Behringer DDX3216 revival

[Wayne Leeds]

I have a (nearly) dead DDX3216. Please help me revive it. I am not an electrical engineer. But I have a scope, dmm, soldering station, and some experience repairing electronics.

The mixer has a recapped power supply and the 32.768MHz crystal has been changed.

(1) The (unloaded) power supply voltages seem okay -- but what are the specs? Since the 3.3V is adjusted whenever the 5V is adjusted, is there a priority? Or happy medium? There are other rail inter-dependencies as well. What about those?

(2) When powered up, the LCD has bars briefly, and then goes blank. A variety of switch LEDs come on, sometimes shifting during the boot. The faders shift a couple of times during boot. It seems to me that the CPU must be running since there are (messy) square waves on many of the AM29F040B flash memory chip pins -- although the OE pin, which I suspect should be twiddling, is steady state. Any suggestions on what to check for CPU board operation?

I'm getting another one of these (heaven help me) soon and should be able to compare signals, but, until then, can anyone help me diagnose this beast???

Thanks,
Wayne

[Mick Bailey]

I don't know that specific piece of kit, but in general with processor-controlled equipment the 3.3v needs to be as close as you can get it, as many processors will test for this during the boot sequence and if it's out will halt the process. Usually (but not in every case) the 5v supply has a little more tolerance. For example, the AM29F040B is spec'd at 5v +/- 10%. If you can't adjust the 3.3v and keep the 5v within tolerance then I'd take a look at the PSU again, as it would suggest a problem there.

I would check the voltages at their destination - directly on an IC pin, and monitor them during the power-on sequence.

Do any of the ICs have error lines? If they do and the CPU reads them this may shut the equipment down.

[cosmo3405]

Wayne,
Hello and cheers over your dilemma. Maybe I can offer some encouragement/insight. I have 3 of these mixers and have completely re-built all three. May I ask if your mixer was working prior to your re-capping of the power supply?

[S2udio]

Wayne,
May I ask if your mixer was working prior to your re-capping of the power supply?

Good question before we go any further ?
Sounds like a possible CPU board fault as the display is directly coupled to it.
With all ribbons disconnected from the CPU board the display should then Display DDX3216 , followed by bars and then blank.
Using a scope will get you nowhere , due to the complexity, you need a working example for that.

[EAR]

Does anyone have experience upgrading the DDX3216 V 1/1, from software that is on a MacPro Quad?
Any advice is greatly appreciated. Thank you. EAR.

[S2udio]

I think the file exchange software is only windoze.
I don't use macs so.......anyone else ?

[Wayne Leeds]

Re: Behringer DDX3216 revival

The mixer was not working fully before the power supply recap. I am currently trying to diagnose the CPU board in isolation. I have a working unit to compare to. On each of them, at the moment, I have only the power connections to the CPU board and the CNTRL11 board (for LCD backlighting), no digital connections, and ICs 3, 15, 16, 17, and 18 removed (only IC 19 installed). The good mixer shows "No valid program / Restart update" about one second after power-up. The bad mixer shows a blank screen. Any suggestions?

[Jazz P Bass]

A blank screen can be either a bad LCD or the LCD is not being 'initialized'.
Typical LCDs have power, ground, Read/Write & D 1-7 pins.
If you have the power & ground pins, then you need to look at the R/W & D pins with a scope.

[Wayne Leeds]

Thanks for your reply. The LCD subsystem is known-good -- works fine in a working mixer.

[Jazz P Bass]

Well what drives the LCD?
It appears to be the main micro, IC23A.

So unless you have any open 15 ohm resistors, shorted caps (LCD), open traces or bad solder joints........

[S2udio]

Dead CPU chip....someones probably pluged the Fader/Control board connector into the CPU board........not the first one seen !

Replace the AMD cpu.

Otherwise you are wasting your time ,IMHO

The Control board suffers as well !

Easy to verify with a working Swap CPU Board and a known working Desk .
Oh BTW as far as I can recall you need all the eproms present .
And A good OS IC19
If in doubt swap a good set into the suspect board.
All are easily copied with an EP programmer.
You should get various messages on screen when boards are missing.
Otherwise .....Dead brain.

[Wayne Leeds]

Thanks for your response S2udio. I suspected as much. I recall having seen a post from you about having that processor. Do you have any? Or do you know where I can get one or two?

[S2udio]

I think I have one spare will check and send you a PM