Schadow Switch Replacement

[Morris]

Hello All, 

I've been working on restoring a bunch of WB470M channel strips, and obviously we ran into some issues sourcing replacement switches. After a lot of trial and error, I've managed to come up with a solution for the source select interlock switch bank, and the filter+phase switches. I designed some PCBs to retrofit smaller switches into the original footprint. I'll include photos below.

I have removed the Mic 2 option and replaced the Line and Mic switches with LED indicators, using a single switch to toggle between Mic/Line modes, sort of like in an 8078 Neve. 

I've also come up with a sensitivity pot replacement using an 11 position rotary switch. Feels very high quality and sounds great. The angle of rotation perfectly matches the position indicators on the front panel. 

Replacing these switches makes a huge difference in the reliability, noise and sound quality of the channels. If anyone is interested in having their switches replaced, feel free to contact me. 

[Morris]

Here are some additional photos of the work

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Manuals: https://drive.google.com/drive/u/2/folders/0B0yR0b5T78SKczBIcDgzZkstUjQ
 
Photos:
https://drive.google.com/drive/u/2/folders/0B0yR0b5T78SKd2JnQzlrckY2bWM
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[Anthony Kuzub]

This is EPIC!!!!

well done

[Anthony Kuzub]

what a tight design they had in there.  

Just a mess to untangle

well done.

this is like $10k worth of engineering work to replace what was once $2 switch.

What did you use as the switch for your sens?

Anthony

[Morris]

Thanks Anthony. It was a lot of work for sure. I had to start over a few times to get everything to fit correctly. 

For sensitivity, I used an NKK MRK112-BA miniature switch. I fitted it with a small circuit board and built the curve with SMD Thin-Film resistors for low distortion and noise. The switches feel really really good, very solid. 

I'm happy to provide these parts pre-built to anyone who wants them. Getting the switch bank out is a difficult job and the glue holding the copper clad to the PCB has deteriorated, so it's very easy to lift pads and even tear traces. It's a semi-advanced install, so you might want to have someone who's handy do the work. 

To view this discussion on the web visit https://groups.google.com/d/msgid/WBSps/4575381a-0a5d-4e64-9b3a-63b7d900ab1cn%40googlegroups.com.