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Can Cap Questions for 50-922
#1

Hello!

I have started the restoration process of a Philco 50-922 and I have some questions about the can capacitor.

First of all, I need help determining which capacitors to use when re-stuffing this component. My can cap is wrapped in an orange cardboard tube with the following information printed on it:

MALLORY
TCT3118
MFD VDC
80 150 RED
50 150 BLUE
50 150 ORANGE

NEG BLK
MADE IN U.S.A.

The schematic and replacement parts list both have C14A (RED), C14B (BLUE), and C14C (ORANGE) listed as electrolytic capacitors with values of 30 MFD, 40 MFD, and 40 MFD respectively.

There is obviously a discrepancy here. Is the can cap an original part or a replacement? Since nearly everything else on the radio seems to say "Philco" on it somewhere, it makes me wonder. If it isn't an original part, then it's pretty clear that I need to re-stuff this can with capacitors as specified on the schematic/replacement parts list. But if it IS an original part, which values should I buy to re-stuff the can?

Secondly, I'm trying to figure out how to open up this can to gut it and re-stuff it. I've not opened one up before, so I'm not sure what I'm going to find inside the shiny aluminum shell. The top has an epoxy/resin surrounding the three colored wires. Is the entire can typically full of this resin or is it just in the opening? I've searched a bit and can't seem to find a good procedure for cleaning it out.

Finally, can I just forego the can completely, build an assembly with the three new caps, insulate the leads with heat shrink tubing, and put them inside the cardboard shell, leaving the aluminum can out completely? Or does the can serve some sort of purpose?

Thanks for any help you can give! It's been a couple of decades since I've worked with tube electronics, and I'm excited to get going on a hands-on project again.

--
DeShawn Smith
Current Project: Philco 50-922
#2

Lots of threads here and on Antiques Radio Forum about various ways to dissect cans, if you wish to restuff. almost all methods involve sawing the cap apart at the bottom and pulling or melting out the innerds. Of course you can mount a terminal strip and use modern discrete electrolytics, (and I would use reputable brand fresh stock 450 volt ones regardless,) and stick close to the schematic values for best results. Of course do not leave old can connected to circuit.
#3

Hi Deshawn

I would use values close to the original, as Codefox mentioned. However, be aware that 30 uF (MFD), 150 WVDC and 40 uF, 150 WVDC are generally not standard values these days.

They may be safely replaced with 33 uF, 160 WVDC and 47 uF, 160 WVDC, respectively.

I would skip the aluminum can and hide the new capacitors inside the original cardboard shell. Be sure you insulate the lead wires really well so that they cannot touch one another!

--
Ron Ramirez
Ferdinand IN
#4

Thanks to both of you for the information.

I think I'm just going to ditch the can and put the new caps in the paper tube. And yes, there will be plenty of heat shrink tubing used for electrical isolation.

I'm hoping to put together a replacement parts order sometime today.

--
DeShawn Smith
Current Project: Philco 50-922




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