03-02-2014, 08:08 PM
Not a good day today.
I installed the remaining electrolytics and replaced the AC line bypass cap, only to find that I had lost audio in the right channel.
What the heck? I checked and doublechecked wiring...nope, no wiring errors...no solder bridges. Output and driver transistors are OK...voltages at the output transistors seem to be OK...and going by the signal tracer, it even seems to have a clean signal all the way through the output coupling capacitor. But the output transistors became quite warm, and it appears two of those little 3 watt resistors connected to one of the output transistors were stressed by something as they just have that "stressed" look (darker than the other, similar resistors).
I should have quit while I was behind. But, oh no, I just had to attempt to clean that front panel using a procedure I had found at AudioKarma.
Something told me not to soak the panel, so I just used some warm water and detergent. I stopped when some of the lettering came off around the far right knob.
Then I attempted using polish, as suggested...and quit when I polished off the bird that was the Fisher logo.
Yup, there are some days when you should not attempt any work at all on electronics...
I installed the remaining electrolytics and replaced the AC line bypass cap, only to find that I had lost audio in the right channel.
What the heck? I checked and doublechecked wiring...nope, no wiring errors...no solder bridges. Output and driver transistors are OK...voltages at the output transistors seem to be OK...and going by the signal tracer, it even seems to have a clean signal all the way through the output coupling capacitor. But the output transistors became quite warm, and it appears two of those little 3 watt resistors connected to one of the output transistors were stressed by something as they just have that "stressed" look (darker than the other, similar resistors).
I should have quit while I was behind. But, oh no, I just had to attempt to clean that front panel using a procedure I had found at AudioKarma.
Something told me not to soak the panel, so I just used some warm water and detergent. I stopped when some of the lettering came off around the far right knob.
Then I attempted using polish, as suggested...and quit when I polished off the bird that was the Fisher logo.
Yup, there are some days when you should not attempt any work at all on electronics...
--
Ron Ramirez
Ferdinand IN