Pioneer SA-1040 Amplifier : RESISTOR (R592 - .33X2/5W) Making Smoke and getting super HOT !

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smarthawk

Joined Apr 24, 2020
29
So i just changed the fuse 3.15 amp to my amp and since then the front lights are very dimmed (seems like low in voltage) and the big white resister (R-592 (right channel, please see the attachments, there are 2 big white colored resistors for each channel) is getting super hot and i can see some white smoke coming from the resistor and had to turn off within 1 or 2 seconds before it blows up or cause other damage. it's not even clicking (the speaker protection relay), is there is something wrong with some component ? what seems to be the problem ? Some expert help please.
 

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MrChips

Joined Oct 2, 2009
21,126
If R592 gets hot then Q526 or Q532 would be hot as well.
Test for shorting across Q526 collector and emitter. Do the same for Q532.
 

Ylli

Joined Nov 13, 2015
949
If R592 is getting hot, then you should have blown the fuse again. Either you put in a fuse with a much higher rating than the 3.15A you mentioned or the resistance of R592 has gone high.

In any case, you almost certainly lost at least one of the output transistors in that channel. Many times a failure in an output transistor ripples back into the drivers, so my suggestion is to remove and test:
Q602, Q604, Q614, Q616, Q522, Q524, Q526, Q528, Q530, Q532
If you don't know how to test a transistor with a DMM on the 'Diode' range, google it (or send the amplifier out to a professional).
Also, check the resistance of R592 - both sections, R586, R588, R590.
 
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