Behringer PMP3000

[Gtr_tech]

Got one of these in the other day.....warned the custy that I may or may not be able to do anything with it depending on the fault. The issue is in the SMPS....one of the 10r10w AC line series resistors was open (no sign of heat stress).
Just to check here....I show a short across the DC terminals of the bridge to the B+ supply (bridge tests ok when removed). I believe it hits a mosfet first thing and that may be normal for its "normally on" state. Sound OK before I smoke test this POS? I have no documentation on it so I'm working from instinct.

[Enzo]

JFETs are on until you turn them off, MOSFETs are off until instructed otherwise.

Those two resistors are a soft start. I show a pair of 22 ohm resistors, but they could have changed them to 10 easily enough. They are in series, and then in series with the mains. Relay K1 shorts across them after a second.

If you show a short across your bridge, then either your filters are shorted or both switching transistors are shorted. Check them - T3,T4. Says type 1MBK50D. That would sure crack those resistors for you.

A shorted load - a blown amp channel - can also crack those. Usually it shuts down the SPMS instantly, but it can damage the thing. SO check the amp. You can work on the SMPS unloaded and by itself, but you must disconnect not only the main three wire power connectors to the amp, but also the small 6-wire connector to the amp. it has a shut down signal on it that will turn on if the main powr is not right. DOn;t know why you'd want to, but you can leave the mixer connected or not.