[sdiy] strange symptoms

[gilwein at walla.co.il]

Hi.

I have that problematic Kawai SX210 which had it's battery leaking,
probably causing it to behave strangely like playing notes automatically
and playing a few notes when you hit only one key.

I clean all the defective are and replaced a few parts,
replaced the battery and resoldered a few wires.
also cleaned up the whole pcb.

Than it actually stopped playing automatically, 
and a few notes when you hit one key,
BUT, now it misses some notes sometimes,
and sometimes when you hit a chord
the sound comes out in pulses. Also it will play some notes
with a slightly different sound than the preset used.


I replaced a few capacitors and just when starting it up 
the dial wheel has stopped to respond and I now cannot edit
any of the parameters !!!

I noticed that there's a short between two transistor legs
that comes on and off  (the transistor is not leaking and is OK).

I mean sometimes the short is there but sometimes it is not .....

how can this be caused and is this normal ?

I also noticed that the EPROM chip and another (very) large
chip made by Intel, are getting warm after a few minutes of operation (but not too warm...)
is that normal ?

moreover, is there any chance that the EPROM programming 
has gone defected ?

Thanks,

I really want it to get fixed !

-----------------------------------------------------------------------
Walla! Mail, Get Your Private, Free E-mail from Walla! at:
http://mail.walla.co.il

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://synth-diy.org/pipermail/synth-diy/attachments/20031015/78b8659e/attachment.htm>