Amplifier output sound distorted

Thread Starter

Electrofoxtechnology

Joined Dec 23, 2018
7
Hello, i m new here ...i come to a stopping point when repairing a power amplifier.... I found and fixed every parts now its not shorted not in protective state....but the problem is ..output sound is distorte.. . Does anyone faced any problem like my?....how to fix this problem?




What i noticed was the transistor c5198,a1941 both of them get hot....after powering on....

Can anyone help plz
 

BBee

Joined Dec 6, 2018
35
You really need to check voltages around the circuit. As the amplifier and components are getting hot you should be able to find the problem. If it is stereo and one channel is Ok you should be able to compare. It may be sensible to limit the current flow to the faulty stage before it blows again. You ideally need a schematic to trace the circuit.

Tracy
 

Hymie

Joined Mar 30, 2018
836
It is almost impossible to diagnose a faulty circuit based on a photograph of the PCB.

To investigate the sound distortion, analysis the output signal on a scope would be very helpful.

But you might be surprised at the assistance you receive from others on this site.

Knowing whether the distortion is on one of both channels might assist with the fault diagnosis; but if all you have access to is a multimeter – effecting a repair might prove difficult.
 

Thread Starter

Electrofoxtechnology

Joined Dec 23, 2018
7
Thanks for the fast reply..i already checked all of the parts. And it on the left side...so i compared with the right side....all parts has been replace with good ones....thats why i asked the question...as i m at a dead end....i have no other idias to fix it....any help?
 

Hymie

Joined Mar 30, 2018
836
Although very much a guess, given that it is a class a/b amp, I would suspect that for some reason (a faulty driver transistor?) on the faulty channel, only the push or pull output is working (resulting in distortion). A scope would readily identify such a fault.
 

Ylli

Joined Nov 13, 2015
965
Pulled the service manual on the Yamaha XP1000/2500/3500. Quite a complex amplifier. Did you measure the output offsets and idle current?
 
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