I could use some eyes on the issue I'm trying to sort with a QSC RMX-850 amp.
The owner told me that it continually shuts down. I followed the service manual recommendation of using a Variac to gradually increase the voltage from zero while monitoring the current draw. At 40VAC going in to the amp, it's drawing about 11.5A with no signal and with and without an 8 ohm load. I disconnected VCC+ and VCC- from both channels, but no difference. I then went over the power supply board, starting with the two bridge rectifiers. They measure as expected with a diode check, albeit in circuit. Everything else in the PS checks out ok. I'm stumped. And I feel like I'm missing something obvious. . . .
The owner told me that it continually shuts down. I followed the service manual recommendation of using a Variac to gradually increase the voltage from zero while monitoring the current draw. At 40VAC going in to the amp, it's drawing about 11.5A with no signal and with and without an 8 ohm load. I disconnected VCC+ and VCC- from both channels, but no difference. I then went over the power supply board, starting with the two bridge rectifiers. They measure as expected with a diode check, albeit in circuit. Everything else in the PS checks out ok. I'm stumped. And I feel like I'm missing something obvious. . . .
