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Missing Cap on 118 - Printable Version

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Missing Cap on 118 - joejoe - 12-08-2011

I’m rewiring a Philco 118 highboy, due to damage to the wiring, using Philco service bulletin #194.
I am now rebuilding by-pass capacitor part 46 and am missing a 1mfd. capacitor. Part 46 has four (4) electrolytic caps in it, three (3) one mfd and one (1) two mfd.
I found three (3) caps and am missing one (1) cap, a one mfd cap.
Could the missing cap be mislabeled? Could the cap labeled 28, on the schematic, actually be part of 46?
28, on the schematic, is labeled 1 mfd; however, on the parts list it is listed as a compensating cap.
( I will try an attach a schematic, with the parts highlighted. )


Re: Missing Cap on 118 - joejoe - 12-08-2011

hopefully this link to the schematic will work. You may have to download it, I'm not sure. Sorry for the problem.


http://www.go2convert.com/converted/file/PX5HaamM


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Re: Missing Cap on 118 - Glenn Roberts - 12-09-2011

Joejoe,

Are you trying to locate them on the schematic? Because all 4 caps are in the same can.

Glenn


Re: Missing Cap on 118 - joejoe - 12-09-2011

Glenn, I believe that I figured this out late last night.

My schematic shows 46, by-pass condenser connections, on the lower left corner; however, if you search the schematic you will only find 3 caps labeled 46, when in fact there should be four capacitors labeled 46,on the schematic. One section, a 1 mfd section, is not labeled, or as in this case mislabeled, on the schematic.

I think that the schematic is wrong. The capacitor labeled 28 on the schematic is actually one part of 46 and is incorrectly labeled 28.

The capacitor labeled 29, on the schematic, is compensating cap 28 and the unlabeled 3000 mmfd, connected to the band switch, is p/n 29.

So far this is the third error that I found on this schematic and I really haven't started wiring the chassis.

Thanks Glenn.


FYI the other two errors on the schematic I'm using ( Philco service bulletin #194 ) are as follows:

1. On driver, tube 42, the plate and screen grid ( pins 2 and 3) are connected together, on the chassis but this does not show up on the schematic.

2. The screen grids (pins 3), of the RF and IF amps, tubes 78, are floating and not connected to the grid supply, composed of p/n 67, 68 and of course capacitor 46.