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Help on 48-482 FM
#8

Thanks so much for your response Terry. Today I went through the IF alignment by the book, using the load each step of the way. It was peaking prior to alignment at around 9.2. It is now peaking at 9.1. The local oscillator is running at about 9.15. I get stations somewhat distorted. I hook my counter/scope to the detector oscillator and without a signal in, it is steady and clean at 10.4. With a strong signal, I can see some "modulation" in the detector oscillator signal. The adjustable detector coupling coil seems happiest all the way out (perhaps because of the high frequency), but doesn't peak. My questions are:
1. With no signal in (off station) shouldn't the detector oscillator run at 9.1 and be adjustable in frequency by the trimmer cap? My cap has no change on the frequency of the oscillator.
2. The cap does not appear to be a standard multi-turn compression type of trimmer. Mine seems to turn hard but doesn't have stops. Is this normal?
I'm beginning to believe that the oscillator is my problem and perhaps the trimmer is at fault. Should I be looking for another detector transformer or trimmer? Even if the slug in the coupling coil is broken or the coil is misaligned I would think I should still be able to adjust the oscillator section, am I wrong?
Yes, all caps have been replaced, talk about a bear. I was also careful about lead dress and location.
Your help is highly appreciated, I am new at this with no formal education in electronics.
Jerry

A friend in need is a pest!  Bill Slee ca 1970.


Messages In This Thread
Help on 48-482 FM - by jerryhawthorne - 11-12-2008, 03:57 PM
Re: Help on 48-482 FM - by codefox1 - 11-14-2008, 01:42 PM
Re: Help on 48-482 FM - by jerryhawthorne - 11-14-2008, 02:55 PM
Re: Help on 48-482 FM - by jerryhawthorne - 11-15-2008, 09:00 PM
Re: Help on 48-482 FM - by Ron Ramirez - 11-16-2008, 02:13 PM
Re: Help on 48-482 FM - by jerryhawthorne - 11-16-2008, 07:35 PM
Re: Help on 48-482 FM - by Terry Judkins - 11-16-2008, 10:01 PM
Re: Help on 48-482 FM - by jerryhawthorne - 11-17-2008, 07:01 PM
Re: Help on 48-482 FM - by Terry Judkins - 11-17-2008, 07:27 PM
Re: Help on 48-482 FM - by jerryhawthorne - 11-18-2008, 09:01 PM



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