Vintage Synth Repair

Thanks man, the tuning procedure is exactly what I was missing. 

I've cleaned up all the connectors (on main board and sub boards); it didn't solve my issue, but it's a good start. I've also tipped on all chips & components to track any dry joint (I'd this issue on a Kurzweil 1000).
The issue really resides in the digital part during the init phase. Happily, I've got another DX7, in working condition; I can make some comparisons.


--- In vintagesynthrepair@yahoogroups.com, "z3sound" <z3sound@...> wrote:
>
> 
> hi 
> there was no complete Service manual for DX7 (first edition)
> on the internet.but now it is 
> i just upload the complete  DX-7 first service manual in Files
> hope it will help......
> 
> --- In vintagesynthrepair@yahoogroups.com, Kashayar Dashtdar <vdashtdar@> wrote:
> >
> > Hi my friend.
> > 
> > Unfortunately there is no complete Service manual for DX7 (first edition)
> > on the internet.
> > 
> > Try these :
> > 
> > 1- Replace all the electrolytic capacitors in the power supply board.
> > 2- Send a fresh sound bank from the PC to the keyboard using a midi
> > interface.
> > 
> > I hope it will make your dx7 work properly.
> > 
> > Good luck.
> > Ciro
> > 
> > On Tue, Mar 6, 2012 at 8:49 AM, alesisfusion8hd <babouche369@>wrote:
> > 
> > > **
> > >
> > >
> > > Hi group,
> > >
> > > I recently bought a first generation DX7 for $ 50. Problem on startup:
> > > sometimes starts up OK, sometimes keeps looping, sometimes seems OK but
> > > actually frozen.
> > > When it starts up OK, I found only garbage in the internal memory, but it
> > > works with the cartridge. It does not memorize my settings, and main output
> > > seems dead (headphone OK). I've suspected and replaced the battery cell.
> > > I was able to run the self tests up to test #5 (analog inputs), but I have
> > > no foot controller to complete this stage.
> > > I checked the PSU and the voltage source on the main board (+2.5V, +7.5V
> > > and +5AV) and everything is OK.
> > > I suspect a signal is missing on the sub-CPU (6805), or a defective RAM.
> > > I picked up the schematic and the service manual on Dave Benson's site,
> > > but it seems to be altered after page 20. All other services manual I found
> > > on the web has the same issue. Does anyone have a full copy of it?
> > >
> > > Thanks,
> > > François
> > >
> > >  
> > >
> >
>