Help with Scott A426
Hello,
I found a very nice looking Scott A426 but with not much life left in it.
When I first opened it this is what it looked like :
View attachment 612766
I started by checking all the transistors and all the output and bias ones were shorted. Also two resistors were blown and a diode shorted.
The transistors were Motorola references but in the service manual it had the 2sc/sa references for all of them. I replaced them as well as the other faulty components but no luck, still nothing. I started replacing all of the transistors on the rest of the power stage and the power resistors which were open on one channel. This is what the board looks like now (all the marked components are new)
View attachment 612768
but when I turn it on whit a lamp in series, this last one still lights up the whole living room and the output transistors get hot in about 5 seconds.
All the other components seem to be ok so I don't know where to look any more.
If anyone has a lead it would be very welcome.
Hello,
I found a very nice looking Scott A426 but with not much life left in it.
When I first opened it this is what it looked like :
View attachment 612766
I started by checking all the transistors and all the output and bias ones were shorted. Also two resistors were blown and a diode shorted.
The transistors were Motorola references but in the service manual it had the 2sc/sa references for all of them. I replaced them as well as the other faulty components but no luck, still nothing. I started replacing all of the transistors on the rest of the power stage and the power resistors which were open on one channel. This is what the board looks like now (all the marked components are new)
View attachment 612768
but when I turn it on whit a lamp in series, this last one still lights up the whole living room and the output transistors get hot in about 5 seconds.
All the other components seem to be ok so I don't know where to look any more.
If anyone has a lead it would be very welcome.
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