Oh
BTW
Thank you David for your suggestions.....
I can't believe I forgot to mention that in my last post...
Once I can decipher the pin 40 jumper modification on the schematics
on the kas,I may feel braver in tackling the m Board rotating....
-----Original message-----
From: "Laurie Curry"
laurie@...
Date: Wed, 02 Apr 2008 21:18:36 -0700
To:
yamahacs80@yahoogroups.com
Subject: Re: [yamahacs80] I need 2 M cards
Is the waveshape chip very sensitive to heat when desoldering???
It is of course, one of the chips without an IC socket............
could it be socket mounted once out or would a socket create more
problems???
-----Original message-----
From: David Rogoff
david@...
Date: Wed, 02 Apr 2008 20:26:34 -0700
To:
yamahacs80@yahoogroups.com
Subject: Re: [yamahacs80] I need 2 M cards
slammah2006 wrote:
> I am down2 Oscillator cards in Bank 2 (# 3 and # 5) I believe it is
> the Waveshape chips that are faulty.....
> Does anyone have any spares,
Good luck
> or is know if there is a way to drop a
> voice out of the rotation giving 2 banks of 7 Oscillators???...If
that
> were the case I could move one from my first bank to bank 2...
>
This is pretty easy - I've done it before for someone while waiting
for
an oscillator chip. Move the bad parts to the highestvoice cards (e.g.
voice 8, then 7). Then you just jumper on the KAS board. If you look
at
the KAS chip description
(
http://www.therogoffs.com/cs80/manuals/CS80_Service_Manual/06%20-%20KAS%20ICs.jpg),
you can see that changing pin 40 (MODE) from -6.5 to +8.5v skips voice
8. If you have to disable more voices, then you need to change the
K01-K08 pins. Look at the difference between the CS80 KAS board
(
http://www.therogoffs.com/cs80/manuals/CS80_Service_Manual/04%20-%20KAS%20schematic.jpg)
and the CS80 KAS board (page 3 of
http://www.therogoffs.com/cs80/manuals/CS50_Service_Manual/Yamaha%20CS-50%20Service%20Manual%202%20of%202%20(%2011%20x%2017%20-%20Double%20Sided%20).PDF).
Note: when I did this, I just changed the MODE pin (by cutting the far
end of the resistor attached to it and connecting it to +8.5v) and
didn't tie the K08 pin. This caused the 8th voice to be on all the
time
and screwed up thetrigger to the Ring-Mod EG. I ended up pulling the
oscillator chips on the 8th voice M Cards to mute them. However, this
created a really weird side-effect. The waveshaper chip was still
there
and picked up the signal from the PWM oscillator. When the PWM rate
was
raised, it triggered the WSC and the oscillator was audible all the
time! Confused the hell out of me at the time.
David
[Non-text portions of this message have been removed]
[Non-text portions of this message have been removed]
){kind=link}
){kind=link}