MA3600VZ odd distortion on one channel
Posted 06 February 2013 - 12:17 PM
With no load attached:
With 4 ohm dummy load attached:
I happen to be using a 200Hz sine wave input, but some kind of distortion happens at all frequencies. The trace is shifted down, so the oscillation can be seen on the positive cycle.
Here are some more photos from today, with no load, at different frequencies:
Any ideas?? Note the huge negative spike at the same positive voltage level on every trace... Biases are all in spec and I've swapped everything socketed on the main board to no avail.
Posted 07 February 2013 - 07:05 AM
Posted 07 February 2013 - 08:25 AM
Posted 07 February 2013 - 08:43 AM
Posted 08 February 2013 - 02:00 PM
Apparently, it was a (or perhaps more!) output transistor! Since one the sides appear good, swap output transistors (6 at a time) and determine which set (if discovered!) was faulty. In my problem, the error side didn't generate any distortion. As far as your images demonstrates and if this solution is conclusive, could we have determined the fault with this information?