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Old 06-25-2014, 10:15 AM
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DavGoodlin DavGoodlin is offline
Motorola Minion
 
Join Date: Aug 2011
Location: near Strasburg PA
Posts: 3,400
Philco FM detector trans help needed

I have this 1962 Philco Stereophonic console HiFi that would play for about 10 minutes on FM until the static associated with silver mica disease begins.

After isolating stage by grounding grids of the two preceding stages, then confirming with some chopstick acupuncture at the suspect transformer's base, I carefully removed and disassembled it. The Sams schematic shows the three capacitors (without the values) within the transformer's base.
I have a document which shows typical values of these caps for Zenith radios and chose new cap values as listed on a similar configuration, which was obviously a discriminator transformer. (2@68pf and 1 @24 pf)

I drilled out the brass rivet, surgically removed the silver plated mica sheets and tabs from the base of my transformer and soldered it back onto the PC board. Then I added the new caps right onto the PC board. Now the AM and FM do not work at all. Turning the slugs MINIMALLY to re-tune the transformer to resonate at 10.7 Mc would be necessary but does nothing to change the issue. The continuity tests as it did before this operation.

Question: is there a resource where I can find the value of these caps specific to this transformer. I do not have a J W Miller catalog, which typically had a listing of catalog numbers for the OEM crossed to the replacement unit AND the characteristics of that replacement. Philco # is 32-4714-3, Miller; 1464-PC, Stancor RTC9050, Workman T658
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Last edited by DavGoodlin; 06-25-2014 at 10:11 PM. Reason: new part numbers
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