PMP3000 board replacement

[ltelford]

Hello all, I am wondering where I can get or if I can get the pcb to swap out for the SPS1000/01 in the Behringer mixer board.

We had and issue where the fuse blew out on the board and then someone replaced it with a regular fuse and I beleve what we have is the slow rise circuitry was affected. I opened the case to find that R12 was missing one side of the resitor, but no charring of any kind. The relay seems to ohm out fine, other than the fact that I did not apply power to it to cehck its function. There may be a problem with one of the Mosfets in that cicuit as it showed short and think that was an earlier indication of an issue in that same slow rise circuit.

With there being so many issues on this board I was wondering if I can just replace the board. I am an old navy guy so board swap is where it is at for me, and I have been given authorization to do this by my boss. However I can go to component level if this seems to be an issue.

Basically I need help and this seems like the place.

Thanks

[Enzo]

Behringer doesn't sell boards and they don;t release schematics. Those two resistors are shorted across by the relay after a pause. They blow apart when excess current flows through them. SO either the power supply itself is blown up, or the power amps have a blown side.

If your MOSFETs are shorted, then you have at least that much wrong.

[ltelford]

Thanks Enzo, here is what I have next now. I got a new power supply from Full Compass for the unit and have installed it correctly. When I go to power the unit up it makes the click noise but then does not turn on but rather starts to heat up and smell electrical. I shut it down and opened it back up and R12 and R11 are very hot.

I am perplexed now, as the symptoms have changed but I still have no power to the board. Thanks

Behringer doesn't sell boards and they don;t release schematics. Those two resistors are shorted across by the relay after a pause. They blow apart when excess current flows through them. SO either the power supply itself is blown up, or the power amps have a blown side.

If your MOSFETs are shorted, then you have at least that much wrong.

[Enzo]

You very probably have a blown up amplifier channel.

There are two heavy wired three-pin connectors from the supply to the power amp. Red, blue and I forget. Pull those off the connectors. At each connector on the ends of those wires, measure resistance from red to blue, and from each to the center (ground). If any show shorted, that channel is blown.

You can check the power supply. Pull those power connections off, and also there is a smaller wire - 6 pins I think - connector for low voltage over to the power amps. Disconnect that. Now power up the system. Check for voltage at the exposed male pins of the three-pin connectors on the power supply. Be aware, that if the supply charges up, those supplies will hold substantial charge for a long time - no bleeders. SO if you get the 80v or whatever, use a resistor to discharge them before going further.

You have to disconnect the low voltage connector because in the absense of main high voltage power, the amp will send a shut-down signal to the power supply.

[amptech]

pmp3000 mixer/power amp unit.

Had that same unit in last week with blown power amp board and part working psu.

After replaceing the 'soft start resistors next to the relay due to damage and more checking around the psu, as enzo said there's 85 volts feeding the power amp plus that smaller L T connector. I moded this unit using a power module by class D amps ltd that can work on 90volts plus adding some bleeder resistors to 'drain' the amps power caps.

From the main mixer unit there's a small signal plug connector that plugs in the main amp, just cut it and hard wire it to your replacement 'power amp' and your ready to go.

The best thing to do is, dont wast time trying to rework that power amp board if there's to much damage, instead unplug the amp feeds and add some bleeder resistor to the row of power amp supply caps. then you can use the unit as a mixer and send signal to a slave amp.

best of luck with that unit...

[zero cool]

yup, if the supply wont turn on...the amp is dead. I have been able to repair the amp modules successfully but not so much luck with that power supply. the IGBT transistors are expensive and seem to blow easily!

On the other hand. if anyone wants to send me there blown up Behringer amp modules or power supply boards. I will gladly pay for shipping

[Steve Conner]

Amptech, which modules did you use from Class-D Ltd?

As far as I know, they don't actually make Class-D amps. The name is just a marketing thing, and all of their amp modules are regular Class-AB with lateral MOSFETs, like the old Trace Elliot power amps.

So if the original modules were really Class-D, the cooling might not be adequate for the new ones.