Vintage Synth Repair

Digikey??? Mouser??? Etc.????

 

From: vintagesynthrepair@yahoogroups.com
[mailto:vintagesynthrepair@yahoogroups.com] On Behalf Of rpcfender
Sent: Saturday, April 04, 2009 8:14 PM
To: vintagesynthrepair@yahoogroups.com
Subject: [vintagesynthrepair] Re: Emu Proteus 2000

 

Hi Alan
thanks for the great, detailed reply.
A friend with a can of cleaner/lubricant came over yesterday and I very
carefully sprayed it down the the shaft. It worked. I don't know if they are
mechanical or optical encoders. So it either moved some dirt from the
photo-interrupter or cleaned the tracks/contacts.

There is a cap on the main board and I thought it might be the big cap
instead of a battery deal, but it looks too small and I couldn't read it's
value.
Strangely, I noticed that there is the same Calibrate Knobs in the Master
edit area. I tried it here and it stored the offsets and was fine after
12hours off. Re did the calibration in the Diagnostic area and it failed.
Back to the Master area and it is now fine. Curious programming???

So although I am none the wiser, the unit is up and going well.
I just have to find something for the power switch.

Thanks for the help

Royce
> 
> I had an Extreme 1, which is similar to the EMu Proteus 2000, that had a
broken data wheel.  It is impossible to get a replacement.  Emu, or what's
left of them, directs requests for parts to a company in Florida that
doesn't answer e-mail.  They also want $80 up front just to look at any
problem with an EMu tone module.  They don't seem to be seriously interested
in repairing any broken units that are out there.  
>  
>   The data wheel is not a potentiometer, it's a data encoder.  That is
what allows it to spin endlessly in either direction.  The difference is
that a potentiometer is a variable resistor that outputs a proportional
voltage between the minimum and maximum values.  The data encoder puts out
two bits of digital information that indicates whether the knob has been
turned left or right one click.  The jumping around that the EMu tone
modules do when the data wheel is turned rapidly results from the EMu's
internal programming, not corrosion inside the wheel housing.  I suggest
that you turn it slower and be happy that it still works.
>  
> The data wheel is cheap plastic.  If the unit falls over and hits the
knob, it will break off and it is impossible to get a replacement.   I put
in another data encoder from a piece of broken medical equipment on my
broken EMu. But it took four clicks of the new encoder to match one click of
the original one.  This might be due to the fact that there are two types of
encoders: binary output and Gray code output.  In any event, the replacement
that I installed was much higher quality than the original data wheel, even
if it took four clicks for every one of the original.  I described the unit
in detail and sold it on eBay for $120 about a year ago.  I have an EMu
Audity 2000 now, but might sell that one soon also.  Despite all their
impressive stats and features, the EMu tone modules from the late 1990s such
as the Orbit, Planet Phatt, Mo' Phatt, Audity2000, and XR-1 are more like
sound effects boxes than actual useable musical instruments. 
> The Proteus 2000 may be the only exception of the series because its
samples are oriented around actual orchestral instruments.
>  
>   I don't recall if the EMu series has a backup battery.  Around the
mid-1990s the technology migrated from using batteries (to provide a
constant voltage to Static RAM chips that held the user-configuration
information) to using Flash EEPROM memory chips.  Flash memory allows
writing data quickly to the chip and retains the data when the power has
been turned off.  They can be written with new data many thousands of times.
Their big disadvantage is that bad data is stored through power cycles.
Sometimes the manufacturers will use Flash memory to store the operating
system of the synth unit.  This allows the OS to be upgraded by the user or
music-store technician without having to exchange memory ICs from the unit.
>  
>   Some manufacturers put the factory-preset voice parameters into Flash
memory which allows the users to overwrite them permanently.  Kawai did this
with the K1 and K1M. Most synth makers put the device OS and voice-presets
into ROM chips that can't be changed.  I have never been able to get a clear
answer from EMu about how their late-1990s modules work, since they don't
respond to technical questions any more.  They do have OS version updates on
their website.  As a last resort, try installing one of these specifically
for your Proteus 2000.
>  
>  Good Luck
>  
>   Alan Probandt   Portland Oregon USA
>