Mixer is dead apart from echo display flashing power supply pulsing

The flashing green light on your Behringer Pmp500 mixer desk indicates that it's receiving a signal, but it's unclear why the first 4 channels aren't working. Make sure that all cables and connections are properly secured and that the power supply is adequate for the mixer's needs. If the issue persists, you may need to consult a professional for further troubleshooting or repair.

Probably the power inside the mixer needs to be looked at.

If you registered your mixer there will be a three year warranty so get it back to your local Behringer service depot. If not check the output from the PSU, if that's OK then I'm afraid it is very unlikey to be economical to repair. Sell it as spares and repairs on eBay.

If you have the polarity correct for the connector, and adequate output from the transformer with adequate regulation and filterning, there should be little problem with constructing one or hacking the cord off the dead supply and wiring it to a new one.

The question you need to ask yourself is whether that wait is worth it? If you need it to make money with it right now- then just use care in wiring the new supply up. I have lost track to how many times I have rewired a supply to make it work on something it was not originally on. As long as the specs on the new supply match those of the old one- no problem..

Is the number on the effects display still flashing? Can you select effects or is that section dead now? I've had occasions with my Behringer mixers where a bad ground or otherwise improper power supply seems to cause issues with the effects section but the board seems otherwise functional. It has definitely had me scratching my head a few times and is worth investigating.

You will need to buy an effects unit for this, either delay or reverb depending on the echo you want, there are no built-in effects on this mixer, sorry!

Hope this helps!

View videos on YouTube regarding "mixer setup". Find the parts of setting up of "effects". Don't worry that you have a different mixer, the principles are all the same for analog mixers. Steps are this: Set the EFX send level for EACH of the input channels (knob above each channel gain) for the proportion you want for each channel. Check that the level you are sending does NOT cause the effect clip light to light very much. Set the effect you want, delay, echo, etc. with the selector knob. Advance the output sent to the power amp with the two knobs in the upper right of the panel. Adjust the "time" knob for the delay or effect depth you want. Then go over the same settings in the same order until you get the sound you want.

You should find +/-15 volts and +5 volts as well as the phantom power... but that light can come on at much lower than desired voltage.

Note that the regulators are current limited so a short on the mixer board can kill one of the voltages.... but you are not getting any input from teh switching portion of the regulator so the switching part of the supply is apparently dead. To replace the supply you would have to call Behringer at 1-425-672-0816 to get the part number and an incident number and then call FullCompass which is their part distributor now.

When working on a switching power supply, use an isolation transformer for safety and use a 60 watt lamp in series with the power cord to limit current during testing.

The circuitry will be SIMILAR to the power supply found on page 9 of schematic you can download at:

http://elektrotanya.com/behringer_ub1204fx_pro.pdf/download.html

Likely a power supply problem. Will require service. If uses external pwoer cube, try a replacement of correct rating and polarity.