Vintage Simmons Drums (UK) Users Group

I think I have only the frontpanel for the programmer.

Why did the battery burst ?

Did you install a diode when you swapped for the Lithium battery ?

WT
 
----- Original Message ----- 
From: "jesper" <jesper@...>
To: <Simmons_Drums@yahoogroups.com>
Sent: Tuesday, December 07, 2010 3:25 PM
Subject: Re: [Simmons Drums] SDS 7 Voice Card Reverse Engineering Project


>I know WT used to have one or more SDS-7 carcasses with the digital bits 
> intact (as I recall it). Anything left there? If so, it might be a 
> better way to solve the problem.
> 
> -- 
> electronically yours, jesper
> 
> - -- --- ---- ----- ---- --- -- -
> www.electronic-obsession.se
> 
> 
> brianwright23@... skrev 2010-12-07 07:42:
>> Hi, I'd like to introduce myself to the list and see if anyone out there
>> has access to a usable SDS 7 Service manual.
>>
>> My SDS 7 Saga :
>> About six months ago I restored an SDS7 which had been sitting on a
>> shelf with a burnt out power supply for many years. It worked flawlessly
>> with five voice cards for a few months when one day I came into the
>> studio and found it had lost it's memory. Turned out that the battery
>> for the digital memory had burst. I replaced it with a standard lithium
>> memory backup battery of the same voltage from Radio Shack. This
>> arrangement worked quite well for several more months, until that
>> battery also burst, this time with enough force to effectively destroy
>> both of the digital boards, (the ones located behind the keypad).
>>
>> In the course of rebuilding it the first time I got a pretty good sense
>> of the method whereby the parameters are transmitted to the individual
>> voices. There is a complex staircase-like waveform that has all the
>> analog voltage levels strung together, presumably to be de-multiplexed
>> by the "hybrid" module on each voice card.
>>
>> Now I'm entertaining the notion of embarking upon an effort to resurrect
>> the voices using a more modern digital control section, potentially with
>> midi control and pots or encoders, per parameter (15 of them). The main
>> roadblock at the moment is that I don't have a legible copy of the
>> Service Manual which had the circuit topologies. I do have the pdf scan
>> which is available at http://www.simmons.synth.net/sds7/
>> Unfortunately that scan is of low enough resolution that the important
>> details in the schematic sections are totally obscured.
>>
>> If anyone has, and would be willing to share, this information. That
>> would be wonderful. I would of course, in kind, return the fruit of
>> these efforts to the list, should those actually bear any usable reults.
>>
>> thanks,
>> Brian
> 
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