DDA Q desk: Strange power issues

WarmJetGuitar

New member
We had our DDA Q for half a year now and love it's sound. However a serious issue has been occuring more than a few times. It's light will start blinking and if it doesn't get a break it won't pass any sound till it had a break.
I suspect either the PSU, the cable between the PSU and the desk or probably the sketchy power connection in our studio room.
Any ideas for troubleshooting? The PSU is placed somewhere with lots of ventilation possibilities so it shouldn't be that.

Regardless whats the reason for this would anyone of you know where I can get a spare PSU incl. cable? Is it compatible with other DDA desks?
 
Does the PS use a chassis fan? If so, is it working and clean or clogged with dust?

If not the case, is there more channels installed then what the PS is designed to drive? Are there provisions for additional PS units for larger frame consoles?

If that's all in order, I'd suspect voltage regulator transistors which are overheating or not properly thermal coupled to their heat sinks.

Is the PS hot to the touch when it goes into protect mode? Warm is probably normal. Hot enough to feel like you'll be burned if you don't quickly remove your had, is a different story.

About the imbilicle cable, does it appear damaged in any way? Cuts, loose connectors? If so, check for those issues with an ohm meter for shorts. If that's all good then look into getting the PS inspected by a trusted technician.

No idea about spares. Contact the manufacturer if they're still around.

Luck!



Cheers! :)
 
I have a Q II. The power supplies are known to be sketchy.
What light is blinking? There are power supply status indicators on the console (in the master section) and also on the front of the power supply.

I recapped my power supply and updated the regulators to more modern pieces. Its not that big a deal for a tech to tackle.

Replacement Power Supplies show up on ebay quite often but are expensive (900USD give ore take)

Is this the same as yours?

DDA "D" Series Power Supply Unit in Perfect Working Condition | eBay
 
Does the PS use a chassis fan? If so, is it working and clean or clogged with dust?

If not the case, is there more channels installed then what the PS is designed to drive? Are there provisions for additional PS units for larger frame consoles?

If that's all in order, I'd suspect voltage regulator transistors which are overheating or not properly thermal coupled to their heat sinks.

Is the PS hot to the touch when it goes into protect mode? Warm is probably normal. Hot enough to feel like you'll be burned if you don't quickly remove your had, is a different story.

About the imbilicle cable, does it appear damaged in any way? Cuts, loose connectors? If so, check for those issues with an ohm meter for shorts. If that's all good then look into getting the PS inspected by a trusted technician.

No idea about spares. Contact the manufacturer if they're still around.

Luck!

Sorry for not saying thank you and getting back to you in general, bit much travelling to do. Great advice mate. The PSU used to get seriously warm till we moved it. So far my tech friend have checked the cable between PSU and desk and appereantly it's all good though it had some crappy tapes attached to it from former repairs which have now been changed.
To my surprise the PSU doesn't have any fan... opened it and cleaned it, quite a bit of old dust piled up. Had a ten hour session recently where the desk behaved just fine but havn't yet given it enough hours to be perfectly sure it's sorted.

Cheers! :)

I have a Q II. The power supplies are known to be sketchy.
What light is blinking? There are power supply status indicators on the console (in the master section) and also on the front of the power supply.

I recapped my power supply and updated the regulators to more modern pieces. Its not that big a deal for a tech to tackle.

Replacement Power Supplies show up on ebay quite often but are expensive (900USD give ore take)

Is this the same as yours?

DDA "D" Series Power Supply Unit in Perfect Working Condition | eBay

That's some great advice :thumbs up:
Every LED on the entire desk is blinking when the problem is occuring. From then it goes quickly downhill if ignored. If given 20-30 mins. break it's usually fine but depends on something that goes way beyound my knowledge.
Ain't the same PSU as mine but might be compatible.
Whenever finances allows I'll ask a good tech I know to do a recap and change the regulators.
Might just be my head but it seems to my ears that the old beat is a bit more noisy after the latest breakdown. Slightly more hiss than normal when the tape ain't moving and the delay and reverb returns muted. Might be PSU related?
 
My unprofessional experience is any IC-based logic systems do really weird things when not getting the proper power (i.e. wrong voltage or "dirty" power like a DC rail with lots of AC components in it...bad rectifier or regulator)

Because it's happening when it's been on awhile and you think it's noisier than it used to be, AND because there's some correlation to "sketchy" power supplies even if on a different model, I'd be looking at the output of each power rail after its warm and, if possible, looking at them when connected to the console so there is some load. By "looking" I mean with an oscilloscope...looking for proper voltage but more importantly looking for AC infiltrating what should be clean DC power. You may not have the scope or the experience using it (maybe you do), and if you don't this is just some info to pass on to your tech of choice...and if he/she knows what he/she is doing, well he/she would probably know this already.

I suspect a recap is a good idea, and I suspect you have a dying regulator or rectifier...there may be excess heat exacerbating a solder joint that's gone bad from the extra heat and you are getting excess voltage drop causing the blinky...or forget the bad solder joint and maybe a part is dying and there is voltage division going on that shouldn't be happening. If the regulators aren't integrated and you have discrete transistors those can be pulled and tested with a transistor tester.
 
Sorry for being absent for so long, real life is quite busy these days.

Got the PSU back from repair a couple of months ago and it's running perfectly well. It's been recapped, got other regulators and a fan. The repair guy suspected that we'd been sold the PSU for the smaller 24 track version and he was really surprised why it didnt have any fan at all. It's been running perfectly well since and the fan ain't that noisy it bothers me.

Thanks for your invaluable guidiance :)
 
Back
Top