emulatorII-list

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).

I would suggest that you swap the SSM with a another SSM from a working 
channel and do some testing again.

If  channel 4 continues to have the same problem, the problem is not with 
the SSM.

While you have the E2+ open, try pressing down all chips ( beware of static 
!!! and do not have the E2+ connected to mainspower ) that are mounted in 
sockets.

I do not think this is a powersupply problem.

It is a heat-related problem for sure.....

WT


----- Original Message ----- 
From: "ajwills1972" <home@...>
To: <emulatorII-list@yahoogroups.com>
Sent: Monday, September 06, 2010 10:18 AM
Subject: [emulatorII-list] Advice request - Intermittment channel error


> 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).
>
>
>
> ------------------------------------
>
> Yahoo! Groups Links
>
>
>

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).
>

�

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).

Many thanks to everyone who replied. I will try the re-seating first, then the SSM swap-over if that doesn't work. The advice on rebuilding is also much appreciated, but it might be a few weeks before I have the time to do such a thorough re-build. Replacing caps has certainly helped on some of my other old gear...

All the best

Andy



--- In emulatorII-list@yahoogroups.com, Mike de Vries <mrjdevries@...> wrote:
>
> Open it up, and using a small flat head screwdriver, pry up each IC gently a few millimetres away from the IC holder, then press it down. (This is called re-seating the IC)
> This works the contacts on the IC holder, and can help fix up a poor connection between the IC and it's holder.
>  
> EII's are "notorious" for needing it's IC's reseated. Mine had a very similar problem, and this fixed it up immediately.
>  
> Obviously, do this WHILE THE MACHINE IS OFF AND UNPLUGGED.
>  
> It could be a problematic SSM IC, or many other things, but I'd start with the above.
>  
> Regards
> Mike
> 
>  
> 
>   
> 
> 
> 
> 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).
>

So, I was doing the IC reseating last night, and discovered that IC97 on the output board had pin 8 bent out and hence missing the IC socket. Not something I had done, but somehow had not noticed this on my previous inspection.

IC97 is demultiplexer on the sample/hold circuit, and pin 8 (Vss) is meant to be connected to pin 7 (Vee).

Having straightened the pin, the channel error seems to have stopped (so far). Of course, given the intermittment nature, I'll wait a bit more before declaring a success :-) And, probably, I should replace IC97 with a new part.

All the best, and thanks again to all those who helped.

Andy

--- In emulatorII-list@yahoogroups.com, "ajwills1972" <home@...> wrote:
>
> Many thanks to everyone who replied. I will try the re-seating first, then the SSM swap-over if that doesn't work. The advice on rebuilding is also much appreciated, but it might be a few weeks before I have the time to do such a thorough re-build. Replacing caps has certainly helped on some of my other old gear...
> 
> All the best
> 
> Andy
> 
> 
> 
> --- In emulatorII-list@yahoogroups.com, Mike de Vries <mrjdevries@> wrote:
> >
> > Open it up, and using a small flat head screwdriver, pry up each IC gently a few millimetres away from the IC holder, then press it down. (This is called re-seating the IC)
> > This works the contacts on the IC holder, and can help fix up a poor connection between the IC and it's holder.
> >  
> > EII's are "notorious" for needing it's IC's reseated. Mine had a very similar problem, and this fixed it up immediately.
> >  
> > Obviously, do this WHILE THE MACHINE IS OFF AND UNPLUGGED.
> >  
> > It could be a problematic SSM IC, or many other things, but I'd start with the above.
> >  
> > Regards
> > Mike
> > 
> >  
> > 
> >   
> > 
> > 
> > 
> > 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).
> >
>