Hello all,
This radio worked when i got it, somewhat well, both am and fm. I started to recap the paper caps afew at a time and would retest the radio to make sure i did not make a mistake and it still worked. After the last few it did not work the same way, fm stations were far and few, only strong ones came in, am would only play on very low volume with me holding onto the antenna. Rechecked all cap values and locations, all is correct.
Started the Trouble Shooting from the schematic on NA.
Section 1: Power Supply, A=106 VDC, C=113 VDC, D= 124 VDC. Tested with a VoltOhmyst.
Section 2: Audio Circuits, Test points A,C,D loud clear output with strong and moderate input from the audio output of a IG-102 RF Signal Generator.
Section 3: I-F. Detector. and AVC Circuits, switched IG-102 to RF out set at 455 KHz with probe connection changed to RF out. B- connection in correct position and RF probe with .1 Mfd cap test point to 12AU7 pin 7. Pow, bang snap crackle snap snap snap crackle so loud i had to turn the volume down. tested the other points D and E much the same just less noise. Well, did i miss a cap placement or are the IF's gone after some new cap replacements?
Long post, alot of thought, but do look at the schematic and trouble shooting guide.
Thanks,
You folks that know me know i never post the easy ones.
Mitch

Silver mica migration problem got you again. There has been a rash of this lately.

:Silver mica migration problem got you again. There has been a rash of this lately.
:
Warren,
If my caps were correct and in the right locations they would not cause this issue? correct? There are four cans that i would be sending without cap values from the schematic, how would we know what to use for the caps. I have patience to work on the radios but am a very analytical engineer where absolutes are difinitives to me. I have never worked in a guess mode, in real life i have repaired equipment even without schematics as long as i could read the parts.
Help on your part as the expert.
Mitch

Certainly understand absolutes are definitive. In this case there is no definitive information. If an IF was found to be defective. It would only have been replaced by Philco part number, or the cross to replacement such as Miller coils. The silver mica caps can be measured by disconnecting one side of the coil. Use a capacitor analyzer to find the value. The other way is some guess work. Fine tune, add or subtract until you get the tuning slugs well within range. One possible way to find the worst leaky silver mica cap, is to measure from primary to secondary on the high ohm range of your meter. Disconnect the wires from the can pins first. Rebuild that one, align, go on from there.