Vintage Synth Repair

I just got a broken Memorymoog. It's really clean, near mint in fact, but not working. Half the reason I bought it is because I like a challenge :o) ..I haven't even opened it up yet so I thought I'd post up the problems to see if anyone has an idea.
 
It boots up ok, but makes very little sound the most you get out of it is a thump or slight squeak when you hit a key, the same pitch wherever you hit. The digital side seem to be mostly working.
 
If you hit autotune it comes back with '0 tuned' so it can't tune any of the oscillators probably because it cant 'hear' them so to speak.
 
First thoughts are some kind of DAC problem.
 
2: All the LED's on the left hand side don't work at all but the buttons do. A few are just stuck on all the time, again the buttons work.
 
3: one digit on the alpha/numeric display is barely visible.
 
4: this is a slightly weird one which is hard to describe, when you move the pots the numbers in the alpha display move up and down which is correct., however say you turn one pot and move to another, well the first pots status doesn't clear from the display, it's stuck there, you can see it flicker as you move the other pot but it's stuck there unless you go back and zero the original pot. Only a few pots seem to cause this problem.
 
Any ideas would be helpful. Obviously the first thing im going to check is the PSU when I open it up later.
 
Thanks, Phil.
 

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