I know this isn't a common amp to work on, but I am grasping at straws for a heads up on doing a latch test on the left channel on my amp. Typical story where it was working fine the last time it was played, then go to put it back in the system and the left channel is shooting sparks off the speaker wires when tying to connect them.
The only service manual I can find is for the 9220A amp, which according to the schematic has a different board layout than the 9220 does. The first thing in the service manual is a latch test when the amp develops over +/- 3V. This amp has a THERMOEFFICIENT mode switch that when is not activated, makes the amp just go in and out of protection mode. The amp will power up if you activate the switch. I'm getting -15V to -6.3V DC voltage out of the left channel, the right channel still works , offset voltage is around 50mV in the right channel.
From what I am reading in the service manual, the latch test will bring it out of latch up when it's done properly. Is there anyone in here that has had any time working on AB amps with this problem?
I can't post pics of the schematic, so I'll link to the service manual for the 9220A that shows the latch test. Compare that PCB to my PCB. I'm lost.
https://www.hifiengine.com/manual_library/ab-international/9220.shtml
The only service manual I can find is for the 9220A amp, which according to the schematic has a different board layout than the 9220 does. The first thing in the service manual is a latch test when the amp develops over +/- 3V. This amp has a THERMOEFFICIENT mode switch that when is not activated, makes the amp just go in and out of protection mode. The amp will power up if you activate the switch. I'm getting -15V to -6.3V DC voltage out of the left channel, the right channel still works , offset voltage is around 50mV in the right channel.
From what I am reading in the service manual, the latch test will bring it out of latch up when it's done properly. Is there anyone in here that has had any time working on AB amps with this problem?
I can't post pics of the schematic, so I'll link to the service manual for the 9220A that shows the latch test. Compare that PCB to my PCB. I'm lost.
https://www.hifiengine.com/manual_library/ab-international/9220.shtml
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