DDX3216 repair

[obiwanjacobi]

Hi

My name is Marc and I am from Holland/the Netherlands and this is my first post after finding this awesome forum.
In the beginning of this year I picked up my old electronics hobby again and started buying stuff I could repair in order to sell it (as working) again (with a slight profit).

I have bought a non-working Behringer DDX3216 digital mixer and trying to get it to work again. I have already found several interesting threads here.

The one I got starts up with the full screen logo and then stops. The guy I bought it from said he replaced one of the Flash ROM ICs (IC15) with one from a working unit and that fixed the problem. In my ignorance I bought a new chip but after further examining the machine (having a schematic does help greatly) I concluded I may just have to rewrite the firmware. I have tried to connect over MIDI but the firmware load program (I got from the Behringer site) does not pickup the connected DDX3216.

There is also an RS232 port that can be used and my question is: will that work better (guaranteed)? Any tips on reflashing the firmware on one of these?
(problem is I don't have a rs232 cable but will get one if I know this has a chance of working ).

Thanx,
Marc

[paleeman]

Hi Marc.
If you have a firmware problem, you will not be able to upload it via midi. The mixer needs to be in a fully booted state to be able to receive data for firmware upgrading. You're only option is to use the RS232 and the program provided by Behringer for that purpose. Also, my suggestion is to read the threads on the forum about the DDX 3216, similar issues have been discussed before.

cheers

[obiwanjacobi]

Figured as much.
What I read in other threads did not cover the details of how to actually do the firmware update...

Does the RS232 require accurate timing and handshake?
I was thinking on buying an USB to RS232 cable but those may be not too fast and not sure if the complete RS232 protocol (handshake) will be implemented.
I still have one old PC with a RS232 on-board that will probably be a bit more accurate...

What would be best?

[paleeman]

It would definitely be easier with a computer that has RS232. (I use USB to RS232 on a laptop and have no speed issues) And you'll need the V1.11 update tool to be installed. It will ping the DDX on the RS port and begin to upload the SW. But before this, I'd explore a few options. Like, replacing the 32.768MHz crystal. It is a common fault with these units. And the symptoms are like the ones you described.

Just in case, DDX3216FileExchange11f.zip DDX3216 Presets.zip

[obiwanjacobi]

Thanx,

I have managed to get an RS232 cable - should be in the mail today or tomorrow.
I will try rewriting the firmware first seems the simplest option. I already had a poke with my scope on all the clocks and reset lines which all seemed ok - supply voltages also although the plus 5 and 12 were a little low but not outside spec I think.

Keep you posted.

[obiwanjacobi]

Odd enough on one WinXP machine, the file exchange program did not start (process was started but no UI). Luckily I had another old WinXP machine with an RS232 interface that did work. But the program cannot find the DDX3216. Checked the RS232 cable with my meter and all pins had continuity.

So I think I'll have a look at that crystal again...

Any other know problems that have the symptom I am seeing (startup logo on the display but dead otherwise)...?

[obiwanjacobi]

The power supply seems to make some noise (coil whine)...?

[S2udio]

PSU needs a recap ,and replace the crystal, you are wasting your time with a firmware update as its not booting properly.
As said read the other threads .
The RS232 needs a fully working boot os to detect the DDX

[obiwanjacobi]

Yes, I opened the PSU and I saw one cap slightly bulging, but the rest looked fine. I ordered an ESR meter to be able to determine what caps are bad. I know you guys say that you should replace them all, but I like to know
The voltages from the PSU were all there and no alarming ripples on the 5 and 3.3 rails either...

Because the guy I got the mixer from told me IC15 was bad (he replaced it with one from a working unit and that fixed the problem - according to him) I fear I may not ever get a stable running OS. Are the images available to program the chips on an external programmer?

I see no JTAG header either...?

[S2udio]

You need an external eeprom blower to program the bin files ,they are unavailable..... I have them somewhere !

IC19 Is the OS Epprom the others are for the presets,position stores,config,effects etc etc.

As stated Replace the watch crystal FIRST !! this is one of the main cause of stopping at boot !!!

Just repeatedly replacing empty roms will get you nowhere

[obiwanjacobi]

Yeah, I know you guys want me to replace that crystal - I am just not very good at blindly following orders over the internet
I like to understand why - and because mine is working...?

[paleeman]

When a solution to a known issue is suggested, it is not an order, it is common sense. But on the other hand, if you want to learn on your own expense, it is fine by me.

The booting is in 3 steps. In phase one the CPU loads the necessary data to awake the primary system. For this the CPU does not need the crystal (SYS CLOCK), it has its own,
that is why you can see a splash screen. It is generated by the CPU. In phase two the OS is loaded to bring the device to the state where it can communicate with the peripherals, and for this you need the watch crystal, to generate the system clock, and finally the presets are loaded. Now, just now, the mixer is fully functional. Yours is most likely stuck at phase one.

Good luck. (and I say this as friendly as possible)

[Jazz P Bass]

I will agree on the 'splash screen' being independent.

I have seen it on Korgs too.

[obiwanjacobi]

Ah thanx very much.

I do not mind spending a little more time in order to understand what is going on. I do this as a hobby and have no deadline or something.
I also am suspicious of advice on the internet, because too many are like recap all and put in a new this and that and that will fix it. It might (and then again might not) but I want to know what is the problem exactly.

Anyhow, I ordered the crystal, should be in at the beginning of next week. Meanwhile I will look into the caps of the PSU. I think someone already repaired it once, all power transistors have been resoldered (and the excess flux not removed).

About the splash screen: I have a broken tc-electronic Nova System that displays its splash screen - even now I have removed the processor! There is a little PIC on the display board that (probably) takes care of that. So I learned not to derive any conclusions on the state of the main CPU based on the appearance of a splash screen. In this case, the main CPU does drive the LCD so I see how your description is correct.

[obiwanjacobi]

I looked into recapping the PSU.
I can get 1500u instead of the 1000u caps that are used. Would that be a problem?
(I would think not but I'm no expert on switching power supplies)

Also I saw 50v caps for the 48v rails. Isn't that cutting it a little close? Would it not be better to up that a bit?