edd
::::
The voltage currently present on the emitter of power control xstr Q1 is right in order of the voltage present at the base of Q1 if it was shorted C-E and thus leaving the fixed base biasing initially derived from the loop of the collector of Q1 voltage level passing down thru R3 and then passing on thru R4 to provide the most bias required for the imstrument at its highest current demands. Simultaneously that voltage level at the collector of Q1 is passed thru Q1 to its emitter. That high voltage level is then dumped into a series arranged string
of zener diodes of D4-D5 D6-D6-D7-D8-D9-D10-D11-D12-D13 and finally little 'ole R5 ...yelling.. me too...ME TOO.....down there at the very bottom of the string and completing the loop to ground.
Had your instrument been operating to spec, the top voltage would have been adequate to have had enough voltage across the TOTAL string to create voltage nodes at ALL of the specified tap off points with little R5 there, along with his brother R8 forming a divider bridge and channeling base bias voltage over to Q2. Now, that function is associated with the regulation of the circuit. If the voltage sampled across R5 is getting excessive and wanting to go up above that 22V threshold, D4 a 22 V Zener diode will start conducting in response to that higher voltage presented by R8/R5 and then base drive presented to Q2 will make it conduct from its collector and thru to its emitter and then into and thru that conducting D14 and complete a ground loop. What is this conduction then doing? ....why it is robbing the initially established static base bias away from Q1 and shunting it off to ground thru the Q2-D14 series pair. You remember, I initially said
that degree of base bias establishes the output level of Q1...so now it has been throttled back on , with the diode string receiving less now, the voltage developed across R5 has diminished down to the point wher it is no longer triggering Q2 to regulate the voltage down....so now...all is back to the norm.
Aside...assuming that the calamity derived from the use af a VARIAC on the AC line and having Q1 jumpered and the resultant....'moke,
'moke..... I SMELL 'MOKE....was probably the coating or surface of R1 heating , hopefully with no electrical damage done...just your nerves.
In your taking of the reading that I specified using a bit of loading, lets us know that reading is not an insignificant miniscule level of static voltage.
Will mull over the readings last given ... re do the work sheet ...and come back with testing info.
For now....
73's de Edd
Lewis L
Q1..E-175v; Q1..B-177v; Q1..C-181v
Q2..E-0v; Q2..B-73v; Q2..C-177v
B+22..72v; B+45..94v; B+67..115v; B+90..137v; B+135..180v
I'm not sure what this all means but maybe someone can interrupt it.
Thanks
Job
::Job: If you're absolutely sure that the zener polarities are installed correctly, I'm suspecting the voltage regulator, Q1. Double check that it's installed correctly. (By the way, you can't really check a diode with an ohmmeter. Does your multimeter have a diode check function?)
::
::Here is a troubleshooting suggestion: temporarily jumper between C and E of Q1, and see if the B voltages come up to where they belong. If they do, you might want to consider the mods described in my website. That does away with the regulators altogether, resulting in a simpler circuit that works fine.
::Doug
:Hey, Doug, I checked your website concerning your mods,and I agree with you that the Zeners are pretty much Voltage regulators in themselves, so why connect a Voltage regulator to a Voltage regulator? Besides, the radios should be designed to work well as the batteries run down, so why would you need a super carefully regulated Voltage anyway?
:
:Lewis L
Believe Q2 is leaky or shorted emitter to collector. Check with an ohm meter.
Tranistor number isn't critical but needs to be NPN and high voltage rating. Can't quite read the original number but MPSA42 is rated 300 volts CE.
Norm
:I lifted the collector wire on Q2 as suggested by Norm and this is the results I receive now. All readings are from using B minus as ground....correct me if I'm doing this wrong.
:
:Q1..E-175v; Q1..B-177v; Q1..C-181v
:
:Q2..E-0v; Q2..B-73v; Q2..C-177v
:
:B+22..72v; B+45..94v; B+67..115v; B+90..137v; B+135..180v
:
:I'm not sure what this all means but maybe someone can interrupt it.
:Thanks
:
:Job
:
:
:
:
:
:::Job: If you're absolutely sure that the zener polarities are installed correctly, I'm suspecting the voltage regulator, Q1. Double check that it's installed correctly. (By the way, you can't really check a diode with an ohmmeter. Does your multimeter have a diode check function?)
:::
:::Here is a troubleshooting suggestion: temporarily jumper between C and E of Q1, and see if the B voltages come up to where they belong. If they do, you might want to consider the mods described in my website. That does away with the regulators altogether, resulting in a simpler circuit that works fine.
:::Doug
::Hey, Doug, I checked your website concerning your mods,and I agree with you that the Zeners are pretty much Voltage regulators in themselves, so why connect a Voltage regulator to a Voltage regulator? Besides, the radios should be designed to work well as the batteries run down, so why would you need a super carefully regulated Voltage anyway?
::
::Lewis L
The voltage currently present on the emitter of power control xstr Q1 is right in order of the voltage present at the base of Q1 if it was shorted C-E and thus leaving the fixed base biasing initially derived from the loop of the collector of Q1 voltage level passing down thru R3 and then passing on thru R4 to provide the most bias required for the imstrument at its highest current demands. Simultaneously that voltage level at the collector of Q1 is passed thru Q1 to its emitter. That high voltage level is then dumped into a series arranged string
of zener diodes of D4-D5 D6-D6-D7-D8-D9-D10-D11-D12-D13 and finally little 'ole R5 ...yelling.. me too...ME TOO.....down there at the very bottom of the string and completing the loop to ground.
Had your instrument been operating to spec, the top voltage would have been adequate to have had enough voltage across the TOTAL string to create voltage nodes at ALL of the specified tap off points with little R5 there, along with his brother R8 forming a divider bridge and channeling base bias voltage over to Q2. Now, that function is associated with the regulation of the circuit. If the voltage sampled across R5 is getting excessive and wanting to go up above that 22V threshold, D4 a 22 V Zener diode will start conducting in response to that higher voltage presented by R8/R5 and then base drive presented to Q2 will make it conduct from its collector and thru to its emitter and then into and thru that conducting D14 and complete a ground loop. What is this conduction then doing? ....why it is robbing the initially established static base bias away from Q1 and shunting it off to ground thru the Q2-D14 series pair. You remember, I initially said
that degree of base bias establishes the output level of Q1...so now it has been throttled back on , with the diode string receiving less now, the voltage developed across R5 has diminished down to the point wher it is no longer triggering Q2 to regulate the voltage down....so now...all is back to the norm.
Aside...assuming that the calamity derived from the use af a VARIAC on the AC line and having Q1 jumpered and the resultant....'moke,
'moke..... I SMELL 'MOKE....was probably the coating or surface of R1 heating , hopefully with no electrical damage done...just your nerves.
In your taking of the reading that I specified using a bit of loading, lets us know that reading is not an insignificant miniscule level of static voltage.
Will mull over the readings last given ... re do the work sheet ...and come back with testing info.
For now....
73's de Edd
This was a dupe, from just above, as I see that I was off from being at the very bottom of the string.
--------------------------------------------------------------B/T---------------------------------------------------------------------------
:Job
:
: Believe Q2 is leaky or shorted emitter to collector. Check with an ohm meter.
:
: Tranistor number isn't critical but needs to be NPN and high voltage rating. Can't quite read the original number but MPSA42 is rated 300 volts CE.
:
:Norm
:
::I lifted the collector wire on Q2 as suggested by Norm and this is the results I receive now. All readings are from using B minus as ground....correct me if I'm doing this wrong.
::
::Q1..E-175v; Q1..B-177v; Q1..C-181v
::
::Q2..E-0v; Q2..B-73v; Q2..C-177v
::
::B+22..72v; B+45..94v; B+67..115v; B+90..137v; B+135..180v
::
::I'm not sure what this all means but maybe someone can interrupt it.
::Thanks
::
::Job
::
::
::
::
::
::::Job: If you're absolutely sure that the zener polarities are installed correctly, I'm suspecting the voltage regulator, Q1. Double check that it's installed correctly. (By the way, you can't really check a diode with an ohmmeter. Does your multimeter have a diode check function?)
::::
::::Here is a troubleshooting suggestion: temporarily jumper between C and E of Q1, and see if the B voltages come up to where they belong. If they do, you might want to consider the mods described in my website. That does away with the regulators altogether, resulting in a simpler circuit that works fine.
::::Doug
:::Hey, Doug, I checked your website concerning your mods,and I agree with you that the Zeners are pretty much Voltage regulators in themselves, so why connect a Voltage regulator to a Voltage regulator? Besides, the radios should be designed to work well as the batteries run down, so why would you need a super carefully regulated Voltage anyway?
:::
:::Lewis L
73's de Edd
:--------------------------------------------------------------B/T---------------------------------------------------------------------------
::Job
::
:: Believe Q2 is leaky or shorted emitter to collector. Check with an ohm meter.
::
:: Tranistor number isn't critical but needs to be NPN and high voltage rating. Can't quite read the original number but MPSA42 is rated 300 volts CE.
::
::Norm
::
:::I lifted the collector wire on Q2 as suggested by Norm and this is the results I receive now. All readings are from using B minus as ground....correct me if I'm doing this wrong.
:::
:::Q1..E-175v; Q1..B-177v; Q1..C-181v
:::
:::Q2..E-0v; Q2..B-73v; Q2..C-177v
:::
:::B+22..72v; B+45..94v; B+67..115v; B+90..137v; B+135..180v
:::
:::I'm not sure what this all means but maybe someone can interrupt it.
:::Thanks
:::
:::Job
:::
:::
:::
:::
:::
:::::Job: If you're absolutely sure that the zener polarities are installed correctly, I'm suspecting the voltage regulator, Q1. Double check that it's installed correctly. (By the way, you can't really check a diode with an ohmmeter. Does your multimeter have a diode check function?)
:::::
:::::Here is a troubleshooting suggestion: temporarily jumper between C and E of Q1, and see if the B voltages come up to where they belong. If they do, you might want to consider the mods described in my website. That does away with the regulators altogether, resulting in a simpler circuit that works fine.
:::::Doug
::::Hey, Doug, I checked your website concerning your mods,and I agree with you that the Zeners are pretty much Voltage regulators in themselves, so why connect a Voltage regulator to a Voltage regulator? Besides, the radios should be designed to work well as the batteries run down, so why would you need a super carefully regulated Voltage anyway?
::::
::::Lewis L
Worksheet withthe new #'s:
http://img339.imageshack.us/img339/2402/newworksheetcd5.jpg
After checking the specs for the '42 its working at about 1/2 its specified specs in this circuitry...so...I believe that I may have ~20+ of them ...but not here to check on, and confirm.... so I will confirm tonight...and be able to send you a pair with one for a backup... or if I have yet a heftier substitute / upgrade, I will send that also.
On checking your "Job" name at the top of this page , I see that it is not "URL hot", sooo, on the next reply place include your E-mail addee also, just below your name in the box, so that I can then get a mailing addee from you to send the parts to.
73's de Edd
::--------------------------------------------------------------B/T---------------------------------------------------------------------------
:::Job
:::
::: Believe Q2 is leaky or shorted emitter to collector. Check with an ohm meter.
:::
::: Tranistor number isn't critical but needs to be NPN and high voltage rating. Can't quite read the original number but MPSA42 is rated 300 volts CE.
:::
:::Norm
:::
::::I lifted the collector wire on Q2 as suggested by Norm and this is the results I receive now. All readings are from using B minus as ground....correct me if I'm doing this wrong.
::::
::::Q1..E-175v; Q1..B-177v; Q1..C-181v
::::
::::Q2..E-0v; Q2..B-73v; Q2..C-177v
::::
::::B+22..72v; B+45..94v; B+67..115v; B+90..137v; B+135..180v
::::
::::I'm not sure what this all means but maybe someone can interrupt it.
::::Thanks
::::
::::Job
::::
::::
::::
::::
::::
::::::Job: If you're absolutely sure that the zener polarities are installed correctly, I'm suspecting the voltage regulator, Q1. Double check that it's installed correctly. (By the way, you can't really check a diode with an ohmmeter. Does your multimeter have a diode check function?)
::::::
::::::Here is a troubleshooting suggestion: temporarily jumper between C and E of Q1, and see if the B voltages come up to where they belong. If they do, you might want to consider the mods described in my website. That does away with the regulators altogether, resulting in a simpler circuit that works fine.
::::::Doug
:::::Hey, Doug, I checked your website concerning your mods,and I agree with you that the Zeners are pretty much Voltage regulators in themselves, so why connect a Voltage regulator to a Voltage regulator? Besides, the radios should be designed to work well as the batteries run down, so why would you need a super carefully regulated Voltage anyway?
:::::
:::::Lewis L
+135 is 135v
+90 is 93v
+67 is 71.8v
+45 is 50.4v
+22 is 29.3v
It appears that the voltage discripancy increases percentage wise as the voltage decreases.
Also, the E to C of Q2 reads 39 ohms..E to B no reading, and C to B no reading.
I don't know what any of this all means but I do believe with the help of you all we may be narrowing the problem to the transistor Q2, and Edd I don't have a replacement and would gladly purchase a one from you.
regards
Job
:::Sir Job
:::...the man with all of the patience...
:::
:::The voltage currently present on the emitter of power control xstr Q1 is right in order of the voltage present at the base of Q1 if it was shorted C-E and thus leaving the fixed base biasing initially derived from the loop of the collector of Q1 voltage level passing down thru R3 and then passing on thru R4 to provide the most bias required for the imstrument at its highest current demands. Simultaneously that voltage level at the collector of Q1 is passed thru Q1 to its emitter. That high voltage level is then dumped into a series arranged string
:::of zener diodes of D4-D5 D6-D6-D7-D8-D9-D10-D11-D12-D13 and finally little 'ole R5 ...yelling.. me too...ME TOO.....down there at the very bottom of the string and completing the loop to ground.
:::Had your instrument been operating to spec, the top voltage would have been adequate to have had enough voltage across the TOTAL string to create voltage nodes at ALL of the specified tap off points with little R5 there, along with his brother R8 forming a divider bridge and channeling base bias voltage over to Q2. Now, that function is associated with the regulation of the circuit. If the voltage sampled across R5 is getting excessive and wanting to go up above that 22V threshold, D4 a 22 V Zener diode will start conducting in response to that higher voltage presented by R8/R5 and then base drive presented to Q2 will make it conduct from its collector and thru to its emitter and then into and thru that conducting D14 and complete a ground loop. What is this conduction then doing? ....why it is robbing the initially established static base bias away from Q1 and shunting it off to ground thru the Q2-D14 series pair. You remember, I initially said
:::that degree of base bias establishes the output level of Q1...so now it has been throttled back on , with the diode string receiving less now, the voltage developed across R5 has diminished down to the point wher it is no longer triggering Q2 to regulate the voltage down....so now...all is back to the norm.
:::
:::Aside...assuming that the calamity derived from the use af a VARIAC on the AC line and having Q1 jumpered and the resultant....'moke,
:::'moke..... I SMELL 'MOKE....was probably the coating or surface of R1 heating , hopefully with no electrical damage done...just your nerves.
:::
:::In your taking of the reading that I specified using a bit of loading, lets us know that reading is not an insignificant miniscule level of static voltage.
:::
:::Will mull over the readings last given ... re do the work sheet ...and come back with testing info.
:::
:::For now....
:::73's de Edd
:::
:::This was a dupe, from just above, as I see that I was off from being at the very bottom of the string.
:::
:::--------------------------------------------------------------B/T---------------------------------------------------------------------------
::Wel l l l...after now seeing your newly supplied new M-a-g-i-c-a-l numbers... I only wish that you would have used that variac to bring up the AC line voltage slowly and have that +135 voltage at the very top of your string...being set to that value...but as you can see now, if you take the voltages that you supplied, they are equally spaced out at the proper levels, telling us that your Zener string is intact and all functioning to spec as required. PLUS your initial readings of the 24 Volt level told me that the D14 is intact and working properly. Soooooo you better shop around and find your self a new Qeeeew Teeeeeew (Q2).
::I think that original Roto-mola developed unit is reading out as a MPSA42 on that fuzzy schematic. Do you have ANY transistor stock...and as mentioned..... it is a higher voltage rated NPN silicon BUT being in a punier T0-92 case..along with lower power specs. If my unit, I would opt for a heftier TO-5 or to_39 configured replacement unit with its higher power specs....will research that '42-43 ? a bit more...as I probably have a bettter replacement in my 2k's plus stock level of xstrs.
::
::73's de Edd
::
:::--------------------------------------------------------------B/T---------------------------------------------------------------------------
:
:Worksheet withthe new #'s:
:
:http://img339.imageshack.us/img339/2402/newworksheetcd5.jpg
:
:After checking the specs for the '42 its working at about 1/2 its specified specs in this circuitry...so...I believe that I may have ~20+ of them ...but not here to check on, and confirm.... so I will confirm tonight...and be able to send you a pair with one for a backup... or if I have yet a heftier substitute / upgrade, I will send that also.
:On checking your "Job" name at the top of this page , I see that it is not "URL hot", sooo, on the next reply place include your E-mail addee also, just below your name in the box, so that I can then get a mailing addee from you to send the parts to.
:
:73's de Edd
:
:::--------------------------------------------------------------B/T---------------------------------------------------------------------------
:
::::Job
::::
:::: Believe Q2 is leaky or shorted emitter to collector. Check with an ohm meter.
::::
:::: Tranistor number isn't critical but needs to be NPN and high voltage rating. Can't quite read the original number but MPSA42 is rated 300 volts CE.
::::
::::Norm
::::
:::::I lifted the collector wire on Q2 as suggested by Norm and this is the results I receive now. All readings are from using B minus as ground....correct me if I'm doing this wrong.
:::::
:::::Q1..E-175v; Q1..B-177v; Q1..C-181v
:::::
:::::Q2..E-0v; Q2..B-73v; Q2..C-177v
:::::
:::::B+22..72v; B+45..94v; B+67..115v; B+90..137v; B+135..180v
:::::
:::::I'm not sure what this all means but maybe someone can interrupt it.
:::::Thanks
:::::
:::::Job
:::::
:::::
:::::
:::::
:::::
:::::::Job: If you're absolutely sure that the zener polarities are installed correctly, I'm suspecting the voltage regulator, Q1. Double check that it's installed correctly. (By the way, you can't really check a diode with an ohmmeter. Does your multimeter have a diode check function?)
:::::::
:::::::Here is a troubleshooting suggestion: temporarily jumper between C and E of Q1, and see if the B voltages come up to where they belong. If they do, you might want to consider the mods described in my website. That does away with the regulators altogether, resulting in a simpler circuit that works fine.
:::::::Doug
::::::Hey, Doug, I checked your website concerning your mods,and I agree with you that the Zeners are pretty much Voltage regulators in themselves, so why connect a Voltage regulator to a Voltage regulator? Besides, the radios should be designed to work well as the batteries run down, so why would you need a super carefully regulated Voltage anyway?
::::::
::::::Lewis L
OK with your ....E to C of Q2 reads 39 ohms...that says it all, so I will pull and mail you "whats"
you needs...au gratis.
As per the string, voltage being off at the bottom
portion, thats because you have the regulation capabilities disabled, with Q2 not even being in the picture now, but the zeners on up the higher voltage node lines were doing their job.
I see by the supplied semi referencing, that with Rota-molas transition to ON semi , the variant of the initial semi designator...but having the coincident Pwr,Vcbo, HFE, CI ratings, and all still being in the same plastic packaging configuration.
That Q2 unit, being utilized quite conservatively in this application, with max consideration being given to the units PIV spec ....with some cushioning provided to that max ~181 VDC presented.
73's de Edd
--------------------------------------------------------------B/T---------------------------------------------------------------------------
:I looked at a better scan of the schematic. Q2 is listed as an MPSW42 (1-W, high-volage NPN transistor). Here is the datasheet: http://www.ortodoxism.ro/datasheets/on_semiconductor/MPSW42-D.PDF
: