Scored an Admiral 19A11

[Crist Rigott]

OK, here's what I measured. There was no signal to the antenna terminals.

Also the "mains" was only at 114VAC. Hence the low voltage on the heaters and B+ was only 237V. When the mains was brought up to house voltage of 124VAC, the heaters went up to 6vac and B+ went to 257V.

[jr_tech]

Got to get some plate voltage to pin 2 of the 6J6 for openers...perhaps the 15 k resistor in A4 is open?

jr

[Crist Rigott]

Originally Posted by jr_tech

Got to get some plate voltage to pin 2 of the 6J6 for openers...perhaps the 15 k resistor in A4 is open?

jr

Yeah, I agree. I checked that resistor. It ohmed out to 21K. I'll pull A4 and replace that resistor too.

I went through the tuner last night in great detail. No problems found except that resistor.
I have another tuner and I'll clip lead the tuner in and try it then swap tuners and try it again.
Then go on to an alignment.

[jr_tech]

If it has only increased to 21K, I doubt that the voltage would drop that much (75 to 8.2 volts)... is the 6J6 ok?

jr

[Crist Rigott]

Originally Posted by jr_tech

If it has only increased to 21K, I doubt that the voltage would drop that much (75 to 8.2 volts)... is the 6J6 ok?

jr

Yeah, I agree. I'll swap out the 6J6 next time.

[Crist Rigott]

I pulled A4 1st IF transformer off the tuner to replaced the 15K resistor. It consists of the 15K resistor, a coil, and 2 mica caps at 10pf and 130pf.

Here is what it looks like:



I was expecting some "real" mica caps. Now I'm concerned that those caps could develop silver mica disease. I'm having some real trouble getting a cap reading on each of those with my cap checker. I could cut them in half and install real mica caps.

What do you think?

[jr_tech]

Is the 10 pf leaky to ground? that could pull down the plate supply to the 6J6. Otherwise, I think that I would leave them alone, and try to figure out the reason the 6J6 plate voltage is so low first.

jr