"Loose" McIntosh black rocker switches: can these be tightened or retensioned?

Discussion in 'McIntosh Audio' started by monkboughtlunch, May 6, 2017.

  1. clinic-audio

    clinic-audio all on YAMAHA untill 1990

    Messages:
    2,114
    Location:
    France
    What is the problem ? open them and delete them , you will see answers to your questions very fast
    This must be a highly guarded secret. I've asked around several times and... Nothing. to who did you ask this question ? what secret are you talking about ?
    Keep in mind that the foam you will buy should resist to any lube products you will use in these switches . There is no secret here . Very simple .
    Quality of the contacts inside these switches is also very important but you don't talk about them ....
    The foam is used only to avoid the knob to move . No other reason .
     

     

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  2. monkboughtlunch

    monkboughtlunch Super Member

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    1,810
    Thanks. Perhaps you can elaborate about this very simple procedure?

    1) "Open and delete them" - please explain the open and delete process as this is the central question. Are you saying the rocker cover needs to be removed?
    2) "the foam you buy should resist lube products" - that makes sense. What brand of foam do you recommend? And how is the foam best reapplied to the switch? Should the foam have a single sided adhesive backing? And is it one piece inserted all the way through from top to bottom?
     
  3. clinic-audio

    clinic-audio all on YAMAHA untill 1990

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    I will make a drawing to you with my computer and it will take me a week to do it , so please wait a little bit
     
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  4. smartin53

    smartin53 Active Member

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    There was foam behind these switches? :eek:
     
  5. monkboughtlunch

    monkboughtlunch Super Member

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    1,810
    How’s the drawing coming? :beerchug:
     
  6. monkboughtlunch

    monkboughtlunch Super Member

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    1,810

     

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  7. monkboughtlunch

    monkboughtlunch Super Member

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    1,810
    Were you able to get to the drawing? Thanks!
     
  8. monkboughtlunch

    monkboughtlunch Super Member

    Messages:
    1,810
    The rocker switches with the infamous crumbling foam were ubiquitous in the 1960s McIntosh gear lineup: C11, MA230, C22, MX110, MA5100 etc.

    I have not had much free time to play around with the MX110 and most of my tools are packed up.

    But tonight I decided to unbutton my MX110 and try and remove the foam behind the rocker switches and measure the foam strips in order to find a suitable replacement.

    After taking off the faceplate and depressing the rocker switches, I noticed that a steady stream of finely crumbled foam falls out each time a rocker button is pressed.

    So if you have a unit with rocker switches, chances are there is a lot of crumbled foam dust behind your faceplate.

    There appear to be two adhesive backing strips in each rocker switch. It's not clear if the original foam contained a backing on each side of the foam, or if there were two separate strips of foam -- each with backing on one side.

    I tried using tweezers and pliers with varying degrees of success. I was able to get a lot of matter out, but some of the adhesive backing remains behind the rocker switches. The challenge is the rocker covers don't appear to come off. If they did, cleanup and replacement would be a snap.

    I'm thinking to get the rest of the debris out, I may need to take off the bottom cover in order to get better access to the gap behind the rockers.

    There's probably some folks out there that have been through this process; however, the knowledge is not shared and there is virtually no info online about the best way to tackle this. So it's a lot of trial and error.

    More work is needed to get all the adhesive and rotted foam out.

    Below: Example of foam dust that falls out after depressing the rocker switch. If your foam has never been replaced, you may have a lot of foam dust behind your faceplate.

    IMG_7206.jpg

    Below: close up of two apparent adhesive backing strips removed from behind one rocker switch. Most of the strips don't come out this nicely.

    IMG_7201.jpg

    Below: most of the strips had to be tugged out to remove.

    IMG_7208.jpg

    Below: adhesive strips visible behind rocker switch

    IMG_7209.jpg
     
  9. mnmmt

    mnmmt AK Subscriber Subscriber

    Messages:
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    Location:
    Minnesota
    I've been eyeballing these on my MA230 and MX110. I only have one switch that is really loose, but I can definitely see all the crusty stuff behind there, and there is always a pile of that black crud that falls out if I take the face plate off.

    My thought is something on the order of thin moleskin (like you put on your feet for blisters) to try to worm in there once the old stuff is out, then slide off the adhesive to attach it to the rocker. I haven't tried this yet because the switches aren't too loose, and I know once I get the old stuff out, I'll have a heck of a time getting new stuff in there.

    I also see that the metal pin that forms the hinge (at least on my MA230) on the switches could be removed if I could round over the one end that is pinched to keep it in place. That would make it a snap to replace, but all of this stuff is so old and no longer available that I just leave well enough alone.
     
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  10. monkboughtlunch

    monkboughtlunch Super Member

    Messages:
    1,810
    Considering how popular the classic 1960s MAC gear is today and the focus on restoration, it's ironic that there isn't already a "sticky" or "how to" thread that details the process to remove the adhesive, clean out the foam behind the rocker and the recommended new replacement foam brand and install procedure.

    If I can figure it out, I will post recommendations. But it's surprising there isn't already an established knowledge base about this issue.

    A bunch of MAC models used these switches. That means there are a lot of loose, gummy switches and crumbled foam dust out there! If there is foam dust behind one's faceplate, the dust could work it's way to other areas (rotary switches, potentiometers, glass or components) of the preamp or integrated amp during shipment or when moved around the home. Not good!

    c22.jpg

    McIntosh MX-110 Preamp Tuner-A.jpg

    C11_Front_01.jpg

    MA230_Front_01.jpg

    mcintosh51002.jpg
     
    Last edited: Jan 24, 2018
  11. monkboughtlunch

    monkboughtlunch Super Member

    Messages:
    1,810
    It is odd that it appears to be a secret procedure. What's the big deal and why the secrecy? I've asked some repair places and they basically say send your unit in for refurb and they will swap out the foam behind the rocker switches. They don't really go into detail over the phone on how to do it or the materials needed for replacement. The problem is that my unit is already restored and doesn't need any recapping. I don't want to risk shipping somewhere to have just the foam replaced. That's something I would prefer to do at home to eliminate risk of shipping damage or theft in transit.
     

     

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  12. monkboughtlunch

    monkboughtlunch Super Member

    Messages:
    1,810
    I had two that were loose. What I found when I took of the faceplate was that even the ones that were not loose were disintegrating. Basically, the foam behind all the switches were toast -- regardless of whether loose or not.
     
  13. monkboughtlunch

    monkboughtlunch Super Member

    Messages:
    1,810
    Since the rocker itself is just a "window dressing" cover that pushes a 1960s "Fisher-style" slider switch beneath, it appears the optimum solution would allow the rod that holds the rockers to be removed. With the rocker covers off, the back of the rockers and the front of the slider switches could be completely cleaned of the massive foam and adhesive debris which has invariably rotted underneath. Then a new piece of foam could be affixed and the rocker cover reinstalled. If it's possible to do this, the result should make the rockers feel like a high quality new switch instead of sloppy, loose mushy garbage that releases more foam dust behind the faceplate each time a rocker button is depressed!

    I took some close up pictures (see below) of the horizontal rods that hold the rocker covers in place. The end of the rod is so tiny it's hard to see detail, but when I blow up the pictures, it appears that one end of each rod is crimped to prevent the rod from coming out. Can anyone confirm? The other end of the rod has a nail head.

    Has anyone tried removing the rods to remove the rocker covers? If so, would it entail cutting the (apparently) crimped end of the rods and thus rendering the rod no longer useable? If so, are replacement rods readily available at a hardware store? Is there a McIntosh document somewhere that lists the rod specifications in a bill of materials listing (perhaps even the manufacturer and part number of the rods)?

    In the MX110, it looks like there are two different lengths of rod. One size rod holds two rocker covers. The other size rod holds one rocker cover.

    I don't have my caliper handy, but I would imagine the rods are standard diameter with a nail head on one side. And does the opposite end of the rod need to have a special precut area to facilitate the ability to crimp one end to lock in the rod?

    Red arrows in pictures below show what appear to be crimped ends holding the rods in place. I'm guessing to remove the rods one would need to cut the crimped end and a new rod would need to be used when reinstalling.

    Thoughts?

    rocker1.jpg

    rocker2.jpg
     
    Last edited: Jan 26, 2018
  14. monkboughtlunch

    monkboughtlunch Super Member

    Messages:
    1,810
    What would be helpful is a McIntosh exploded parts diagram with part numbers and specs for the rods.

    I did find some info about the slider switch in the MX110 service manual. The slider switches were manufactured by Stackpole -- parts #SS-26 and #SS-50. Unclear if Stackpole made the rocker covers and rods as well.

    Unfortunately, it doesn't appear the service manual notes anything about the rods that hold the rocker covers in place. Is there another McIntosh resource for either the C11, C22, MX110, MA230 or MA5100 that shows an exploded parts diagram and lists the info about the rod parts and rocker cover parts that McIntosh used? I'm assuming McIntosh sourced the rods and rocker covers from a third party manufacturer / supplier.

    Below: screen capture from MX110 service manual

    stackpole.jpg
     
    Last edited: Jan 26, 2018
  15. monkboughtlunch

    monkboughtlunch Super Member

    Messages:
    1,810
    Did you actually remove the foam yourself, or were you only hypothesizing?
     
    Last edited: Jan 28, 2018
  16. clinic-audio

    clinic-audio all on YAMAHA untill 1990

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    2,114
    Location:
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    I think you don't have any idea about what I am able to do on a MCINTOSH product . I work on MCINTOSH unit over 42 years now , I have spare parts that are obsolete at factory today .
    I never had brain trouble with these kind of knobs .
    You are right and you don't need any help from me
    I will so , not make any drawing making me loosing time about your request when I have serious customers waiting for their unit
    over
     

     

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  17. monkboughtlunch

    monkboughtlunch Super Member

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    1,810
    KQL.jpg
     
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  18. TR6man98

    TR6man98 Well-Known Member

    Messages:
    732
    Location:
    Seattle, WA
    It is not clear from your pictures but it seems you could replace those "rods" with some kind of rivets.
    Could you measure the diameter and length with a calipers?
    Also, are switses easily removable with rocker covers attached?
    If so, you could use blind pop rivets to reinstall them; if not maybe hollow soft rivet that you crimp with pliers.
    See McMaster-Carr to learn and order rivets or other suitable hardware.
    Local hardware store might've them as wall.

    I am not surprised this is not in SM as factory would buy switches...

    Good luck.
     
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  19. monkboughtlunch

    monkboughtlunch Super Member

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    1,810
    Thanks -- what does "SM" stand for?
     
  20. TR6man98

    TR6man98 Well-Known Member

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    732
    Location:
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    Service Manual
     
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