Hi All,
I have a Denon PM34 HiFi amplifier that presented with no output on the right channel.
On examination the main drive Darlington transistor pair was faulty together with a smaller NPN driving them.
I've obtained the matching transistors but have not soldered them in place and would like some advise before I do:
The faulty componants are:
Q762 2SD1894 Darlington NPN
Q764 2SB1254 Darlington PNP
Q752 2SC3419 NPN
My question is why did they blow in the first place and are there any componants I should check that may have led to their demise?
What I don't want to do is power up the amp with the replacement parts in place and instantly kill them.
Any thoughts would be most welcome.
I've attached the service manual and a picture of the amplifier board.
I have a Denon PM34 HiFi amplifier that presented with no output on the right channel.
On examination the main drive Darlington transistor pair was faulty together with a smaller NPN driving them.
I've obtained the matching transistors but have not soldered them in place and would like some advise before I do:
The faulty componants are:
Q762 2SD1894 Darlington NPN
Q764 2SB1254 Darlington PNP
Q752 2SC3419 NPN
My question is why did they blow in the first place and are there any componants I should check that may have led to their demise?
What I don't want to do is power up the amp with the replacement parts in place and instantly kill them.
Any thoughts would be most welcome.
I've attached the service manual and a picture of the amplifier board.
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