Vintage Simmons Drums (UK) Users Group

by the way, I have a few carcasses in UK to check out ... 
but I'm not able to test anything.


----- Mail Original -----
De: "jesper" <jesper@electronic-obsession.se>
À: "Simmons Drums" <Simmons_Drums@yahoogroups.com>
Envoyé: Mardi 7 Décembre 2010 15h25:15 GMT +01:00 Amsterdam / Berlin / Berne / Rome / Stockholm / Vienne
Objet: 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