Behringer PMP960M power supply PSU18

[Mick Bailey]

I've got a mixer (UK mains 240v) to repair that the owner flipped from 240v to 120v while it was operating because he wasn't happy with the EQ.....

Anyhow, can anyone tell me what D30 and D31 are? - both have been vapourized. I guess there's more trouble down the line and a schematic would be nice, or if someone has one and can't release it could they have a quick scan to see what else may have blown.

[Jazz P Bass]

D30_D31 are 1.5KE200A transient suppressor diodes.
Cross to 1N603A

Why the heck did they blow on an undervoltage condition?

SMPSU18.pdf

[Enzo]

Not undervoltage. He has 240v mains, and they flipped the switch to 120v, so the SMPS was getting twice what it thought it should.

The 1.5KE200A should be readily available in the parts market, Mouser sells them for 57 cents.

[Jazz P Bass]

Ooops.

Yes, ahem. Twice the voltage.

I will not be surprised if there is not more damage.

[Mick Bailey]

Thanks guys.

With a lot of luck these may have clamped the voltage and crowbarred the fuse. But then again.....

[Jazz P Bass]

Oh, and when you finalize the repair, DISABLE that 120/240 switch.

[Enzo]

Amen.