CS-01 sliders and other stuff...

[Johan Gustavsson]

Hello y'all!

Yesterday I made my debut as fault-finder inside a synth - By
measuring along test points and the like, I deduced that the filter
env amount slider inside my CS-01 was shot. Like, Whee! I'm a pro! :-)

Anyway, it looks like I need a replacement, and I wondered whether
anybody could help me. Farnell has a slide pot from ALPS (order
code.698-003) that looks the part in the catalog, but I have no
possibility to actually look at it, y'know. So, my question is: Does
anybody know whether that kind of pot is useful as a CS-01 replacement
(alt. Is there anywhere one could get more information (Primarily pin
configs) about these)?

Furthermore, while tracing signal flows around the PCB (It was quite
fun, understanding things like "Oh, this is a CV summing node, that is
a gate signal"), I realised that the res switch that says Hi/Lo
actually is on/off. The out from some section of the filter goes
through a trimmer, through the switch and back into the filter
input. When in the "lo" position, the signal is simply cut off, giving
no feedback at all. Anyway, this made me believe that it would be
rather easy to hack the CS to become in effect a CS-01II, by putting
an ordinary panel pot in series with the trimmer (there are some
convenient jumpers I could cut and patch into). Ok, so the 01II might
have a beefier filter altogether, but at least I'd gain a res knob
instead of that switch. I wouldn't want to replace the trimmer, since
it seems rather sensitive...I thought it was a bit too polite, so
turned the Q trimmer about 30 degrees CW and got a sound verging on
unusability (although it made a fairly good lead guitar sound through
the built-in speaker). It ended up somewhere around 10 degrees from
the original position. Whatever. Anybody got any comments or ideas on
why or why not to do this?

Even more, I found a part of the board to be completely unpopulated,
despite having traces and parts legends. What's that? One pot (that
wasn't there) was labelled "Noise amount". What would happen if one
were to fill that space? Questions, questions...:-)

Finally: I'd still like to have the amp env amount function
differently. At the moment, it works as an extra volume knob, giving
no sound at all at the bottom of the slider. I'd like that to be a
"Gate" kind of function, so that at the bottom it'd be a simple amp
on/off, and at the top it'd be fully contoured. Isn't it supposed to
work like that? When tracing signals, the only other thing that came
into the same summing point to the VCA was the breath control
thingy. Hmm...perhaps it ought to be a gate signal in at the bottom of
the slider, and the env in at the top? But I don't know how to make
that (Ok so I lied about finding the gate signals, ok? :->). Anybody
found the schemos out on the net somewhere?

Ah, well, that's todays question-hurling from me. Oh, got myself a
homepage, too. Not much synth stuff yet, but it's getting
there. Nice'n'bilingual, too, and no frames or animated gifs (in fact
no graphics at all, yet...:->). If you're interested, surf along to

	http://www-und.ind.liu.se/~johgu015/ 

Anyway, be hearing from you.
/Moxie (Now even more virtual)