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Philco 42PT--No Power
6/24/2007 4:10:48 PMJob Goudie
First let me thank everyone who has so graciously helped me in the past with radio repairs. Also Edd, I still haven't installed that diode in the power supply I was having trouble with but once summer is over I'll be getting back to my fantastic hobby.
Now for the problem with this Philco which a friend dropped off assuming that I was supposed to know what I was doing with those tube radios..lol..Anyhow, there is no voltage whatsoever except where it enters the chassis at the switch and filament resistor and across those two points I am reading 118v...There is absolutely no voltage getting to the filaments, anodes, etc. of any the tubes. The electrolytic capacitors are replaced and there is continuity between all points that I could think about checking. Also, the tubes all checked out o.k but I did replace the 35z3 just in case something was wrong with it. I'm assuming that there is probably a ground but I'll be darned if I know where.....I will more than welcome any suggestions to get this radio working.
Regards

Job

6/24/2007 4:38:47 PMDoug Criner
I see several 42-PT-xx models. Can you link us to the correct one?

But is it like this one? http://www.nostalgiaair.org/PagesByModel/567/M0013567.pdf

If so, attach you voltmeter where you are getting 120V. Then work your way around with one lead on the filamemt string, and find where the voltage is zero.
Doug


:First let me thank everyone who has so graciously helped me in the past with radio repairs. Also Edd, I still haven't installed that diode in the power supply I was having trouble with but once summer is over I'll be getting back to my fantastic hobby.
:Now for the problem with this Philco which a friend dropped off assuming that I was supposed to know what I was doing with those tube radios..lol..Anyhow, there is no voltage whatsoever except where it enters the chassis at the switch and filament resistor and across those two points I am reading 118v...There is absolutely no voltage getting to the filaments, anodes, etc. of any the tubes. The electrolytic capacitors are replaced and there is continuity between all points that I could think about checking. Also, the tubes all checked out o.k but I did replace the 35z3 just in case something was wrong with it. I'm assuming that there is probably a ground but I'll be darned if I know where.....I will more than welcome any suggestions to get this radio working.
:Regards
:
:Job

6/24/2007 5:02:12 PMJob
Doug---The fullmodel number is Philco 42-PT-7. I followed your instructions and received full voltage on all of the tube filaments...no zero voltage
Job


:I see several 42-PT-xx models. Can you link us to the correct one?
:
:But is it like this one? http://www.nostalgiaair.org/PagesByModel/567/M0013567.pdf
:
:If so, attach you voltmeter where you are getting 120V. Then work your way around with one lead on the filamemt string, and find where the voltage is zero.
:Doug
:
:
::First let me thank everyone who has so graciously helped me in the past with radio repairs. Also Edd, I still haven't installed that diode in the power supply I was having trouble with but once summer is over I'll be getting back to my fantastic hobby.
::Now for the problem with this Philco which a friend dropped off assuming that I was supposed to know what I was doing with those tube radios..lol..Anyhow, there is no voltage whatsoever except where it enters the chassis at the switch and filament resistor and across those two points I am reading 118v...There is absolutely no voltage getting to the filaments, anodes, etc. of any the tubes. The electrolytic capacitors are replaced and there is continuity between all points that I could think about checking. Also, the tubes all checked out o.k but I did replace the 35z3 just in case something was wrong with it. I'm assuming that there is probably a ground but I'll be darned if I know where.....I will more than welcome any suggestions to get this radio working.
::Regards
::
::Job

6/24/2007 6:13:55 PMDoug Criner
OK, Job, here's your schmatic: http://www.nostalgiaair.org/PagesByModel/568/M0013568.pdf

Let's try something else.

(For info, when the tubes don't light on an AC/DC radio, 98 times out of a hundred, it's a burned out tube filament. 1 time of a hundred, it's the power switch. This is all just my hunch.)

So do this. Unplug the radio, and turn the power switch on. Measure the resistance across the two power plug prongs - probably around 300 ohms might be normal.

Now check the resistance across the power switch - should be less than 1 ohm.

Now check the reistance across each tube's filament at their socket. The resistance will vary between tubes of different voltage ratings, but should be a few tens of ohms.

Then check the resistance across the two dropping resistors, 40- and 80-ohm each.

Please report back your results.
Doug

:Doug---The fullmodel number is Philco 42-PT-7. I followed your instructions and received full voltage on all of the tube filaments...no zero voltage
:Job
:
:
::I see several 42-PT-xx models. Can you link us to the correct one?
::
::But is it like this one? http://www.nostalgiaair.org/PagesByModel/567/M0013567.pdf
::
::If so, attach you voltmeter where you are getting 120V. Then work your way around with one lead on the filamemt string, and find where the voltage is zero.
::Doug
::
::
:::First let me thank everyone who has so graciously helped me in the past with radio repairs. Also Edd, I still haven't installed that diode in the power supply I was having trouble with but once summer is over I'll be getting back to my fantastic hobby.
:::Now for the problem with this Philco which a friend dropped off assuming that I was supposed to know what I was doing with those tube radios..lol..Anyhow, there is no voltage whatsoever except where it enters the chassis at the switch and filament resistor and across those two points I am reading 118v...There is absolutely no voltage getting to the filaments, anodes, etc. of any the tubes. The electrolytic capacitors are replaced and there is continuity between all points that I could think about checking. Also, the tubes all checked out o.k but I did replace the 35z3 just in case something was wrong with it. I'm assuming that there is probably a ground but I'll be darned if I know where.....I will more than welcome any suggestions to get this radio working.
:::Regards
:::
:::Job

6/24/2007 8:55:11 PMJob

Doug-----Your hunch re "one time out of a hundred" it's the power switch is correct. I have already replaced the switch and the radio plays beautifully. Thanks for making me look good to my friend.....I'm kidding.
I'm sure I'll be in touch again.
Regards

Job

:OK, Job, here's your schmatic: http://www.nostalgiaair.org/PagesByModel/568/M0013568.pdf
:
:Let's try something else.
:
:(For info, when the tubes don't light on an AC/DC radio, 98 times out of a hundred, it's a burned out tube filament. 1 time of a hundred, it's the power switch. This is all just my hunch.)
:
:So do this. Unplug the radio, and turn the power switch on. Measure the resistance across the two power plug prongs - probably around 300 ohms might be normal.
:
:Now check the resistance across the power switch - should be less than 1 ohm.
:
:Now check the reistance across each tube's filament at their socket. The resistance will vary between tubes of different voltage ratings, but should be a few tens of ohms.
:
:Then check the resistance across the two dropping resistors, 40- and 80-ohm each.
:
:Please report back your results.
:Doug
:
:
::Doug---The fullmodel number is Philco 42-PT-7. I followed your instructions and received full voltage on all of the tube filaments...no zero voltage
::Job
::
::
:::I see several 42-PT-xx models. Can you link us to the correct one?
:::
:::But is it like this one? http://www.nostalgiaair.org/PagesByModel/567/M0013567.pdf
:::
:::If so, attach you voltmeter where you are getting 120V. Then work your way around with one lead on the filamemt string, and find where the voltage is zero.
:::Doug
:::
:::
::::First let me thank everyone who has so graciously helped me in the past with radio repairs. Also Edd, I still haven't installed that diode in the power supply I was having trouble with but once summer is over I'll be getting back to my fantastic hobby.
::::Now for the problem with this Philco which a friend dropped off assuming that I was supposed to know what I was doing with those tube radios..lol..Anyhow, there is no voltage whatsoever except where it enters the chassis at the switch and filament resistor and across those two points I am reading 118v...There is absolutely no voltage getting to the filaments, anodes, etc. of any the tubes. The electrolytic capacitors are replaced and there is continuity between all points that I could think about checking. Also, the tubes all checked out o.k but I did replace the 35z3 just in case something was wrong with it. I'm assuming that there is probably a ground but I'll be darned if I know where.....I will more than welcome any suggestions to get this radio working.
::::Regards
::::
::::Job



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