The dreaded DDX3216...

[liamstears]

So I've recently become the owner of one of these Behringer DDX3216 digital mixers, it was working fine but every now and again all the clip LED's would light indicating the power supply on its way out so decided to completely recap it. Recap went fine but then like an idiot I hooked it back up with the CTRL11 and CPU01 connectors swapped and since then I haven't been able to revive it

I know I blew the CPU and have swapped in a replacement complete CPU board. It did boot up once however after a period of time it locked up, most of the time though it will just sit on the splash screen and do nothing else (faders don't move/reset on bootup)

I also know 1 of the faders can be a bit dodgy but I can't see this stopping the desk from booting?

I have read about the crystal and have some on the way so will try swapping that out

What are my next logical steps? What is most likely at fault?

Even after the PSU recap it is very noisy like coil whine, I don't have test equipment so can't check ripple or anything but do have an option of having it sent off for a professional to check it over, should I explore this?

I have also read up about corruption on the EEPROM's, should I try swapping over the EEPROM's from my previously working CPU board before I fried it? Or would they have fried too?

Having 1 successful boot is making me personally think maybe its the crystal or power supply but I'm certainly no expert

I have a multimeter and happy to test as much as I can and give any info I can with relevant guidance

Really hope to get some advice as there are some very knowledgeable people on this board and I thank anyone that reply's in advance for any help they can give

[g1]

Are all voltages good on the PSU? If there was damage done from the connectors being hooked up wrong, it may have caused damage to the PSU as well.

[liamstears]

Are all voltages good on the PSU? If there was damage done from the connectors being hooked up wrong, it may have caused damage to the PSU as well.

From what I can tell yes, all voltages are present and close to actual voltage, 12v is a little low I think it was somewhere between 11.8-11.9v but I only have a basic multimeter

[g1]

Measure also AC voltages on the supplies. Should be around zero. AC voltage present will indicate ripple (poor filtering).

[liamstears]

So I've done some more testing and got some more information to add
Basically I bought a whole other mixer that supposedly only had a dead power supply which was missing/thrown away, this gave me my donor CPU board. Now I get to the hanging splash screen. I tried swapping the whole top section of the mixer with the one from the donor board and got the same result. I also tried switching DSP boards with the donor mixer and got the same result stuck on splash.

If I disconnect certain parts I do get errors on the screen like "fader calibration" errors if I disconnect the ribbon to the faders and "DSP not responding" errors if I disconnect the DSP so I think the CPU and CPU board are fine and going off of using 2 different mixer tops with the same result and the only common components being the output boards and power supply have I narrowed this down to a power supply fault? Or could there possibly be something on the outboard boards causing the mixer not to bootup?

I've replaced the crystal Q3 with a brand new one and its made no difference

I did do some AC testing, no AC on 3.3v 5v 17v -17v or 48v, I got 0.08v on the 12v line and 0.04v on the -12v line. I ran out of time so haven't checked the 8v rails so not sure what these power or how important they are?

Any more pointers would be much appreciated and I'll try to test the 8v tonight

[liamstears]

Measure also AC voltages on the supplies. Should be around zero. AC voltage present will indicate ripple (poor filtering).

Thanks for all your help so far