Dynacord S900 Limit chB problem

[madboy79]

Hello
After turning on the power - all red LEDs go out, but only Channel B Limit remains on
Channel A plays without any problems, but channel B is limited and does not have much power.

I noticed that when it works even without a load at the output - the radiator heats up

Input shorted. Output no load.
Output voltage in channel A, dc 0.66 mV to 0.90 mV / ac = 0 mV
Output voltage in channel B, dc changes quite quickly between 0 mV to 1.3 mV / ac changes between 3 mV to 4.2 mV

[madboy79]

After a lot of searching on the Internet - reading and watching videos, I repaired the amplifier. The problem was a defect in the operational amplifier (i302d) pin 13 I measured the voltage +10 volts / relative to the case / pin 14 also had +10 volts.
After replacing this opamp - the protection is not activated and the problem is gone. It remains only to check the BIAS current. The output voltage is 0.8 millivolts DC

[Jazz P Bass]

Nice fix!
Thanks for the update.