Hello Guys,
One of the guys I know in our hobby is having problems with his newly restored Philco 41-604 when he brings it up on full line voltage the set starts acting up but if he runs it on Dim bulb it works just fine .
https://philcoradio.com/library/download...20Book.pdf
Anyway Ideas .
Sincerely Richard
Define acting up? It looks like an AC/DC set judging by the diagram. I'm really just shooting in the dark here without having an idea of what is going on, but if all the capacitors have been replaced, correct values, correct voltage ratings, in the correct places, then it could be something like a gassy tube, or secondary emission from a grid. It also could be that a carbon comp resistor is failing, more voltage, more heat, and the connection inside is breaking down.
Regards
Arran
Hello Arran,
Yes He replaced all the capacitors !
Sincerely Richard
Rich
I will repeat Arrans request:
- Define "acting up".
Hello Arran and Morzh,
Here is what he wrote me " By act up, I mean it squeals and distorts between strong stations. Also, I have a strong station that shows up at multiple different frequencies."
he just ordered an NOS 7C6 tube because the original tube seems to have an intermittent issue.
Sincerely Richard
Quote:By act up, I mean it squeals and distorts between strong stations. Also, I have a strong station that shows up at multiple different frequencies."
I would look to miss connections, wrong cap/resistor values, shorts between terminals, solder blobs, wire snips, solder flowed between tube wafer contacts, poor riveted joints to chassis, even if the "best ohmmeter" says the joint is O.K. There could be corrosion issues with the coils, if resistance readings are higher, then there is a problem. The band switch must be cleaned with 91% alcohol and gently blown dry, use of "miracle" contact cleaners can result in leakage. Poor connections in the band switch could also be a possibility...
Re-wiring and not following the route of the original wires, especially in the RF/OSC and around the volume control, missing tube shield(s).
Overall, if the "shotgun method" was used to refurbish, that, in of itself, is responsible for the outcome.
It generally takes stage by stage analysis after eliminating a power supply issue if any to recover from cited issues.
Poking the chassis components with a tongue depressor, with set in operation, will often reveal oscillations occurring from juxtaposition.
GL
Chas
>>Poking the chassis components with a tongue depressor,
Chas,
Tongue depressors only depress tongues...and their owners.
hello Morzh,
Yes I had to to poke and press items on modern printed circuit boards to get sets to act up also the use of cold spray and heat .
Sincerely Richard
Quote:Tongue depressors only depress tongues...and their owners.
Many, many common "tools" can be "MacGyver'd" into service to serve another purpose. I also use the T.D. whittled a bit to apply wood filler in difficult places. One end sharpened to a point it becomes a marker in the flower bed...
To suggest the use of a pencil to poke a circuit has some risk, I could suggest a Delrin or Teflon rod but not many have a such laying about. A wooden dowel, fine, even the "Popsicle" stick, after consuming the quiescently frozen confection and drying the said stick.
Chas
I prefer a bamboo chopstick for poking around looking for issues. Usually get them with an order to go at our local Chinese restaurant. Kills two birds with one stone! Take care and BE HEALTHY! Gary
>>Kills two birds with one stone!
Exactly. First you use them to eat your Peking Duck, a bird #1.
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Then you tap on the chassis of that one.
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