I know exactly what you're talking about and am also fully aware of the potential for damaging a PCB with static electricity. I've repaired a number of other Korg, Roland and Oberheim keyboards however, this issue is a little strange and something new I've not seen before. I suspected the voltages and checked the output from the power supply and everything is right on the spec (+/- 5V and +/-12V) as listed on the PCB next to the wiring harness connector going to the voice board, processor board, etc. The funny thing is if I repeatedly switch on and off the power switch I can sometimes get the display to read correctly. Most of the time it just powers on with a string of characters in the display and pressing the keys simply enters new characters in the display as though I'm typing them in. Using another fully functional Matrix 6, I've replaced the processor board with the problematic board and receive the same issue so it's something faulty on the processor board itself. I haven't as of yet checked the voltages on each of the IC pins on the board. If the voltages look okay, then something possibly an IC or other component in the circuitry providing data to the display has gone bad and needs replacement. If I make any progress I'll repost again to pass on what I find. Thanks for the reply!

--- In oberheim@yahoogroups.com , Martin Ator <cyllall@...> wrote:
>
> I don't have a Matrix 6 so don't know exactly what's wrong. What happens, if this has a back-up battery for the memory, is they go flat, then someone who doesn't know what they're doing, goes inside to investigate the problem, then they destroy the memory chips with static electricity because we all wear plastic clothes these days. I fix my synths in my birthday suit to alleviate any risk of this happening(not good if the postman knocks at the door)
>
> Check the battery for correct voltage, check that any protection diodes are working near the battery. Check that the battery voltage (if present) is reaching the power pins of the memory chips.Look for any damage.Check the main power supply.
>
>
> And finally, if you don't understand anything I've said, then send your synth to a qualified professional to be repaired, or sell it. You will only make a great job of destroying a wonderful synth otherwise.Poking things with a screwdriver will not make them work again.
>
>
>
>
> ________________________________
> From: wesleyknick <wesknick@...>
> To: oberheim@yahoogroups.com
> Sent: Wednesday, 18 July 2012, 7:08
> Subject: [oberheim] Re: Oberheim Matrix 6, Dead
>
>
> Â  
> Any luck figuring a solution to your problem I have a Matrix 6 that does exactly the same thing. I see you post is over a year old but I thought I'd ask anyway.
>
> --- In oberheim@yahoogroups.com , "sloppyofficial" <sloppy.hq@> wrote:
> >
> > HELP!! im having problems with my oberheim matrix 6.
> >
> > when it came to me less than half of the presets worked, the rest were just noise. so i reloaded the sounds from the original audio tape and to my absolute joy/astonishment it fixed it 100%.
> > but now about 2 months later, I tried turning it on after not using it for about a week, and it wont even light up(at first). so i tried turning it off and on quickly. when i do that the display lights up and reads either "HHHHHHHHH","PWPPPPPPP","@@@@@@@@@" weird letter combinations like that(3 different combos consistently)i cant find if those are some kind of error code or not anywhere on the web.
> > Its been plugged into a very good power conditioner since i've had it, so im not betting on a power surge as the culprit. i know a little bit about circuits and electronics, nothing looks burnt out on the board, nothing smells burnt. i removed every IC i could, cleaned and reseated it, but still same thing as before(on/off slowly = nothing, on/off quickly = letter combos)
> > any way im just curious if any one has ever seen or heard of this before, and what it might possibly be, i couldn't find a single thing about it online!
> > i love this synth, it have become my favorite one in the past couple of months, i would hate to see it die.
> >
>