[vecher]

All, Have unique problem with this set..

Here is a partial schematic..

[Image: https://live.staticflickr.com/65535/5085...2bea_c.jpg]

Capacitors C15 and C16 are in one can.. but it looks like I assume the Neg leads are in parallel with R12, R13 and the field coil. How is this even possible? The can is the Neg lead..

I will try to make a diagram of the way it is in radio.. but hard to trace ..

Really confused..

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[morzh]

No the negatives are indeed at the field coil and the 6X5G Cathode is the Positive.
I've seen many of these. They filter the negative.

Are you saying that the cans in your case are not connected to the field coil and the resistors?

[Radioroslyn]

When you restuff the can use two tabs on the bottom of the can for the negatives and a third for the plus. Or if there are two tabs run a wire out for the plus.

[vecher]

Ok wired up as schematic says.. AM now working great many stations.. but Short wave is not.. With volume all the way up all i get is a load hum.. however when i put signal generator on a piece of wire close by I can hear the signal ..

but when no signal all is just a hum no noise.. The closet schematic i could find is for a 6AO2 on radiomuseum.. matches my tube layout.. 6X5,6K6G,7B6,7A7,( 7H7 I have a 7L7) 7B8

What to check next?

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[vecher]

third wire is connected for SW antenna

Here is part of schematic I am using

[Image: https://live.staticflickr.com/65535/5089...680b_c.jpg]


Part 7 is band switch
Part 2 antenna coil
Part 3 Osc coil
M Short wave antenna padder
K short wave osc padder
F Broadcast osc
J Broadcast padder

Band switch in Broadcast position

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[mikethedruid]

Yes, in sets like this the 3rd wire is capacitively coupled to the other wires in the line cord, and allows the house wiring to serve as an antenna. This wire is NOT connected at the plug end ! It is NOT a ground. A similar set up was used as an FM antenna by Philco in the 48-482 and some other sets, where a wire from a plug into the FM antenna jack went to a metal tab which wrapped around the line cord and served as an FM antenna. This set up actually works pretty well in areas which have fairly strong FM signals.

[vecher]

OK hooked up a scope to the speaker here is what I get no signal volume low..

[Image: https://live.staticflickr.com/65535/5090...c3f6_c.jpg]

2nd picture

[Image: https://live.staticflickr.com/65535/5090...0d71_c.jpg]

its about 120 hz.. I did add some capacitance about 22 uf in parallel at C16... did not help at all..

I think if I can get rid of hum.. the AM and SW will work much better..

BUT have no clue on how to do it

HELP??

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[vecher]

OK went over this again.. I found that electrolytic C16 the minus lead was shorted to ground..

When ground was removed the hum went away,,

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