Vintage Simmons Drums (UK) Users Group

As the LED's are driven by IC2 and IC3, I'd definitely suspect one of them.  IC3 is just inverting the outputs from IC2 so I think you're going to be correct with IC2.

First of all I'd check that the solder connections for power to both chips are ok (14556 - pins 8/16 & 4011 - pins 7/14)

--- In Simmons_Drums@yahoogroups.com, jesper <jesper@...> wrote:
>
> philmurr skrev 2013-03-03 20:11:
> > I'm very happy my IV is working, next up is the SDS-V...
> 
> Speaking of which...
> 
> Can the tech guys here enlighten me regarding the program selector 
> switches? I _guess_ the four switches end up at the same IC which opens 
> the selected path... My hihat card works great upon startup if I stay 
> with the factory preset. If I choose anything else it turns weird. 
> Sometimes it plays some odd form of mix of all the presets but mostly 
> it's just a lame and dull sound coming out. The LEDs either light up all 
> or none. After fiften minutes or so it works as it should. It might be a 
> bad soldering joint since heat might help...
> 
> I dug out the schematics and looking at that crappy copy it looks as if 
> the IC2 (14556) might be the culprit. IC1 is a 4013 btw. Any input from 
> you soldering guys?
> 
> -- 
> electronically yours, jesper
> 
> - -- --- ---- ----- ---- --- -- -
> www.electronic-obsession.se
>