It's been a long time....ge a52 question

[stusnyder]

Hi all,
Been a long time since I was last here. Alot has happened. Moved, took a year to get the house livable. Work, ect. Last November had a brain tumor removed, got lung cancer. Wife said sell off some radio's to help pay medical bills.
Enough about me, I'm working on a nice GE a52. everything is ok till the speaker gets hooked up. At that time, according to the diagram, I believe resistor r10 (1000k) burns up. Any clues as to where to look?
Thanks in advance,
Stu

[old_coot88]

Originally Posted by stusnyder

...resistor r10 (1000k) burns up. Any clues as to where to look?

Well, R10 is 1K ohms, and carries B+ to the primary of 1st IF transfomer (and plate of the 6A8). There's bypass cap C24 (.1 mf) which if shorted would cook R10.

Look for short-to-ground at the junction of R10, C24, and 1st IF xfmr primary.

[stusnyder]

Hi old coot88, how have you been?
that did the trick. Does not burn up anymore. Went ahead and replaced all the papers. The 6q7 was dead so replaced it. All tubes test good. Ecaps replaced.
Now when I get to a station setting all I get is hum and buzzing.
Where to look now?

[old_coot88]

When you tune to a station, you can hear the audio but it's overriden with hum/buzz. Is that correct? If so, it sounds like 'tunable hum'. It's probably due to 'floating grid' condition of the 6A8.

Check for continuity from grid (top cap) of the 6A8 to the junction of R2 (1 meg), C8 (.05mf).

From this junction (the AVC bus), there should be solid continuity back thru the RF coil and bandswitch to 6A8 grid. Any open along this path would cause 'floating grid'.

[stusnyder]

I checked and got continuity. What it does is it is quiet until you approach a spot. sounds like it locks on to something. No voice or anything just buzzing and cracking noise and hum.
Also, is 0.1 mfd and .1 mfd the same?

[old_coot88]

Man that is a stumper. Any chance you could post a UTube of what it's doing?

Yes, 0.1 and .1 are the same. Not sure what purpose is served by putting a 'phantom zero' there. Maybe to call attention to the decimal point.

[stusnyder]

Now I get nothing out of it. No buzz, audio or noise. I do get a click thru the speaker turning the band switch.....but thats it. Tubes check out ok.