01-03-2021, 08:56 AM
Anyone ever run into this one:
I've been doing a restore on a 48-482. Not completely finished with the recap, but extensive testing has revealed no more leaky caps (they WILL all be replaced, though.)
The AM and SW bands are pretty good and sound nice, even with a speaker with a 1 1/2" hole in it. The FM, however, sounds quite good at lower volumes, but breaks up and distorts as I turn it up.. sort of like a CRT blooming at higher brightness when there's not enough HV. This is usually caused by a bad coupling cap between the 1st audio and output tubes, but this has been replaced, and, as I said, the AM side does not do this. ss
It took me a lot of fidgeting to align the FM section, but finally got it to behave and it does have good gain and decent audio bandwidth. Any suggestions as to what I should look for?
Thanks, and Happy New Year.
I've been doing a restore on a 48-482. Not completely finished with the recap, but extensive testing has revealed no more leaky caps (they WILL all be replaced, though.)
The AM and SW bands are pretty good and sound nice, even with a speaker with a 1 1/2" hole in it. The FM, however, sounds quite good at lower volumes, but breaks up and distorts as I turn it up.. sort of like a CRT blooming at higher brightness when there's not enough HV. This is usually caused by a bad coupling cap between the 1st audio and output tubes, but this has been replaced, and, as I said, the AM side does not do this. ss
It took me a lot of fidgeting to align the FM section, but finally got it to behave and it does have good gain and decent audio bandwidth. Any suggestions as to what I should look for?
Thanks, and Happy New Year.
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