Working on a Meyer Sound MSL-4 and a 700HP for a client. Both are experiencing faults where they start to power up, but as soon as the green "Acvtive" LED starts to illuminate, each unit powers down.
I have a copy of the service manual which says to measure DC current on the harness coming from the power supply that feeds the amp heatsink module. The voltages are spec'd at +/-15VDC, +/- 43VDC and +/-108VDC. The MP-2 (MSL-4 module) is metering at +/-15VDC, +/- 64VDC and +/-115VDC. The HP-2 (700HP module) is metering at +/-15VDC, +/- 50VDC and +/-115VDC.
The service manual specifies that the +/-43VDC and +/-108VDC outputs are unregulated and may vary from the "typical" value, but as long as the positive and negative rails are even, all should be well. With that bit of info, it appears that there is no issue here.
Past the above, the service manual does not provide any further instruction for diagnosing my issue. I contacted a colleague who installs a lot of Meyer and he contacted one of his factory contacts, who said at this point I should send the modules in for repair.
Before commiting to that expense, I'd love to hear from anyone who has had similar failures and hopefully what the resolution was.