[sdiy] Crumar DS2 Problem

Julian Schmidt elfenjunge at gmx.net
Thu Aug 21 20:32:27 CEST 2003

I just followed the gate signal path back to the "memorized keyboard 
control" PCB inside the Crumar, where it's directly connected to a 
CD4093.  I'm going to replace all the ic's on this board, cause they 
are all still available.

further i checked the ADSR units by adding an external gate to the 
circuit. by doing this, the adsr changes from the hanging sustain to 
the release phase, no attack or decay phase at all. so i'm gettingt 
some new IC's for the adsr board as well, since its only a few bucks 
more on my order list an all ic's in the synth have sockets ;)

i hope the hanging note problem will be solved as well, when the 
keyboard controll  ic's are replaced ;)


Am 20.08.2003 um 21:00 schrieb Julian Schmidt:

>> jep, just checked, theres no gate signal arriving in the ADSR 
>> circuit. now i just got to find out where the keyboard circuit is. 
>> seems like there's the error, specialy when i think of the hanging 
>> key ;)
>> thanks for the tip.
>> julian
>> Am 20.08.2004 um 18:24 schrieb Peter Cooke:
>>> I had a Mono/Poly with a similar envelope problem - only the sustain
>>> seemd to work on the envelope section.  The problem was that the gate
>>> trigger was not reaching the ADSR circuit so it didn't know to reset
>>> for each new note played.
>>> Hope this helps
>>> -- 
>>> Thanks,
>>> Pete
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