I would start with downloading service documentation:
Then PSU, maybe it needs recapping.
Then cleaning and reseating all connectors, IC's in sockets...
Keys need also cleaning, finding what's wrong with those not working,
and repair it.
Then calibration as described in the service manual.
Maybe this way you can find where's problem, and change failed
On 7 Dec, 2013, at 8:13 AM, <
> Hi everybody!
> I have obtained a OBXA 120 patches model recently. It was in full
> working condition ( I saw the demonstration by Skype). But after it
> finally came to me I ´ve noticed some problems:
> 1. Two keys are stiffer and are not working
> 2. Entire memory is wiped out - there is only noise with some
> modulation (battery shows 3V and is not leaking, manual mode works.)
> 3. I can ´t write any patch to the memory - instead of writing it
> goes to the chosen "noise" patch.
> There are no apparent loose components or connectors. Everything
> seems to be in place. Where would you start the diagnostics
> for any help.