A while ago I've bought an DS-2 at Ebay. When it arrived here nothing was working... :(
the former owner didn't mentioned it wasn't working...
but, thats ebay and it was quite cheap.
On the first look at the inner life I saw the first fault - The DS2 has some kind of 'slot in' card system, but you can't screw the cards in, like in a PC. And what happes if you don't use screws on the cards in your PC? Exactly, they get loose (especially when shipped with the 'good' service from the german mail.)
The same goes for the DS2 - the cards were not stuck propperly into their slots... so the first thing to do was to  reconnect all the cards in the DS2.

But my Crumar remained silent. no blinkenlights, no noise, nothing... :'-( *sniff*
So I checked the PSU but my DMM showed the normal +/- 12V and +5V...
I gave it to a friend to have a look at it, cause i was clueless.

He figured out it WAS the PSU, changed the regulators and it worked again!

After the PSU was working again, the big synth had to return to my home (strange looking  taxi driver included because I don't own a car) to have a coser look at it.

Now nearly everything worked again

Remaining bugs were:

- the synth always played the lower F

- the two envelopes were stuck in sustain phase

First I thought the envelope circuit was faulty (P440). But this wasn't the case. So I went over to check the gate Signal (thanks to SDIY mailinglist)

BINGO! No gate signal. So I checked the keyboard control.
Following the cable for the gate signal, I ended at the "Memorized Keyboard Code" PCB P431.

Cleaning of the IC's and sockets had no effect (very often it's a mechanical and not an electronic problem, so clean the contacts) ) so I just changed all the IC's on  P431 cause all are still available and in sockets, so they were easy to change.

And now, after this little IC change procedure, my DS2 is working fine.

LFO 1 is stuck sometimes :( and the polymode has a fault. sometimes it just goes silent. touching the poly mode pcb helps, but I didn't figuered out where the cold solder joint or whatever is.

But what was it ALF said?: "If I can't fix it, it isn't broken" ;)

If you need the schematics just drop me a mail