so i own an old RE201 space echo by Roland. a common problem with these is the rotary switch losing contact after all those years. i’ve used contact spray on it a couple of times, but after 6-12 months the problem always comes back.
now from building sams tuner VCOs, i have one of these left:
does anyone have experience with replacing the rotary on the space echo with something like that?
i have found this site, where somebody just disassembled and cleaned the switch. as you can see on the pictures it’s quite a strange switch and i would prefer just replacing it:
so does anyone have an idea if / how using the alpha switch could work? i realize there are also ones with 2, 3 or 4 middle contacts, do i have to use one of those?
cheers
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Yeah, looks like you need a 12-position/4-deck switch, plus quite a bit of tinkering to connect the right positions on the right decks/sections (which the poster for some weird reason call “potis”). There’s no way to do that with a single 12-position switch, unless perhaps you wire it up with a bunch of relays.
You can get 4-deck rotary switches from e.g. mouser for $30-150 (!).
(But if you want to get creative, it looks like the rotary maps twelve positions to four actual switches, so you could just use a pot – either your switch and a bunch of resistors or even a real one – plus an 8-pin ATtiny, four relays, and maybe a some drive transistors depending on what relays you have. For extra bonus, add MIDI support (you may want to splurge on a Nano for that). Definitely less work than getting all the wires soldered to the right places 
)
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hm too bad i can’t use the switch i have. do you have a link to the mouser ones?
“poti” is used for “potentiometer” by german speaking people a lot.
i don’t want to get too creative, since it’s quite an expensive piece of equipment 
thanks for the reply anyway!
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Yeah, but a rotary switch isn’t a potentiometer
The cheapest thing I found on Mouser is 71B30-04B12S, which has the right electrical specs (below) but the datasheet link there goes to something else 
Use this link instead, that’s on the manufacturer’s site so should be correct. You may want to double-check the mechanical specs before ordering.
To find more options on Mouser, just search for “rotary switches” and then use their filter thing to select 12 positions and 4 decks.
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Should point out that I’m definitely not a “Only Use Original Parts” kind of guy (more “But Why, They Probably Suck” ) and have obviously not done this repair, so you may want to check various repair outlets to see what options they have (he mentions echofix.com in that article but they don’t seem to have any in stock right now).
(I mean, the repair guys probably just bought something off Mouser too and added a bit of markup, but at least you can complain if it’s not the right thing.)
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yeah thanks. i wrote an email to echofix already. could not find the rotary switch on their website though.
Hmm, I would probably find someone qualified to take apart and clean the switch. Like you said, it’s an expensive piece of equipment and a botched repair attempt could significantly lower the value.
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You don’t have to throw away the original switch, though, you can just give it a well-deserved vacation
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I tend towards the advice of @fredrik. You could “temporarily” remove the original selector according to the directions of the blog post. Minutely document the connections you remove. Then you’ll have the wire endings, labelled I hope, and you can extend them outside the case with hookup wire soldered to the ends. At that point you’re free to connect them up in any way you like, as long as your chosen connection scheme makes sense in the light of the selector tabulation in the blog post.
Should you want to restore the original selector, clean it carefully as suggested and then, when you’re confident it’s done right, remove your DIY selection gear and reverse the removal procedure on the original selector.
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So I just stumbled upon this, which is about another Roland device, and a very different kind of rotary switch, but is fun reading and involves an ATtiny used in a rather interesting way:
https://mitxela.com/projects/jv1080_encoder_repair
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interesting , even though the code part was beyond me . it was nice to see someone putting the time into saving a piece of equipment instead of scraping it . 24 days later , it is weird how I can totally miss posts even when I check in every day
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I missed this too! The older Roland switches do wear down after 15-20 years or so and no amount of cleaning will put back a surface but there is a company here in Edinburgh who specialize in repairs to old gear and mods. I’ve had Japanese transformers rewound for uk voltage and switches and pots refurbished with new parts for far less than an authentic part would cost.
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Hey, I may be a little late here, but thought I might give it a go. I recently found a space echo in a mumbai flea market for about usd 100. Every screw and switch was oxydised and jam-packed and rusted. I was able to get every screw loose and every switch moving, except the unforgiving rotary switch. It is so horribly jammed that even the nut wouldn’t move. I had to cut it open, scratching the entire faceplate 
I’ve tried contact cleaner, and wd-40 in vain.
So I wanna know from @klausklaerwerk and anyone else who can help, where can i go from here? I’d very much like to clean the switch and get it moving, but I haven’t the faintest clue as to how. If I had to buy a replacement, should I get the shorting kind or non-shorting kind?
Any input is appreciated!
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Replace with a make before break. Short of sitting in an ultrasonic bath of break cleaner for a long time and total disassembly I’m not sure how else to recover.
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Thanks for replying! So would this be a fine replacement? It’s the same one that @fredrik mentioned earlier.
I would still prefer cleaning the original switch and using it. From reading around some old forums, I found out that using a paper to clean up the corrosion between the decks of multi-deck rotary switches might help with that. I think I’ll try this with some isopropyl alcohol, and order a replacement part just in case.
I would just like to point out that the wafers on the chip seem like they’re phenolic material. I’m a novice, so I don’t really know what that means, but I read that this material tends to soak up liquids and it takes weeks for the it to evaporate out. Just in case someone else is facing a similar problem as mine.
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