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Admiral 10A1 more success
7/12/2001 10:04:10 PMRich in Ks
Last time I posted I mentioned I had a static problem. Well I found it. A 500 mmfd mica capacitor from pin 6 of the audio tube, a 6SQ7 to ground. The voltage on pin six was about 1/2 what it should have been and I could see the voltmeter jump slightly with each noise. I have replaced it temporarily with a .0022 mfd Polypropylene metal film capacitor (600v). Could this do any damage? The three shortwave bands work pretty good, better than the AM which only gets about 5 stations. Trying to get a signal generator now for alignment. Second question. Can I do a fair job with the signal generator for input and my lisening for the output or do I need an oscilloscope to do a good job aligning? Whats the most economical way to get a feel for what I'd be doing? Is there a DB meter etc that could be put accross the output? thanks, ... Rich
7/12/2001 11:47:17 PMNorm Leal
Hi Rich

A good find. The only thing a .0022 will do is limit high frequency response. No damage to your radio.

When aligning your radio measure the AVC voltage with a sensitive meter. More negative, the better aligned. You don't need a oscilloscope and this method is better than an output meter.

The AVC voltage usually starts with a 1 meg or greater resistor off the volume control. There will be a .05 mfd cap from the other end of this resistor to ground. Measure at this point. From here AVC should be going into the first IF Transformer and then grid of IF Tube.

Norm


: Last time I posted I mentioned I had a static problem. Well I found it. A 500 mmfd mica capacitor from pin 6 of the audio tube, a 6SQ7 to ground. The voltage on pin six was about 1/2 what it should have been and I could see the voltmeter jump slightly with each noise. I have replaced it temporarily with a .0022 mfd Polypropylene metal film capacitor (600v). Could this do any damage? The three shortwave bands work pretty good, better than the AM which only gets about 5 stations. Trying to get a signal generator now for alignment. Second question. Can I do a fair job with the signal generator for input and my lisening for the output or do I need an oscilloscope to do a good job aligning? Whats the most economical way to get a feel for what I'd be doing? Is there a DB meter etc that could be put accross the output? thanks, ... Rich

7/13/2001 10:26:39 AMRich in Ks
Thanks Norm, I will check it out.
Ruch


: Hi Rich

: A good find. The only thing a .0022 will do is limit high frequency response. No damage to your radio.

: When aligning your radio measure the AVC voltage with a sensitive meter. More negative, the better aligned. You don't need a oscilloscope and this method is better than an output meter.

: The AVC voltage usually starts with a 1 meg or greater resistor off the volume control. There will be a .05 mfd cap from the other end of this resistor to ground. Measure at this point. From here AVC should be going into the first IF Transformer and then grid of IF Tube.

: Norm



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