Digidesign Gear Repair

Siegfried Meier · Jul 7, 2015

Hey guys,

Has anyone ever fixed a 192 AD card, a MIDI IO or a PRE unit? One channel of the AD card is noisy, the MIDI seems to be giving weird lights and is not coming online for me, and the PRE is frozen upon startup, although it does show DL when you hold OSC+SHIFT upon boot up, indicating that the Boot Loader is ok with the unit.

I have essentially zero dollars in these items, but I'd love to repair what I can. Lots of SMT, and I really am not sure where to start with this stuff. Not much info or documentation online, people generally just send it all back to AVID for a hefty repair bill…I'd like to not do that…

Any help much appreciated!
Thanks,
Sig

Siegfried Meier · Jul 8, 2015

Ahhhhh no one is crazy enough to take these suckers on eh!

ruairioflaherty · Jul 8, 2015

The AD card should be reasonably easy given that you have 7 working channels to compare to. The 192 allows you to mount the cards in such a way that you can probe with the lid off.

I haven't looked closely at mine in forever but check what AD chip they are using and find the data sheet, the conditioning circuit before the AD chip will probably look similar.

I'm not sure I would make any effort with the Midi IO, too cheap used.

[silent:arts] · Jul 9, 2015

We have repaired a few SPSUS in PREs in the past.
I do have one PRE open, with the same error you are describing.
All voltages are fine on the Test points, haven't had any time looking further into it.

mrclunk · May 28, 2021

Did you ever get anywhere with these?
I have a dead one showing 888 on startup. (DL when you hold OSC and SHIFT buttons)

I suspect something is shorting the 5V rail as initially this is @ 5V on the test point but then a relay (or many, hard to tell) switches on and the 5V rail goes down to about 4.6V.
I have checked the coils on all the relays and they measure the same, 500 ohms approx.
The SMPS seems fine tho. Solid 5V out of it at all times.

I'll bring my scope in next week to dig deeper..

Apache5 · May 29, 2021

About the pre. In some PRE 8s that I have seen with the error you describe, it turned out to be a problem in the panel, where I think there is the uC. When avid was supporting this product you sent them the panel and they sent you back a different "new" one. Maybe it has to do with problems in the uC and there is no way to repair something like that in a simple way.