Behringer PMH1000 Europower Schematic Please

[devilock1138]

Can anyone PLEASE give me a schematic for a behringer pmh1000 europower. The company is useless. I would really appreciate it.

Thanks

[Enzo]

Behringer will not release schematics to anyone except authorized repair centers. The authorized repair centers have to sign a non-disclosure agreement stating they will not provide any technical documentation to others. So it seems unlikely.

However, we can answer questions as well as ask them. What is wrong with your mixer and what are you trying to fix on it?

[devilock1138]

The effects section is clipping & keeps resetting to program 1 every time you change the program it goes right back to 1. Its makes a clicking sound like a relay cutting out. There is also no output, on output A you get a reading of 24.5v reverse pol, output b you get reading of 1v. You can not power any speakers.

[Enzo]

And power amp output with DC on it is a blown amplifier channel.. Does that amp have a single two channel power amp or are there two separate power amp modules?

If it is ticking, I'd bet the power supply is resetting constantly. That might explain the FX unit defaulting constantly as well.


SO disconect all power from the bad channel if they are separate. If it is one stereo power amp, disconnect all ppower from it. There will be heavy wires for the main power but also a smaller wired connector for the low voltages. With power amps off connection, now power up the mixer. Does the mixer now work?

[sebasrodriguez]

Behringer pmh-1000: 1V DC on both PA outputs

I'm trying to fix the same mixer. It had a blown irf640 on one channel, I changed both mosfet(for the same channel), just in case, but couldn't change the diodes d5ld20u. They seem ok, although. After fixing the power amp, I found problems regarding the power supply... the -15V rail had -18 insted, so I changed the 7915 regulator and solved it. After all that work I powered the power amp section, with safety resistors in series with the power supply, and the current was aporx. 50mA on each rail. Evrything is fine until now, when I checked both outputs for DC I read 1.05V on both... but when I load them with 47ohms resistors I goes down to 20mV... That is OK. But I think that there should be (almost) no DC with the amp unloaded... any recomendations? It seems that nothing else blew.

[phil4christ57@gmail.com]

I may have mine. Will check tomrrow when I get back to shop

[Jazz P Bass]

20mv DC offset is nothing to worry about.
If everything else checks out o/k.

[lalunatech]

I get over a peak volt of 200kHz signal on both power amp outputs even after I replaced the faulty 1uF output filter cap and the burnt 1u4H inductor L3. It must be normal for these amps. 0.8 Volts RMS into 4 ohms is 160 milliwatts of heating in the speaker coil, nothing to worry about I suppose. One puzzling thing I did notice is that output A has the speaker polarity reversed. Speakon 1+ goes to ground, 1- has the signal?? I traced the red and black wires back to the amp and they are on the right connectors. Doesn't this mean the Left and Right are out of phase?

[Enzo]

It is a sneaky way to get the most from the power supply. Check the phasing of the input signal.

SInce most stereo signal will be pretty much similr side to side, if we run the power amps out of phase, the positive waveform peak on one channel will draw from the +V rail while the same peak on the other channel will draw from the -V rail. So the power supply caps only have to hold up for one channel at a time.

[lalunatech]

I see now, what a cheapskate way to go on. You're right, the input signal is antiphase on the A channel so the outputs end up in phase. I almost switched the connectors on the output board, glad I didn't. Better watch out not to connect a scope with a grounded screen to the -ve wire of the output, though maybe they have short cct detection. The PMH100 I had needed new output decoupling coils, new output filter caps 1uF (they measured at 700pF) and resoldering of two fader pots, wiggle them and they went full volume. With hindsight I should have told my customer to scrap it and buy different model. I had already fixed his PSU on an earlier visit. Oh Well!

[Enzo]

Cheap or efficient, it is all in your point of view. Think about the bunks for sailors on a submarine. They COULD provide a bunk for each sailor, or they could "hot bunk" two sailors per bunk, since sailors alternate 12 hour duty shifts two men never overlap. Takes up half the space.


If there is a way to do more with less, why not do it?

[lalunatech]

What if your bunkshare partner is a bedwetter?

[Enzo]

I guess that would piss you off.

[Martin Pedder]

Much web hunting a year ago did eventually result in me finding this. Am I going to upset anyone if I post the files here?

[Enzo]

Hi, welcome to the forum.

You can post any files you like, people would love to see schematics I cannot post myself. My agreement with the company has nothing to do with anyone else posting.