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Discussion about the Korg PolySix synthesizer

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Re: [PolySix] EG and VCF not working after battery leakage

2014-05-28 by Bob Grieb


See if these functions can be controlled correctly when using patches
in memory.  If so, then the output from the CPU to the analog circuits
is OK.   Then you have a problem with reading the controls.
But if the sound is always the same with all programs, then the
output circuit is bad and maybe t is reading from the pots OK.
Did you try the DAC calibration test in the manual?  It would be helpful
to know if that is working OK.  Just the part where you try to get the
two LEDs to light up.

  Bob

From: "phil0065@yahoo.fr [PolySix]" <PolySix@yahoogroups.com>
To: PolySix@yahoogroups.com
Sent: Tuesday, May 27, 2014 6:02 PM
Subject: [PolySix] EG and VCF not working after battery leakage

 
Bonjour !
I am French and happy to join this group of Polysix owner. My old Polysix bought back in 1983 has been sleeping in the attic since 1990, until I have returned back now to my first love. Unfortunately I have discovered the battery leakage problem !

So I did the standard procedure (like many)
Spend a lot of time checking the lines on KLM-367 with plenty of leds on at start up.. 
Browse internet for hours (discover service manual, old crown, etc)…, change IC 30 & 31 … recheck continuity, still few leds on..
Recheck again, change all set of panel switches (vintage planet)..4 leds on... Bank B not working...
Check lines again, to get finally only leds A1 on start up. Great !

Unfortunately sound is not OK.

Tune seems OK, 6 voices are OK, voltages from power board are OK (15V, 5V -5V and -15V) all pots and switches seem to work except the 4x EG and 4x VCF pots which are not active!
I think at this stage it is useless to do the calibration procedure. Is there some indications, checking to start with to define if it is still a line/continuity problem or if electronic parts (IC, diode..) should be changed.

Thanks in advance for your help
Phil



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