Re: Behringer DDM4000

Well, here we are, another case of crappy capacitors!

I replaced all 12 electrolytics on the SMPS board with mostly Panasonics, and a few Samwha. Re-assembled the mixer and it boots perfectly every time, all previous faults appear to have cleared!

At some stage I will get round to doing the processor board and main mixer PCB, but for now the mixer is working like new. Before it would fail to boot half the time, and when it did some features would be non functioning and weird symptoms like no bass on the outputs

Re: Behringer DDM4000

One comical point on this board. The 2 voltage regulators run very hot, so much so they are clamped to the metal box the board is in. 2 x 1000uf 85 degree capacitors are mounted right next to them, potentially to ensure after a few years use the mixer craps out and someone buys another!

Re: Behringer DDM4000

Id prefer to find the fault before I end up replacing every single capacitor. While that might be prudent for longevity, if the fault is not found to be capacitor related I will have wasted a lot of time on this.

The small caps I referred to were on the main mixer board, not a part of the SMPS. If I can get it booting properly and see some improvement from the PSU work, sure I'll go ahead and do every one I can find.

Finding them all in spec was disappointing and suggested to me they're not the problem. Someone has suggested to me...

Re: Behringer DDM4000

Unfortunately I pulled and tested each and every one of the 12 capacitors on the PSU board, EVERY single one tested absolutely fine and very close to their values. Now I didnt test them for leakage current, but I've found if modern electrolytic caps are bad you will see it in the capacitance reading.

No bulging underneath or leaking electrolyte. Starting to think this isn't going to be as simple as bad caps

There are many smaller 10uf or 1uf capacitors on the other boards, but as with these they are least visually fine.

Re: Behringer DDM4000

I don't want to risk damaging the windings on the isolation or flyback transformer by applying too much heat, but its a fair point, sometimes bad capacitors behave better when warm..

Its only 12 DECONs on the board, shouldn't take me long to swap them out. I'll replace with whatever I have at home and test everything I pull out. Hopefully something will show low capacitance or a bulge at the bottom

If this doesn't get me anywhere I'll have to assess whether this is worth continuing with. Its one thing to replace some caps, but if these...

Got this DJ mixer very cheaply, has various faults. After power has been off a while, switching on lights ALL the LEDs and it wont boot. At this point, switch off then on and again and it will often (not always) boot, or at least boot partially.

When its running it mostly works, though sometimes the EQs don't. I found the sound also quite lacking in bass with all EQs at zero.

Inside there are no obviously bulging caps, but the switchmode PSU unit has quite a few "DECON" caps, which I understand are rubbish.

Thinking to replace these and see if...

Re: New Members - please post your introductions here

Hi,

From London UK, looking for some advice on a Behringer mixer full of Decon caps!

Cheers