26-05-2020, 03:16 PM
Hopefully nothing too drastic then.
First step: visual inspection. Check fuses, look for overheated components, check for dry joints, etc, etc.
Next step: basic checks. Does it draw roughly the right current (power up using a lamp limiter)? Is the speaker output close to 0V DC?
After that, run a signal through both channels and follow it with your 'scope until you find the bit where the signal is no longer equally present on both channels. Then the fun begins!
BTW, some faults on audio power amplifiers can be extremely difficult. Hopefully this is not one such example. But don't be disheartened if it's not a quick fix, and do be prepared to do a bit of book-work with this - it will be a good learning experience. Luckily, the circuitry is very conventional, so knowledge and experience gained here will be useful in many other scenarios.
First step: visual inspection. Check fuses, look for overheated components, check for dry joints, etc, etc.
Next step: basic checks. Does it draw roughly the right current (power up using a lamp limiter)? Is the speaker output close to 0V DC?
After that, run a signal through both channels and follow it with your 'scope until you find the bit where the signal is no longer equally present on both channels. Then the fun begins!
BTW, some faults on audio power amplifiers can be extremely difficult. Hopefully this is not one such example. But don't be disheartened if it's not a quick fix, and do be prepared to do a bit of book-work with this - it will be a good learning experience. Luckily, the circuitry is very conventional, so knowledge and experience gained here will be useful in many other scenarios.
