12 position 1 pole 3 deck (?) rotary switch

[Conviction]

Hi everyone,

Found this pretty nice 4 channel preamp. 76dB of gain for each channel, nice input/output transformers & whatnot.

Originally the unit was rather advanced: a preamp/mixer with the possibility to combine either of the four channels plus some remote controlling functions. I successfully removed all these additional features. Seemed pointless to keep, plus all channels were also routed to a large Tuchel connector originally meant to connect a filter and/or limiter unit, which I don't have.

I was pretty pleased that I could do it without a schematic. All good - I thought.

Well. The gain controls for each channel - a 12 position 3 deck 1 pole (?) rotary switch connected to a resistor network - cracked when I turned them a couple of times. There's this little plastic wheel (see pictures) that simply came apart.

Any idea where to look for replacements? Are/where these a common brand?
Any suggestions welcome.

Best regards,
Olle

 

[Matt Nolan]

Farnell have rotary wafers that are similar - http://uk.farnell.com/nsf-controls/ma112n-454623-1-ma/wafer-ma-1pole-12-pos-30-deg/dp/146049

and the switch frame that holds them - http://uk.farnell.com/nsf-controls/mu-454882fpa-ma/mechanism-ma-30-deg-metal/dp/1165268

I'm sure there are other places too (including Russian Ebay sellers)

 

[Conviction]

Farnell have rotary wafers that are similar - http://uk.farnell.com/nsf-controls/ma112n-454623-1-ma/wafer-ma-1pole-12-pos-30-deg/dp/146049

and the switch frame that holds them - http://uk.farnell.com/nsf-controls/mu-454882fpa-ma/mechanism-ma-30-deg-metal/dp/1165268

I'm sure there are other places too (including Russian Ebay sellers)

Thanks Matt!

It would be ideal to replace just the rotary wafers, but perhaps that's a little too optimistic.

It's rather hard to work on this unit without a schematic, but I think I'll manage if I mark things up and change one at a time.

Best,
Olle

 

[emrr]

What is the function of that wafer closest to the panel?  Looks like almost all of it is shorted.  Perhaps it has a function you can skip? 

 

[Conviction]

Sharp-eyed, Doug. Thanks. I'll see if I can figure it out.  If only I had the schematic.

I ordered the NSF-wafers/decks from Farnell. That was a pretty penny but still way cheaper than the Neve-ish switches.

In the meantime, here's a photo of the amplifier boards. There's 3 identical for each pre-section, plus another one for driving each transformer coupled output. Convenient.

The transformers look like something Siemens could've made.