Service woes - Siel dk600

[|||| Philip ||||]

I have a dk-600 and it is the best filter-quality-sounding poly I have
heard. (CS-50/60/80 Ju-6/60/106/Alpha jp4/6 m-1000 mw1/2) What sets it apart
is   the way the SSM-2044 filter sounds and sweeps with resonance and
pre-resonance settings. Of course it has minimal architecture that cripples
its power as a synthesizer however its sparkling sound quality is awesome.
The filter makes it very nice to use when I need a polyphonic part for a
song.

Unfortunately my dk-600 is also faulty. I received it with all working
except for the patch memory. I opened it up and noticed the leaking battery.
I cleaned it up, replaced battery, repaired traces, cleaned all socketed
IC's and jumper connectors however it still has the same problem: the
patches can be played manually and stored in memory however when they are
recalled, they sound correct however there are random snaps of loud static
bursts. It seems like the Res is going from it's setting to 100% then back
to normal again within a few ms. I thought it may be the knob reading
circuitry however it seems to work in manual mode (which is how I run it).

The other problem is that you can not calibrate the cutoff freq. Six voices
can be calibrated for the cutoff slider but once you add kbd track it goes
out again. Likewise if you calibrate it for slider and keytrack, assigning
envelope knocks the cutoff out of wack again! I just made a best fit
calibration with kbrd and env assigned...I will never play a sine solo with
just self-resonance on this thing ;)

I do not have schematics.

Philip

PS the synth is very frail and plastic abounds. Mine had 7 smashed keys and
the end pieces were busted on arrival.



----- Original Message -----
From: Greg Montalbano <Greg.Montalbano at ucop.edu>
To: <synth-diy at node12b53.a2000.nl>
Sent: Tuesday, April 18, 2000 5:14 PM
Subject: Service woes - Siel dk600


> Well, I've about had it;  been building & servicing synth devices since
> about 1980, and I've NEVER had as much grief as I've had from this
> @*&#%$&^%$ dk600 -- I'm just about THIS CLOSE to giving up & using the
> thing for a boat anchor.
>
> (or, more realistically, taking the voice board & creating my own synth
> from that)
>
> Before I do, has anyone out there had experience with these?  The ORIGINAL
> problem was with reading the control board pots & switches -- random data.
> After replacing a leaking backup battery, repairing destroyed board
traces,
> replacing affected ICs, and testing the ADC/DAC circuit and all
> connections, the problem remained.  I've swapped boards, swapped ROMs,
> tested the DIP connectors, and STILL the problem remains.
> Anyone had experience with this?
>
> Thanks.
>