fix old fart string synth was Arp Quartet cheap?

WeAreAs1 at aol.com WeAreAs1 at aol.com
Fri Nov 5 06:04:49 CET 1999


In a message dated 11/4/99 8:49:17 PM, you wrote:

<<Speaking of cheap old string synths.  I have a stuck note on my Crumar
orchestron (fab bass).  I insulated the j wire contact but that does not
fix the problem, Anybody ever run across this problem ?  And solve it.>>

I don't have schematics for this particular unit, so I'm just guessing, 
but... Most of these types of keyboards have a key switching arrangelent that 
consists of the key, a couple of resistors, a single diode, and a capacitor.  
The capacitor is usually wired in such a way that it controls the release 
time of the key.  These capacitors are always either electrolytic or tantalum 
types.  Very often, the older tantalum caps from the 1970's and early 1980's 
tend to go bad.  If one of them goes bad in an ARP Omni or String Ensemble, 
it usually manifests as stuck notes.  Try changing out the cap that connects 
to the stuck key.  (you could test this by simply swapping it with the cap 
from an adjacent key)  Be sure to note the polarity of the cap when you 
replace it.

Keep in mind that if this is the problem, then more of these caps will 
probably go out in the future, and it might be a good idea to replace them en 
masse.

Let us know what you find, OK?

Michael Bacich




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