Basic M1A damaged TA2040 module

Buffi

New Member
Hi all
I'm going to try to fix my "new" M1A power amplifier and I would like to share with you all my experience.
The amplifier does not switch the output relay and the red light on the panel blinks continously.
After some investigation, I found the High Voltage output power NPN device shorted inside the TA2040 power module.
I want to play with this unit, so I will try to bypass the shorted NPN with an exeternal one.
The question is: if I "simply" isolate the shorted bjt, the unit can work with "low level" signals.
If I understood well, the TA2030 module makes a switch between Hi voltage and Lo voltage power device output driver, and the decision is made by reading the output voltage level. So, if the output voltage level is low enought, the Hi voltage output device will never be turned on...
Is this correct, or all of 4 output devices are always pre-polarized?
I will post photo of the unit and my work later.
Thank you in advance to any with a concrete idea of how the TA2030 module really works in practice.
 
Bad news.
I removed the damaged TA2040, the companion TA2030 and replaced "super-dld" capacitors in the power supply stage (2200uF/35V from part list) and... I got 9V of offset from the remaining channel.
I think this amplifier will be dismantled definitively....
 
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