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

Audio Classics replaced the foam on mine.

How does the replacement foam material feel? Do all the switches feel smooth and fluid now? If you happen to take off your faceplate to change dial lighting for LEDs, would you be happy to post some images of your replacement foam behind the rockers? I'm curious if it is single sided or double-sided mylar and if one piece was inserted from top to bottom -- or if there are two separate pieces (i.e. one pushed up from bottom and one pushed down from top).
 
Have you tried to call Audio classic and order new switches? You could also ask for advice.
Looking at your pic. 1 (post #53) I see no way switch would be riveted to chassis.
More like silver base of each switch tabs into the slots in the face plate.
Pic 2 shows some bent end tabs holding the board with wire connections
Hard to see but could that be what holds switch to the chassis?
Good luck
 
Have you tried to call Audio classic and order new switches? You could also ask for advice.
Looking at your pic. 1 (post #53) I see no way switch would be riveted to chassis.
More like silver base of each switch tabs into the slots in the face plate.
Pic 2 shows some bent end tabs holding the board with wire connections
Hard to see but could that be what holds switch to the chassis?
Good luck

Thanks. After studying this issue, I think there are three unique solutions to the foam rot issue:

a) Pull mylar out with tweezers and shop vac the foam dust out. Live with the loose, wobbly rocker switches
b) Try and stuff new foam in the top and bottom of rocker opening (without removing the rocker cover)
c) Cut the crimped ends off the rivet bars holding the rockers in place. Pull out the rivet bars. Remove the rocker covers. Then clean back of rocker covers and front of slider switches. Apply new foam to back of rocker. Then replace rockers and install new replacement rivet bars.

Option "C" is the most involved, but should restore the unit to original "like new" switch performance. The challenge is that option "C" requires sourcing a suitable cutting instrument as well replacement rivet bars and adhesive foam with mylar protective sheaths sandwiching the foam.
 
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I think you’re going to encounter problems with both materials. Why? One side needs to have an adhesive film to adhere to the portion of the rocker you outlined in red in a previous post (see image below I “borrowed” from you) ... Both materials seem to have this. However.....pretty sure other side that actually contacts the slide switch protuberance needs to be a slick/tough film like Mylar so that it “slips” across the protuberance surface. The raw foam has a high coef of friction and I suspect it will bind w/o this film interface.

FWIW, when I removed the foam residue from my rockers, a length of film came out of each one. I assume this is the film I note above.

Curious to see how this all works out for you. I chose to accept a little slop in my switches since I couldn’t figure out how to replace the foam w/o also jeopardizing the switch itself. IOW, not worth the effort and hazard. YMMV

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Do you think this material might work?

https://www.tmhardware.com/Weatherstripping-Tape-Mylar-Backed-Self-Adhesive-Vinyl-Camper-Tape.html

Weatherstripping Tape, Mylar Backed Self-Adhesive Sponge Vinyl Camper Tape, 30 Ft. Roll

This Self-Adhesive Weatherstripping / Camper Tape is made of high quality Mylar Backed Closed Cell Sponge Vinyl. It is specifically designed to be applied as a seal between a camper and truck bed. Can also be used as a general Mylar backed weatherstrip where Mylar backing is desired, such as for door jamb and header sealing.

Dimensions: Tape measures 1-1/4" Wide x 3/16" Thick and comes in rolls of 30' Length.

Installation: Self-Adhesive Backing ensures simple, hassle free installation.
  • Closed Cell Sponge Vinyl Material
  • Mylar Backing
  • Self-Adhesive Backing for Easy Application
  • Designed to Seal Camper and Truck Bed
  • Sold in Rolls of 30'
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RollTape_Wide_(LR).jpg
 
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The hinge rods that allow the rocker covers to rotate appear to be hollow end rivets. It appears as though McIntosh cut the tail end of the rivet with a dremel half way. This allows for easy crimping to lock it in place.

I'm thinking the crimped ends could be cut off with a dremel and a new hollow end rivet could be used to replace the original.

rocker.jpg
 
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Do you think this material might work?

https://www.tmhardware.com/Weatherstripping-Tape-Mylar-Backed-Self-Adhesive-Vinyl-Camper-Tape.html

Weatherstripping Tape, Mylar Backed Self-Adhesive Sponge Vinyl Camper Tape, 30 Ft. Roll

This Self-Adhesive Weatherstripping / Camper Tape is made of high quality Mylar Backed Closed Cell Sponge Vinyl. It is specifically designed to be applied as a seal between a camper and truck bed. Can also be used as a general Mylar backed weatherstrip where Mylar backing is desired, such as for door jamb and header sealing.

Dimensions: Tape measures 1-1/4" Wide x 3/16" Thick and comes in rolls of 30' Length.

Installation: Self-Adhesive Backing ensures simple, hassle free installation.
  • Closed Cell Sponge Vinyl Material
  • Mylar Backing
  • Self-Adhesive Backing for Easy Application
  • Designed to Seal Camper and Truck Bed
  • Sold in Rolls of 30'
View attachment 1103906

View attachment 1103908

It might. However............from dimensions noted, if you try to use this stuff you’re going to be doing a lot of trimming.
 
I measured the hollow rivets with a caliper (per below photo) and they appear to be 3/32" in diameter. It appears the length McIntosh used is approximately 1" for the two rivets holding two rockers and 1/2" for the two rivets holding one rocker. (There are six total rockers on the MX110).

However, I'm not seeing any hollow 3/32" diameter hollow rivets in in either 1" or 1/2" lengths when I search online.

I wonder If there could be a better a approach. Instead of using four rivets, is there a solution in which there are only two fastener rods, each holding three rockers? If so, each of the two rods would need to be at least 1.5" long. Since there is empty space on either side of each three-rocker array on the MX110, the fastener rod could be longer than 1.5" long (no obstructions).

Thoughts on any fasteners that are this long or slightly longer? And is there a fastener that would not need to be crimped? Perhaps one end could plug in or screw in to lock in place and allow it to be reused if foam goes bad again in the future?

IMG_7618.jpg
 
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Progress update. Nearly complete. If you have a C22, MX110, C11, MA230 or MA5100 with loose and/or scarred rocker covers, this solution may interest you.

I originally planned to make this repair given the loose, sloppy feel of the rocker buttons and rotted foam. I took the opportunity to install new rocker covers as the old ones were scarred with scratches and fingernail indentions. You could just as easily keep your original rocker covers if you are happy with them.

Tools used:
  • Oscillating multi-tool with metal cutting blade (e.g. Dremel MM40-05 Multi-Max).
  • Scissors or exacto knife
  • Shop vac
Parts:
  • K&S Precision Metals #9820 2mm brass tube
  • New McIntosh C22 reissue rocker covers #07159700
  • Pemko Camper Tape PEM-P480 (mylar backed closed cell vinyl sponge tape, waterproof)
  • 99% isopropyl alcohol
  • Cotton swabs
  • Rubber Cement
Steps:
  • Use an oscillating multi-tool to drill through the solid rivets, which have hollow crimped ends.
  • Vacuum metal debris
  • Use 99% isopropyl alcohol to remove glue and foam from the slider switches (and old rocker covers if you reuse them)
  • Cut foam to size and adhere with rubber cement (or a superior adhesive) to back of rocker covers
  • Cut 2mm brass tube to size. You will need to cut four pieces total because the potentiometers make it impossible to thread two long pieces of tubing. Instead you need one medium and one short length of tubing per side -- totaling four pieces.
  • Install new rocker covers and insert 2mm brass tubing
  • Crimp ends of brass tubes
Below: multi-tool cutting rivets to extract the old rocker covers

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Below: The elusive slider switches finally revealed.

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Below: Vacuuming debris

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Below: The old tired, scarred rocker covers

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Below: New C22 rocker cover sitting on top of extracted 1960s MX110 rocker cover for comparison. New cover appears to be virtually identical to vintage.

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Below: testing the fit of K&S 2mm brass tube through the pivot hole of brand new rocker cover.

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Below: Experimenting with the Pemko P480 camper tape using an old rocker cover in order to match the old glue marks for sizing. This tape has an adhesive side which faces the back of the rocker cover. In addition, the tape has a mylar protective coating which faces the slider switch. I discovered that adhesive on the Pemko facing the rocker cover will need to be supplemented. I'm thinking rubber cement may work but I haven't yet tested it. You can tell from the yellow gunk on the old rocker covers that McIntosh also had to use some type of extra glue material to lock down the foam.

IMG_7907.jpg

Below: clean debris off of the slider switches.

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Below: Confirming the brand new C22 rocker cover will fit with the 2mm K&S brass tube. The new rocker cover is fresh and unscarred by decades of fingernail indentions!

newcover.jpg

Next steps: I need to find a suitable adhesive to bind foam and plastic. Would rubber cement be best?

After I have the new foam firmly secured, I will install the new covers, crimp the tubing and button it back up.
 
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My tools are packed up at the moment. Would a basic pair of cutting pliers likely generate enough force to cut off the crimped end? Or would another tool be better suited for the task? I want to prevent damage to the plastic structure holding the rocker and rivet. See pic below.

View attachment 1099236

It looks like there's enough "meat" on the end of the rivet where you could crimp it back enough to slide the rivet out. Then crimp it back when you're done. Tedious but not impossible.
 
It looks like there's enough "meat" on the end of the rivet where you could crimp it back enough to slide the rivet out. Then crimp it back when you're done. Tedious but not impossible.

I looked closely and it was virtually impossible to round the crimped ends and reuse. Much easier to get a new 2mm brass tube. See post #68.
 
One thing I noticed after the rockers were removed is that each of the six slider switches has a different level of resistance. I'm assuming that is not normal. I'm guessing they should all slide with similar resistance when brand new. Do I need to hit those sliders with a spray of faderlube (accessing from under the chassis) to add some lube and deox?
 
Hey, All. I’m restoring a C22 now and have run into the floppy switch syndrome after removing the dried foam. Instead of hacking at the switch covers to open them and install more adhesive foam inside, I’ve come up with a simper solution. Simply get some adhesive foam from Home Depot or Lowes, etc, and place four strips cut to the appropriate size where the plastic switches “land” when closed. This should be a reliable fix that’s easy to remove and repair in the future. Additionally, it provides for a very luxurious, damped feel when using the switches. I’m not at my workbench now, but I believe the foam thickness I used is 1/4”. I can verify this if anyone requires more detail. It’ll be a few days before I button the restoration up, so I’ll have an opportunity to see how this holds up, but I don’t expect any problems.

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Hi all. I've put my MA 5100 on the bench to address a balance issue (left channel louder than right) and want to clean all pots and switches first. I found this thread and have some ideas. I was able to squeeze the crimped end of one of the original rods (they are hollow) so that I could stick a flat head screwdriver on the other end and remove the pin so that I can clean off the old foam tape and apply something new. These crimped ends do not need to be cutoff with a dremel or otherwise. I used needle nose pliers to squeeze the crimp. Doing so does destroy some of the crimp, so reusing the original rods is not likely. I'm leaning towards finding small diameter cotter pins that I can cut to length for the two required sizes. But I will otherwise try and locate the 2mm brass tubing that was suggested above.

Other observations, the rockers are not perfectly symmetrical. The top side of the rocker appears to be 1-2 mm longer than the bottom, so make sure they are re-installed in the correct manner. Not sure why they would differ, other than to show a larger rocker face from the top of the unit when looking down.

Here are a couple pics of the one rocker I removed. I will post updates as I progress.
 

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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
Wow 42 years!? .. What a unique contribution you just made to this community.
 
Adding to an older thread, but thought I'd include some more information and pictures for those looking to rebuild their switches. I followed using some of monkboughtlunch's directions. I'm just starting some work on a non-operational MX-110Z I purchased and decided to tackle the switches while waiting on other parts.

I cut the old rivets out, but I just used small flush cutters like these from Harbor Freight. The rivets are fairly soft so it's not too hard to cut the crimp off and then pull them out. https://www.harborfreight.com/5-in-precision-flush-cutter-57794.html?_br_psugg_q=wire+cutter

The original rivets are 0.86" or 2.18mm in diameter. I ordered 2mm OD 0.5mm wall brass tubing which fit a little loose but with the foam it works well, 7/8" OD might be ideal. The 0.5mm wall is maybe a little extreme and made it hard to crimp the ends. I bought the thicker wall thinking about strength and life, but I think you could use thinner. https://a.co/d/3RZrQ3c

For foam, I used 1/4" wide 1/8" thick single side adhesive weather strip foam. I based measurement off the original pieces which I had removed and seems to fit very nice. https://a.co/d/d3AsA8C

So with all parts got everything laid out and I cut the brass to match the original lengths of the rivets with a 1/2" short and 1" long piece for each side. Later, after having trouble crimping I decided to go with a longer 1.7" to stretch across all 3 switches on each side.

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It was mentioned before, the switches might look symmetrical, but they're not. The bottom side is a little deeper than the top, you can tell after installing if you put them in wrong as the pressed in side of the switch won't be parallel to the face.

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The foam length is about 1-3/8" long. To help install the foam I used a flathead to push it up into corners.

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Install the switches and slide the brass rods through.

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The action on the switch is much nicer now and I don't have foam crumbs falling out.
 
When I do these, I glue mylar on the switch side of the foam, just like the originals. I think that you will find that the sharp corners of the switch will eat into the foam after a while. View attachment 2929199

Agreed. Steer clear of traditional foam which will rot and crumble. That's why I recommended Pemko P480, which is mylar-backed vinyl. In post #64, I included a link where one can buy the Pemko P480 tape:

 
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