Yamaha EMX5000 Powered Mixer - is disconnecting B+/- bad?

[tado921]

Hello all, I've been lurking for some time but this is my first post.

I have an EMX5000 mixer with a bad power amp. I think the SMPS is good, and I don't need the built in amp. I have removed the output transistors (A1492/C3856 pairs) and the drivers.

The B+/- is routed from the power supply to the amp board via a three wire connector, and I think the rest of the mixer will work without this connected. Can I simply disconnect this without any ill effects to the power supply or does it have to have a load to work properly?

At some point down the road I will take the time to fix it, but for now I just want to use the mixer without the amp. Any advice is appreciated, and I can provide a schematic if needed. Thanks!

Tad

[Enzo]

Usually you can do that. Try it. One negative possibility is that there may be some protection circuit that would miss those voltages and shut the system down. For examp-le in the Behringer powered mixers, you have to dissconnect the low voltage cable from the power amps as well as the +/-V cable for that reason.

[tado921]

Thanks, Enzo. I gave it a try and it works, but the power supply is making is making a strange buzzing noise. It sounds like its struggling to provide the voltages, which worries me. I've worked on this mixer before and don't remember hearing that noise.

I think it would be better to give it some kind of load to dump into. Any thoughts?

[Jazz P Bass]

One each of a 5K / 5 watt resistor on the B+ & B- rails, referenced to ground, will load the power supply pretty good.