This is an old amp a friend of mine has that I said I would have a look at. It won't come out of standby mode. Not much on it on the internet except a common problem listed as two resistors R 220 and R221 going out of tolerance causes this issue. Sure enough one is 50% out with 5% tol. and the other won't even measure. In the Sony service manual they are listed as part number 1-217-469-00 resistor fuse. Never heard of a soldered in resistor fuse before. Parts seem to be unavailable. I thought I had a line on them but they cancelled the order stating no source available. Long shot here but anybody know of a source on these or possible replacement? They are 1w 1ohm 5% Thanks, Lee
A 1 ohm resistor acts as a sort of fuse to prevent other (costly) damage. Not peeking at a circuit drawing right now, but blown fuses and 'fuseresistors' points to other problems, such as caps, endstage fails and what not. Thourough check recommended.
If you trace a Service Manual ('ServMan') and pm it, I'll have a look at the vulnerabilities
of the patient involved.
If you trace a Service Manual ('ServMan') and pm it, I'll have a look at the vulnerabilities
of the patient involved.
"fuseresistors' points to other problems". That's what I was thinking too. If they had just drifted a bit out of tol. I would have some faith that maybe just the resistors would fix it but the one fuse being open is not good at all. Thanks everyone for the input. I've been looking for similar fuseresistors without much luck so far. First time I've used diy for help and this is wonderful. I have some electronics background but not a lot. I did purchase a Whammy kit but haven't had the time to really get going on it.
A post I started here a few years ago about bias on a Sony TA-F444ES II eventually led to a rather extended discussion on fusibles and how they can drift (very significantly in some cases) over time, and as Goldie99 stated in the thread below, can choke off a Sony amp. illmzn and restorer-john were quite knowledgeable about fusibles as well, and the potential work arounds.
Is 70mv Bias correct for a Sony TA-F444ESII? - diyAudio
Is 70mv Bias correct for a Sony TA-F444ESII? - diyAudio
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