42-1003 code 122 bol - Printable Version
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42-1003 code 122 bol - sam - 09-05-2022
Hey guys
Working on 42-1003 code122
Has 8 tubes
In center is card board tube I think it’s suppose to be 40 electrolytes on both pins ? Schematic is ver bad to read I think looks like 5 electrolytes all together did recap went from low hum to loud hum light did work on chassis now not
Thanks sam
RE: 42-1003 code 122 bol - Radioroslyn - 09-06-2022
Hi Sam
I got six. #72 47mf@160v X2
#11 6mf@ 160v
#60 10mf@35v
#12 10mf@50v
#81 10mf 160v
RE: 42-1003 code 122 bol - sam - 09-06-2022
Terry
Ok I see 6 I don’t see where #81 is
Can not find a good schematic for code 122
If I replaced all caps why still humming ?
RE: 42-1003 code 122 bol - Radioroslyn - 09-07-2022
I couldn't find 81 either. But it's listed on the parts list and it's outlined on the under the chassis diagram under the tuning cap.
As for the schematic you gotta work with what you can get. The used the one in the library. Sometimes the service bulletins are better but we don't have that one. Maybe Andy has it and it's yet to be added to are files.
>Why is it still humming? There's a whole lot of possibilities. The short answer is there's ac getting somewhere it's not suppose to be. How are the dc voltages? Across the filter caps and plate and screen grid voltage on the output tube?
OBTW ru going to grace us with ur presence @ the town of K?
RE: 42-1003 code 122 bol - Ron Ramirez - 09-07-2022
It's in the service info, page 3 (page 121), bottom right of the page - but it isn't made very clear.
https://philcoradio.com/library/download/service%20info/yearbooks/1942/split/Part39-Philco%201942%20RMS%20Year%20Book.pdf
Here's a close-up.
I attempted to clean this up, but the quality of the original is very poor.
RE: 42-1003 code 122 bol - sam - 09-08-2022
Hey Terry
I will come Saturday
RE: 42-1003 code 122 bol - Ron Ramirez - 09-09-2022
You're welcome?
RE: 42-1003 code 122 bol - Radioroslyn - 09-09-2022
Tnx Ron,
Not quite sure why they are using a 50L6 as a rectifier but it's academic at this point as Sam's set doesn't use it.
I tend to be myopic and just lookup diagram not all the changes.
RE: 42-1003 code 122 bol - sam - 09-09-2022
Ron
Big sorry and thank you
I seen yours and terrys response and just wanted him to know I was going to k town
I am now just sitting down to look at darn radio
And mine has 3 50L6 ‘s and it has the 10 electrolytic which I replaced and replace the 2 40’s in can. 1 6 and 10 so I have to find the on that’s missing
Sam
RE: 42-1003 code 122 bol - Ron Ramirez - 09-09-2022
Yes, I too find it strange that Philco used a 50L6GT - an audio output tube - as a rectifier for the field coil. Very strange indeed.
RE: 42-1003 code 122 bol - MrFixr55 - 09-09-2022
This is definitely one of the weirder schematics that I have seen! I can understand using a 50L6 as a rectifier (I have seen that done with Emerson and RCA Lunchboxes with 37 triodes pressed into rectifier duty) but a 50L6 as a local oscillator for the 1st detector? There must have been a fire sale on 50L6s somewhere. I know that there was a war on (Production must have ceased shortly after the line was introduced), but i can think of better uses for 50L6s, like a push pull amp, voltage doubler rectifier (after all, the Phono makes this an AC Only set), etc.
2 things to look at. If your unit has the electrodynamic speaker (the reason for the 50L6 Rectifier), check the phasing of the field coil. I don't see a hum bucking coil in the schematic, but since there is only a 10 uF cap (81) filtering the output, phasing may be an issue. If you are missing C81, that's an issue too.
RE: 42-1003 code 122 bol - MrFixr55 - 09-09-2022
One other thing. Does it hum loud with the volume control all the way down? If so, then my diatribe above is the likely cause.
RE: 42-1003 code 122 bol - sam - 09-10-2022
Guys
With volume low it hmm low
The more you turn up louder hmm gets
I will bring to k town maybe Terry can look at it
Sam