Vintage Simmons Drums (UK) Users Group

Rodney wrote:
> Hello all!
> 
> As a testament to the FINE engineering, and to the men & women who put
> these units together, and designed them:
> 
> I spent all day & all night working on this SDS7 unit, soldered a few
> connections back on the power transformers...and guess what?
> 
> THE UNIT POWERED BACK ON, AND ACTED LIKE IT IS WORKING!!!!!  IT WANTS
> TO LIVE!
> 
> Says something for the ruggedness & simplicity in these units!  Now
> all I need is a new data panel with the BIG INCREMENT/PROGRAMMING KNOB
> in working order...LARS, CAN YOU HELP A BROTHER OUT?!?!?!?!?!?!?

Is this the knob at the bottom left, below the LEDs?

It's an optical encoder, similar to that used in mice.  If you remove 
the four screws holding the programming panel on, and *carefully* lift 
the panel off, you should see a circular disc about 30mm across with 
alternating black and clear stripes.  There will be two LEDs sticking up 
from the board, at right angle to each other, that shine through the 
disc.  Underneath, there are two photodiodes.

When I got my SDS7 the knob was broken off, leaving just the optical 
disc bit in place.  I had someone at the college I went to turn up a new 
shaft out of a bit of thin brass rod.  If I hadn't had that available, I 
would have bodged it up with a long thin bolt and some nuts and washers.

Gordon.