Author Topic: Modifying Grayhill PCB mounting Rotary Switches (Read 1272 times)

ruffrecords · « **on:** May 22, 2012, 06:36:34 PM »

I need two decks of 1 pole 12 way PCB mounted rotary switchery. In the UK I can get one deck or three decks of Grayhill 71 series from Audio Maintenance but not 2 decks. Don't really want to go to the bother of ordering through Mouser et al, paying lots of postage plus import duty etc etc so.......

Is it easy to take a 3 deck Grayhill 71 series PCB mounting switch and remove one deck? Anyone done this sort of thing?

Cheers

Ian

bruno2000 · « **Reply #1 on:** May 22, 2012, 07:59:19 PM »

Quote from: ruffrecords on May 22, 2012, 06:36:34 PM

I need two decks of 1 pole 12 way PCB mounted rotary switchery. In the UK I can get one deck or three decks of Grayhill 71 series from Audio Maintenance but not 2 decks. Don't really want to go to the bother of ordering through Mouser et al, paying lots of postage plus import duty etc etc so.......

Is it easy to take a 3 deck Grayhill 71 series PCB mounting switch and remove one deck? Anyone done this sort of thing?

Cheers

Ian

I've taken apart several Grayhills, and they are pretty much a PITA to deal with. I believe there is a solid bar through the center of the switch that connects all of the rotating wafers. Since it goes through all three, I believe that you would have to cut it in order to get the back plate on.
Why not just either rotate the last section so that the PC pins are pointing up (if you've already got the board made) or just mount it like it is, and don't use one section?
Best,
Bruno2000

ruffrecords · « **Reply #2 on:** May 22, 2012, 08:04:20 PM »

Thanks for the tip Bruno. The PCB is already made so I'll try rotating the third section.

Cheers

Ian

shabtek · « **Reply #3 on:** May 23, 2012, 01:31:20 AM »

no the 71 series is not a solid bar---they are only a pita if they come apart, if you keep pressure on the stack of wafers, remove the nuts and then slide off the rear keeper and wafer then replace the rear keeper\cap and nuts it will be ok...if a contact\rotor thing falls out it can become a PITA quickly.
I always like to practice\ reacquaint on a spare before surgery.

Also the question always remains if reliability is compromised.

can you clip off the pins of the unused deck;

PS Ian
a generic pcb for multideck greyhill 71 would be the danglers

bruno2000 · « **Reply #4 on:** May 23, 2012, 07:57:12 AM »

What I would like info on, is modifying some Grayhills from continuous rotation to stopped rotation. Is it just a matter of drilling small holes on the front plate, ot is there more to it?
Thanks!
Best,
Bruno2000

horvitz · « **Reply #5 on:** May 23, 2012, 08:32:12 AM »

I've got a whole bunch of these in pieces right now. Would some pictures be helpful? I think the best option WRT reliability would be to clip pins or rotate the third deck.

Just whatever you do, don't remove the first deck from the front housing because then you'll have ball bearings and springs and bits coming apart and I'm not sure any normal human can get that back together correctly. At least, I can't!

Brian

RuudNL · « **Reply #6 on:** May 23, 2012, 09:12:20 AM »

I once disassembled a Grayhill switch, and ended up with half of the internal parts shot into the ceiling...
(The other half of the internal parts I never found back...)

bruno2000 · « **Reply #7 on:** May 23, 2012, 09:31:05 AM »

Quote from: horvitz on May 23, 2012, 08:32:12 AM

I've got a whole bunch of these in pieces right now. Would some pictures be helpful? I think the best option WRT reliability would be to clip pins or rotate the third deck.

Just whatever you do, don't remove the first deck from the front housing because then you'll have ball bearings and springs and bits coming apart and I'm not sure any normal human can get that back together correctly. At least, I can't!

Brian

Some photos would be great, thanks! I called Grayhill, and asked for some mechanical drawings of the innards, but no joy. I have had the front sections apart, and it took a LONG time to get it back together. You can take the front plate (with the threaded bushing) off without getting into trouble. I just use some gaffers' tape to hold the sections together when I disassemble.
Still looking for suggestions to incorporate stops in a continuous rotation switch.
Thanks!
Best,
Bruno2000

horvitz · « **Reply #8 on:** May 23, 2012, 10:22:13 AM »

Not sure what to tell you about adding a stop to a continuous rotation switch. Seems like major surgery to me..

I'll grab some pictures of a few different configurations this evening and show how they all go together.

ruffrecords · « **Reply #9 on:** May 23, 2012, 11:27:10 AM »

Quote from: shabtek on May 23, 2012, 01:31:20 AM

PS Ian
a generic pcb for multideck greyhill 71 would be the danglers

Do you mean one that brings out all the connections to pads you can wire to?

Cheers

Ian

ruffrecords · « **Reply #10 on:** May 23, 2012, 11:28:26 AM »

Quote from: bruno2000 on May 23, 2012, 07:57:12 AM

What I would like info on, is modifying some Grayhills from continuous rotation to stopped rotation. Is it just a matter of drilling small holes on the front plate, ot is there more to it?
Thanks!
Best,
Bruno2000

Is this different from setting the stops to restrict the total number of steps?

Cheers

Ian

dmp · « **Reply #11 on:** May 23, 2012, 11:48:04 AM »

Quote

What I would like info on, is modifying some Grayhills from continuous rotation to stopped rotation. Is it just a matter of drilling small holes on the front plate, or is there more to it?

I've taken apart salvaged 71 series grayhills to adapt to projects. I've found that even non-adjustable grayhills can have set stops by taking off the metal front plate and putting in pins. You do have to be careful that they don't explode with the spring and BBs - but having had several explode it is possible to get them put back together. The number of decks can be adapted too - the ones I've done this with are modular. If I recall correctly...

bruno2000 · « **Reply #12 on:** May 23, 2012, 01:44:36 PM »

Quote from: ruffrecords on May 23, 2012, 11:28:26 AM

Quote from: bruno2000 on May 23, 2012, 07:57:12 AM
What I would like info on, is modifying some Grayhills from continuous rotation to stopped rotation. Is it just a matter of drilling small holes on the front plate, ot is there more to it?
Thanks!
Best,
Bruno2000

Is this different from setting the stops to restrict the total number of steps?

Cheers

Ian

Yes, the "adjustable stop" switches have tiny holes in the front plate in which to insert pins that limit the rotation of the shaft. Grayhill also makes switches that have no holes in the front plate, so that rotation is continuous. I have some of those switches, and I'd like to mod them so that they have stops.
Best,
Bruno2000

ruffrecords · « **Reply #13 on:** May 23, 2012, 04:03:28 PM »

Quote from: bruno2000 on May 23, 2012, 01:44:36 PM

Yes, the "adjustable stop" switches have tiny holes in the front plate in which to insert pins that limit the rotation of the shaft. Grayhill also makes switches that have no holes in the front plate, so that rotation is continuous. I have some of those switches, and I'd like to mod them so that they have stops.
Best,
Bruno2000

Ah, now I understand. I have only seen the adjustable versions. I did not realise they did ones without out the holes. Sounds like a tough problem.

Cheers

Ian

horvitz · « **Reply #14 on:** May 23, 2012, 04:18:52 PM »

Actually not so bad, I think. As Dan said, if you carefully remove the front plate from the continuous rotation switch, you'll find the stop holes hiding behind and it looks like you can slide a pin in there (a bit of resistor leg fits well). Not surprised at all that GH would do this so that they can use the same parts on all of their switches. Here is a picture of exactly that:

horvitz · « **Reply #15 on:** May 23, 2012, 04:30:41 PM »

And here are some more gut shots.

With the modular assembly, the only unique feature of the multi-deck switches are the center shaft and the screws holding it together. Back to Ian's original question, it would be very hard to accurately shorten the center shaft to turn a 3 deck switch into 2.

2-pole deck. Note normal position of the contacts relative to the center shaft. Probably doesn't matter, but this is how the factory ships them. Those little contacts like to fall out. If you need to put one back in, the nub points to the rear where it makes contact with the deck itself. Non-shorting contacts shown. I don't have a shorting switch open right now.

1-pole deck.

Deck itself installed over the contacts.

Rear cap is just the plastic part of another deck. End cover goes over this.

Hope this helps. Seems like this isn't new information for many, but it's good to have a reference.

**EDIT** Note: I lost all of these images off my server and don't have them anymore

horvitz · « **Reply #16 on:** May 23, 2012, 04:35:52 PM »

I guess I'll just make one more note. I think that taking these things apart and messing with them is really not a very good idea in any place where you need decent reliability. I'm sure there are all manner of construction tolerances and torques and whatnot that GH follows that we won't reproduce. I have certainly witnessed one of my frankenswitches fail because the contact got just very slightly bent in and wasn't quite touching in some positions.. Proceed with caution.

Brian

shabtek · « **Reply #17 on:** May 23, 2012, 05:37:57 PM »

Quote

Quote from: shabtek on Today at 01:31:20 am
PS Ian
a generic pcb for multideck greyhill 71 would be the danglers

Do you mean one that brings out all the connections to pads you can wire to?

Cheers

Ian

yes as well as holes to insert resistors--like what Jeff at CAPI has done, but the board should accommodate 10 decks or whatever fits--and can then be snapped apart to the desired number of decks.

+1 on compromised reliability--any time you disturb the rotor-contact parts of the assembly there will be serious potential for this, and do you really want to have to replace one of these after the ultra customization;

While I've seen differences in internal parts in the snap-action spring and ball portion:
I don't think I've seen a continuous shaft through all rotors--In all 71s I've taken to bits there is a little brass bar through the rotor that mates into the rotor of the adjacent deck.

good idea on taping the decks together when trying to get bushing piece off for stop adjustments, i usually hold the assembly together and push out one of the screws from the back with a spare screw and use the one displaced to push out the other so the decks stay in alignment-- then pull the bushing but hold the actuator shaft in place: if the shaft slides out then it will explode as the balls and spring get sprung.

horvitz · « **Reply #18 on:** May 23, 2012, 06:32:17 PM »

Quote from: shabtek on May 23, 2012, 05:37:57 PM

While I've seen differences in internal parts in the snap-action spring and ball portion:
I don't think I've seen a continuous shaft through all rotors--In all 71s I've taken to bits there is a little brass bar through the rotor that mates into the rotor of the adjacent deck.

I thought that's what you meant up above but wasn't sure. I guess I'm not surprised that they've used different construction methods, but the way you describe certainly seems a lot more convenient. More uniform parts.

bruno2000 · « **Reply #19 on:** May 24, 2012, 07:42:05 AM »

Quote from: horvitz on May 23, 2012, 04:30:41 PM

And here are some more gut shots.

With the modular assembly, the only unique feature of the multi-deck switches are the center shaft and the screws holding it together. Back to Ian's original question, it would be very hard to accurately shorten the center shaft to turn a 3 deck switch into 2.

This is what I'm talking about with the continuous shaft that goes through all of the rotors, which must be cut to eliminate one of the decks. Newer switches may have the more "modular" approach. The switches that I have are date coded 1980.
Best,
Bruno2000

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Author Topic: Modifying Grayhill PCB mounting Rotary Switches (Read 1272 times)