emulatorII-list

Unfortunately, there is no magic bullet to fixing your problem.  Synths of this vintage have several components inside them that are well beyond their expected life and are very prone to failure.  Furthermore, failing parts stress good parts and could destroy irreplaceable components.

If you want to keep it from failing beyond repair, I strongly suggest investing some time, money, and energy into giving it the proper restoration that it deserves.  If you're not comfortable doing it yourself, take it to someone that can.

Regarding your issue at hand, you might be able to benefit from resetting all of the chips in their sockets - however, you are still playing on borrowed time unless you rebuild it.

My troubleshooting sequence after resetting the chips could be very long.

Here's a rough draft of what I would do and check if I just bought it off of E-Bay and I wanted to keep it for myself:

1.PSU rails present
2.PSU ripple
3.PSU load test 
4.Connection settings or continuity
5.board inspection (cracked joints, broken traces)
6.PSU Rebuild with all new caps (low ESR Electrolytic 105 Degree Celsius or Organic Polymer if available - these new organic polymer caps are awesome)
7.Replace all tantalum and electrolytic caps on all boards and disk drives
8.Check for flaky chips (too complicated to explain)
9.Check signal path for distortion or irregulatities 
10. Calibrate and set filter resonance.

-Mike

--- In emulatorII-list@yahoogroups.com, "ajwills1972" <home@...> wrote:
>
> Hi,
> 
> I have an Emulator II+ with an intermittment error on Channel 4. When the error occurs, you can play 7 notes in a row, the 8th note you play doesn't sound, and so on. I know it's a channel 4 error as I can use the channel disable function to turn off channel 4 and this makes the error go away reliably.
> 
> The intermittment aspect is that the machine never shows this error from cold, but will sometimes develop it after an hour or so of use. Turning off and on does not solve it. But leaving the machine off for about hour does. This is pretty reliable - in the sense the machine has developed the error several times and it always goes away again. It seems like heavy disk usage might be what precipitates the error -although not sure, and that might just be because of PSU load?
> 
> My guesses so far are:
> 
> 1. An intermittment fault on channel 4 - perhaps the SSM chip? (I note that the machine has one channel - not the faulty one - has an SSM chip with a different MCE code, so perhaps one has been replaced already?
> 
> 2. Some kind of power supply problem (due to this only happening when the machine is warm). 
> 
> But you guys know a lot more about this machine than I do. Any thoughts or advice would be much appreciated.
> 
> Best
> 
> Andy
> 
> P.S. Also trying to source the main board for the EMUCOMBOX project, but no stock in the UK at the moment (I see others have a similar problem).
>