Have JBL MPA 400 amplifier. One channel is perfectly functional. The second channel not working.
The problem is in the protection modules.
I have the pdf schematic but the U 501, 502, 503 (for left channel) and U 601, 602, and 603 (for right channel) module unit not shown.
Only block schematics for this units. All this units very small and full of SMD devices. MPA series use this units.
Any help for repair the amp ?MPA400 Schematics.pdf