Did you see the Pioneer troubleshooting guide posted on Audiokarma today? It should be very useful.
Craig
Craig
Back again after some time away, yes Craig I found the guide and will definitely refer to it for the bias problem.
Something different, I have another SA-8800 which had a full recap and was working more than fine but these days when I power it up there is a very loud noise on one channel (sometimes over 10W on the display). It disappears after a few minutes.
I had the same problem on a Luxman L31 and this turned out to be a leaky transistor.
Are there any transistors in these SA 8800 that are known to fail ?
Something different, I have another SA-8800 which had a full recap and was working more than fine but these days when I power it up there is a very loud noise on one channel (sometimes over 10W on the display). It disappears after a few minutes.
I had the same problem on a Luxman L31 and this turned out to be a leaky transistor.
Are there any transistors in these SA 8800 that are known to fail ?
Concerning the noise I had on one channel, cleaning the relay did the trick.
I've been doing some research, reading the troubleshooting guide Craig was talking about and came to the conclusion that lowering R101 and 103 should get the bias down. I put a 1k resistor in parallel with those and the bias did come down about 10 mV. Than again I don't know if this could potentially alter the working of the rest of the circuitry. Would you say that getting 80mV between the two test points, (that is between emitters of Q1 and Q5 or Q2 and Q6 for the left channel) instead of 70mV is too much or just leave it at that ? The amp does run a little hotter than normally but sounds actually better that the one with a setting at 70mV.
I've been doing some research, reading the troubleshooting guide Craig was talking about and came to the conclusion that lowering R101 and 103 should get the bias down. I put a 1k resistor in parallel with those and the bias did come down about 10 mV. Than again I don't know if this could potentially alter the working of the rest of the circuitry. Would you say that getting 80mV between the two test points, (that is between emitters of Q1 and Q5 or Q2 and Q6 for the left channel) instead of 70mV is too much or just leave it at that ? The amp does run a little hotter than normally but sounds actually better that the one with a setting at 70mV.
Since the tech working on it was clearly clueless, he probably also put in fake new outputs. I mean, how did he even have those parts in stock? Obsolete since forever and one of the most faked parts of all time. Have that checked out, too.
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