problem with my 999

I think problem solved...at least one. You stated you used 2sc2904 - an NPN, on the 1277 board. This board requires a PNP transistor for instance a ksa1220. The F-1231 (plus filter board) requires an NPN. Please check and confirm.

What is still a little strange is that the boards are not dedicated left side, right side - each plus/minus board serves both sides. So I'd expect the misplaced NPN tranny on the 1277 would cause trouble on the the left side as well :crazy:
 
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I think problem solved...at least one. You stated you used 2sc2904 - an NPN, on the 1277 board. This board requires a PNP transistor for instance a ksa1220. The F-1231 (plus filter board) requires an NPN. Please check and confirm.

What is still a little strange is that the boards are not dedicated left side, right side - each plus/minus board serves both sides. So I'd expect the misplaced NPN tranny on the 1277 would cause trouble on the the left side as well :crazy:

That is correct Tom, but it wont cause the rail fuse to blow, those transistors are used for ripple smoothing, they cause issues when the amp tries to run full power with early onset of clipping on the particular part of the sine that it is in relation to...
I am going to sift through those pictures and see if I can see anything.....
 
I didn't work on the left side yet, I don't want to be confused I had a ksa1220 there before, I will try again tomorrow, I have some visitor now
thanks everyone for the help so far
 
I try the light with removing the output same thing. and yes its the r847 that start burning

Remove the drivers and check the same thing.

Check the TR817 which should be a PNP 2SA566, this is on the negative rail supply. You may have the wrong transistor in there or it could be blown.

Go back and check TR813 and check the orientation and condition of that transistor.

Do not worry about that F1277 board yet, as long as it has a KSA1220 it will be fine....

There is something sorting out in the negative side of the driver circuit, and we need to find it.
Does the same resistor burn up on the other driver board?
 
I didn't work on the left side yet, I don't want to be confused I had a ksa1220 there before, I will try again tomorrow, I have some visitor now
thanks everyone for the help so far

Yes we are doing one thing at a time, see my post above...
 
I check the tr817, was testing good but I replace it anyway, same thing with the tr813
I install the ksa1220

I sent some picture with voltage
 

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In the last picture ....734 it looks like those 2 back-to-back diodes are shorting out on the earth braid - could be a perspective effect, but I'd want to make SURE there was NO chance of them touching.
 
if i am looking at right they go to the input /subsonic filter . so wouldn't cause the present fault if shorted to ground
 
I remove the subsonic filter , lots of people said it give you a better sound
hey slimecity I have 2 au-999 one have them , the other don't, so I just remove it
 
I think problem solved...at least one. You stated you used 2sc2904 - an NPN, on the 1277 board. This board requires a PNP transistor for instance a ksa1220. The F-1231 (plus filter board) requires an NPN. Please check and confirm.

What is still a little strange is that the boards are not dedicated left side, right side - each plus/minus board serves both sides. So I'd expect the misplaced NPN tranny on the 1277 would cause trouble on the the left side as well :crazy:

That's because they are essentially a smoothing circuit for the +/- rails, the fact they are positioned where they are is just out of convenience..each board serves both channels.
So yes one board will affect both channels with a fault, however, as stated before, a wrong polarity transistor in either one of these boards will not cause the amp to blow rail fuses....
 
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