marantz 140 peak light stays on

[quadmatrix82]

Hi all, I just acquired a lovely Marantz 140 power amplifier and it works perfectly but the right channel peak meter light stays on all the time, has anyone encountered this before? can anyone shed any light why this may happen and if its an easy fix? thanks!

 

[SB Marantz]

It could be a defect in the corresponding channel or the relais/protection circuit.

 

[quadmatrix82]

thanks for that, i've looked for dry joints etc but all seems ok. Also, if you overload the left channel to get the peak light to come on, the right channel peak light turns off - very strange!

 

[jblmar]

Could also be a shorted component in the Peak circuit.
You need to determine that the amp is working properly or the Peak circuit is the problem.

 

[quadmatrix82]

hello, the amp is working fine, both channels are clean and noise free. the light stays on all the time which is bizarre, i'll check the protection circuit board unless anyone has any other suggestions? thanks!

 

[SB Marantz]

I have had a 170DC with the same problem.
It turned out to be a bad 2sc-945.

 

[glen65]

Hi all, I just acquired a lovely Marantz 140 power amplifier and it works perfectly but the right channel peak meter light stays on all the time, has anyone encountered this before? can anyone shed any light why this may happen and if its an easy fix? thanks!

Check the components on the meter drive board.
The transistor designations should start with HX.

 

[jblmar]

I'll bet you have a shorted transistor on the Peak Indicator board.
Instead of the transistor(s) switching on when the signal exceeds a pre set voltage then 'off' when the voltage levels off, they're always 'on' and the Peak light remains on.

 

[quadmatrix82]

thanks for everyone's responses, i am going to find to have another look shortly and report an update!