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-   -   Philco 112x electrolytics (http://www.videokarma.org/showthread.php?t=270314)

wdln 04-07-2018 04:06 PM

Philco 112x electrolytics
 
Hello all... I'm relatively new to this hobby but this isn't my first project.

I'm in the midst of rescuing a 1932 Philco 112x console radio. I've replaced the "easy" capacitors underneath the chassis and the unit does fire up and can tune in a station, but there's a lot of hum. I'm thinking the two big filter caps on the power supply are bad. They are listed as 6uF but the voltage is not specified. Should I just find something obscenely high to make sure it's covered, like 1000V, or is there a way to tell? I've tried putting a voltmeter across the terminals but it jumps all over the place on both AC and DC, which seems like further proof that they're bad.

Looks like there used to be a label on the outside of both of these but it's long gone. They are tall and encased in metal. Nostalgia Air has a fair amount of information and schematics but no capacitor voltages are listed.

Advice, anyone?

Titan1a 04-07-2018 05:32 PM

I recommend using 600V caps in the power supply. It's too bad you didn't replace those filter caps FIRST. I just got a 1936 116X that's being refurbished.

wdln 04-07-2018 06:03 PM

OK... I'm having some trouble sourcing 6uF's @600V. The electrolytics rated at 600V tend to be a much higher capacitance value. Additionally, 6uF seems to be a non-standard value. Would 8uF @450V work? Or 10uF @500V? If it doesn't have to be an electrolytic, there are many more options, but the schematic does call for an electrolytic. I'm a bit out of my element here but I want to learn.

I hear ya on replacing them first, but the P.O. (and who knows who else) had already plugged it in and messed with it, so whatever damage was done was already done.

The 116x looks cool... it gets some of the non-broadcast bands. My RCA K60 gets some of that too. Most of it is silent except for the "International Band".

dieseljeep 04-07-2018 07:55 PM

Quote:

Originally Posted by wdln (Post 3197945)
OK... I'm having some trouble sourcing 6uF's @600V. The electrolytics rated at 600V tend to be a much higher capacitance value. Additionally, 6uF seems to be a non-standard value. Would 8uF @450V work? Or 10uF @500V? If it doesn't have to be an electrolytic, there are many more options, but the schematic does call for an electrolytic. I'm a bit out of my element here but I want to learn.

I hear ya on replacing them first, but the P.O. (and who knows who else) had already plugged it in and messed with it, so whatever damage was done was already done.

The 116x looks cool... it gets some of the non-broadcast bands. My RCA K60 gets some of that too. Most of it is silent except for the "International Band".

10 mfd@ 500 volts would fine. You could get away with 450 WV caps, but 500 volt caps gives that extra margin.
I don't think the B+ is that high, but 500s are a little better. :thmbsp:

wdln 04-07-2018 08:49 PM

Thanks @dieseljeep!


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