Vintage Simmons Drums (UK) Users Group

Hi list,

I brought out the SDS-III to check out what the hell is the problem I'd 
experienced with the outs.

Connecting all four pads to the DIN-5 pad socket all of them triggers 
the right channels and the separate outs are loud and clear.

When swithing to mix out channel 3 and 4 still produce sounds but 1 and 
2 turns silent. I've eliminated all obvious things like grounding and 
dirty sockets, loose wires etc.

When fiddling with the effect switches on channel 1 I realise that it 
_sometimes_ feeds the signal to the mix out. The problem seems to be 
located in this part of the circuitry or even the switches themselves.

I'll dive into the schematics soon to see how it's rigged, but if anyone 
has any heureka moments out of this description, let me know. I focus on 
channel 1 since I get some results there and will assume that channel 2 
have some other issue I can deal with later.

Recent Ebay note:

A claptrap mk1 was sold on ebay Germany yesterday. 451 euros. Yesterday 
was a 70's e-drum evening with a Syncussion selling at 600+ and a 
Pollard twin at 407 (I know that exact figure 'cause I placed the 406, 
hoping to snatch the pedal and resell the synth). :S

cheers,
-- 
electronically yours, jesper

- -- --- ---- ----- ---- --- -- -
www.electronic-obsession.se

If the single outputs work and some of the channels appear on the mix output, you have (only) a problem with the wiring. I guess, some soldering points are rotten.
The channels signals are fed via a resistor 22k and this ugly big capacitor 0.47µf from emitter of the transistor T6 2N 5172 to the mix volume pot. You don't have to remove the whole PCB board from the housing to check this, you lucky man.
Try to re-solder the channel faders (!) and the big capacitors first.
Good luck

  ----- Original Message ----- 
  From: jesper 
  To: Simmons_Drums@yahoogroups.com 
  Sent: Monday, March 28, 2011 2:48 PM
  Subject: [Simmons Drums] SDS-III separate outs vs. mix out


    
  Hi list,

  I brought out the SDS-III to check out what the hell is the problem I'd 
  experienced with the outs.

  Connecting all four pads to the DIN-5 pad socket all of them triggers 
  the right channels and the separate outs are loud and clear.

  When swithing to mix out channel 3 and 4 still produce sounds but 1 and 
  2 turns silent. I've eliminated all obvious things like grounding and 
  dirty sockets, loose wires etc.

  When fiddling with the effect switches on channel 1 I realise that it 
  _sometimes_ feeds the signal to the mix out. The problem seems to be 
  located in this part of the circuitry or even the switches themselves.

  I'll dive into the schematics soon to see how it's rigged, but if anyone 
  has any heureka moments out of this description, let me know. I focus on 
  channel 1 since I get some results there and will assume that channel 2 
  have some other issue I can deal with later.

  Recent Ebay note:

  A claptrap mk1 was sold on ebay Germany yesterday. 451 euros. Yesterday 
  was a 70's e-drum evening with a Syncussion selling at 600+ and a 
  Pollard twin at 407 (I know that exact figure 'cause I placed the 406, 
  hoping to snatch the pedal and resell the synth). :S

  cheers,
  -- 
  electronically yours, jesper

  - -- --- ---- ----- ---- --- -- -
  www.electronic-obsession.se


  

[Non-text portions of this message have been removed]

Hi Michael, hi list,

I've dug further and was about to update when I saw your mail...

Michael Buchner skrev 2011-03-28 15:37:
> If the single outputs work and some of the channels appear on the mix
> output, you have (only) a problem with the wiring. I guess, some
> soldering points are rotten.

That's my guess too after examining the schematics. It might be the C12 
cap too or even the more unlikely case of rotten resistor (R59). What am 
I saying? A rotten resistor was the case in my SDS-IV when that was dead 
upon arrival...

> The channels signals are fed via a resistor 22k and this ugly big
> capacitor 0.47µf from emitter of the transistor T6 2N 5172 to the mix
> volume pot. You don't have to remove the whole PCB board from the
> housing to check this, you lucky man.
> Try to re-solder the channel faders (!) and the big capacitors first.
> Good luck

I think I'll removed the pcb anyway. That way I can visually inspect 
resistor and capacitor too.

Thanks Michael, I keep the list posted with the progress. But now it's 
time to pick up my little drummer at daycare...

-- 
electronically yours, jesper

- -- --- ---- ----- ---- --- -- -
www.electronic-obsession.se

>
> ----- Original Message -----
> From: jesper
> To: Simmons_Drums@yahoogroups.com <mailto:Simmons_Drums%40yahoogroups.com>
> Sent: Monday, March 28, 2011 2:48 PM
> Subject: [Simmons Drums] SDS-III separate outs vs. mix out
>
> Hi list,
>
> I brought out the SDS-III to check out what the hell is the problem I'd
> experienced with the outs.
>
> Connecting all four pads to the DIN-5 pad socket all of them triggers
> the right channels and the separate outs are loud and clear.
>
> When swithing to mix out channel 3 and 4 still produce sounds but 1 and
> 2 turns silent. I've eliminated all obvious things like grounding and
> dirty sockets, loose wires etc.
>
> When fiddling with the effect switches on channel 1 I realise that it
> _sometimes_ feeds the signal to the mix out. The problem seems to be
> located in this part of the circuitry or even the switches themselves.
>
> I'll dive into the schematics soon to see how it's rigged, but if anyone
> has any heureka moments out of this description, let me know. I focus on
> channel 1 since I get some results there and will assume that channel 2
> have some other issue I can deal with later.
>
> Recent Ebay note:
>
> A claptrap mk1 was sold on ebay Germany yesterday. 451 euros. Yesterday
> was a 70's e-drum evening with a Syncussion selling at 600+ and a
> Pollard twin at 407 (I know that exact figure 'cause I placed the 406,
> hoping to snatch the pedal and resell the synth). :S
>
> cheers,
> --
> electronically yours, jesper
>
> - -- --- ---- ----- ---- --- -- -
> www.electronic-obsession.se

...very flakey soldering and possible trace cuts/breakage at the bottom 
pcb-line. Nothing a few fly-wires can't fix I guess.

More later tonight I hope!

-- 
electronically yours, jesper

- -- --- ---- ----- ---- --- -- -
www.electronic-obsession.se

The feed from all four voices to the mix out is at the very bottom of 
the pcb. Each channel al fed there through the "ugly big cap". One cap 
had come loose and there were more than one break in the line itself. No 
wonder it didn't work!

A couple of fly-wires later it's up and running as expected. Now the 
task of replacing 50 nuts and 4 screws remain... :S

-- 
electronically yours, jesper

- -- --- ---- ----- ---- --- -- -
www.electronic-obsession.se

The cap is really ugly. Dave used a 0.47µF but suitable for 10000000 Volts or something. No idea why, may be he got these very cheap.
Good luck with the nuts, don't shortcut something on the backpanel. Duct tape helps (between PCB and the jacks...).
Yours
Michael

  ----- Original Message ----- 
  From: jesper 
  To: Simmons_Drums@yahoogroups.com 
  Sent: Monday, March 28, 2011 11:05 PM
  Subject: Final (?) update: Re: [Simmons Drums] SDS-III separate outs vs. mix out


    
  The feed from all four voices to the mix out is at the very bottom of 
  the pcb. Each channel al fed there through the "ugly big cap". One cap 
  had come loose and there were more than one break in the line itself. No 
  wonder it didn't work!

  A couple of fly-wires later it's up and running as expected. Now the 
  task of replacing 50 nuts and 4 screws remain... :S

  -- 
  electronically yours, jesper

  - -- --- ---- ----- ---- --- -- -
  www.electronic-obsession.se


  

[Non-text portions of this message have been removed]

Michael Buchner skrev 2011-03-29 01:38:
> The cap is really ugly. Dave used a 0.47µF but suitable for 10000000
> Volts or something. No idea why, may be he got these very cheap.
> Good luck with the nuts, don't shortcut something on the backpanel. Duct
> tape helps (between PCB and the jacks...).
> Yours
> Michael

It sure is ugly. Maybe he thought that since all drummers are morons 
they would feed weird stuff through the output or something...
One of the caps was slightly loose from the pcb resulting in bad 
connection. together with broken pcb traces it was the reason for 
everything. Three fly-wires later and everything kicks again.

I put Landscape on the record player and tweaked some sounds on the 
SDS-III, hooked up my bass amplifier and started hitting the pads. First 
real test with just drums and no sequencer involved. My conclusion is 
not just that it's (still) amazing, it's also not as bad when it comes 
to pad crosstalk as rumour has it.

And... the run generator is one really cool feature!

-- 
electronically yours, jesper

- -- --- ---- ----- ---- --- -- -
www.electronic-obsession.se