Hi Will,
congratulations! I should adjust the Chorus/Tremolo section of mine, too. Any advice how to do it? Any caveats? I wouldn´t want to haul my CS around just for that minor bit of surgery...
Stephen
____________________________________________________________________
"Ambition makes you look pretty ugly, kicking squealing Gucci little piggy." (Thom Yorke/Radiohead -- "Paranoid Android")
Stephen Parsick live in concert: Bochum Planetarium (Germany), 13th of December, 2008, 08:00 pm.
Finally available: Stephen Parsick -- Traces of the Past Redux, reissued with three previously unreleased bonus tracks. For more info please check www.parsick.com
For legal downloads please check:
http://www.musiczeit.com/directory.php?artist=296&title=Stephen+Parsick ----- Original Message -----
From: willgregori
To: yamahacs80@yahoogroups.com
Sent: Saturday, January 24, 2009 5:12 PM
Subject: [yamahacs80] CS80 1271 back on duty...
Dear CS-80 friends,
just want to report that my CS-80 no. 1271 has been successfully
resurrected. I bought it 8 years ago from a guy in switzerland who had
it sitting around probably more than 20 years without any service in
his garage. Shame on me, I found no time earlier to take care of this
baby, but now it plays like new again!
Needless to say, I am pretty impressed by the quality and depth of its
sound when fully calibrated to factory specs.
Since this was my first CS80 to take care of, let me share my
experiences when going through the complete tuning procedure:
1) Some Keys had no velocity: First I suspected some damaged 4000 chips
and started swapping these on the TSB boards- until i noticed that the
reason was actually some bend metal contacts on the Key sensors, grrr!
Re-aligning the contacts helped immediately.
2)Following the tuning procedure I stucked quite early because the
voltages on the KAS board seemed way off what should be right and could
not be adjusted with the VR trimmers to factory spec. It took me quite
some time to realize that I was using the wrong ground for this
measurement, I took electrical ground straight from the PSU- but when
taking the ground directly from KAS board it read out the proper
Voltages perfectly. So from then, I always pick up ground from the card
I am working on, not the PSU ground.
3) Pitchbend did not work: Changed CA3140 on BA board
4) Reference tuning Voltage on KAS board dropped from 4 Volts to 0
Volts suddenly: Broken TR29 on BA board.
5) Reference tuning voltage on KAS board suddenly went to 8 Volts:
Broken 4069 clock
6) enevelopes sounds different for VCA and VCF on each Voice, and some
Voices had no attack at all. First I suspected some broken ENV chip
here. The complete alignement of the envelopes is a quite elaborate
procedure. I had to buy a digital oscilloscope for it and go thru the
procedure several times, but finally everything could be adjusted
without the need of exchanging ENV chips.
7) Output level of Voice cards was different for each voice. Adjusting
the levels to factory specs (VCA gain should be 80mV) resulted in a
very low general output level, so I suspect this value is wrong. I just
increased the level up to 200-300mV, just before it starts clipping the
chorus and ensemble section. Now the output is much hotter and SN ratio
of Effect section much better.
8) Effect section: The adjustment procedure for the chorus and ensemble
section seemed not to work well on my particular unit, so I adjusted
this by ear to a minimum of noise and a reasonable effect level,
skipping the specified values here.
9) Tuning of Voice boards: Looking on my Voice boards I found no
temperature compensation diode, it is printed on the board but not
fitted. But tuning my unit was quite easy finally, after completing the
tuning procedure it is in tune immediately when switched on and stays
like this pretty well. It seems I have some magic VCOs...
Now the only issue left is to replace a bulb in on of the program
buttons, but this should be not a big problem,
cheers, Gregor
[Non-text portions of this message have been removed]