Dial glass cleaning: 1960s McIntosh tube tuners and tube tuner preamps

MR71.

Mcintosh-Dial-Glass-pulled-from-MR71-MR-71.jpg

Yikes! Is that yours? What type of fluid was used?
 
Which 409 model do you use? Can you provide a link to your model?

All surface
Multipurpose
Glass and Surface
Cleaner and Degreaser
Multipurpose is what I've always used. Used to come in a clear spray bottle, now it's in a white bottle. Purple in color.

I think the big thing here is using the right amount. Too little and you can get the haze off the glass. Too much and the liquid will wick behind the letters and game over. Proceed at your own risk.
 
Multipurpose is what I've always used. Used to come in a clear spray bottle, now it's in a white bottle. Purple in color.

I think the big thing here is using the right amount. Too little and you can get the haze off the glass. Too much and the liquid will wick behind the letters and game over. Proceed at your own risk.

I accidentally transposed the product names. Did you mean "Multi-surface" or "All purpose"? See product images below... Thanks!
81gGtrKhaqL._SY679_.jpg

81bmWnAYvRL._SY679_.jpg
 
Yes, I did both. The mx110 x series was a very delicate task, but my method was the same on both. the printing had more or less turned to dust in places on the X series. I didn't use any type of cleaner. A brand new uncontaminated microfiber cloth and the fog from my breath was enough to clear away the grime. But don't touch the printing at all, if you do, it will move like it's a water slide decal or worse, just disappear into white dust on your cloth or swab. It's very time consuming to get in there and close to the dial indices and between the numbers etc, I had a pack of small plastic handled fiber swabs that could fit between the indices and numbers and letters. I found them at my hobby store in the model railroading section. I've used them for watchmaking and cleaning vintage watch dials, hands, etc. in much the same way. It's just a very delicate and painstaking task.

Thanks everyone for the recommendations. Below is the result.

I used a microfiber cloth and fog from my breath per rollcentre's recommendation. It worked like a charm. The dial is now spotless and the 50 years of haze buildup is gone. The glass looks brand new. I'm glad I didn't have to buy a reproduction dial glass.

I first tested a small area and noted the dial paint didn't move. This gave me confidence to very lightly clean the entire surface, including the fragile dial paint (using the fog breath approach), and it worked perfectly. I didn't experience any lettering loss. I guess it really depends on how well the dial paint has survived and how gentle one is in cleaning it.

If the paint on your dial is compromised, you won't be able to touch the paint like I was able to do. So YMMV.

IMG_7333.jpg

IMG_7334.jpg
 
Nice work. I'll have to look into that cleaning method.

Can you post a link for the green LEDs you used for the dial? I couldn't find anything on the auction site for that type.
 
Can you post a link for the green LEDs you used for the dial? I couldn't find anything on the auction site for that type.

Link:
https://www.ebay.com/itm/CUSTOM-FUSE-LAMP-FOR-MARANTZ-MCINTOSH-SANSUI-OTHERS-/282817568448?

Vendor is QUA-CO Audio. (no affiliation)

There are drop down selections when ordering.

I selected as follows:

Length: "42mm"
Color: "Green"
Voltage: "6.3 VAC"

Important: tell the vendor it's for a McIntosh MX110. He custom makes them so they are optimized for your model.
 
Last edited:
I have an MR67 (my first mac) and some days ago I tried to clean the screen but I did not know how to remove the tuner knob (I felt afraid to break something), could someone tell me how to do it safely?
 
I've had some success wrapping a shoe string around the pot shaft behind the knob and pulling it off that way. Just a word of caution, it will probably fly off at high speed.... make sure your face and anything of value isn't in it's path. You could try a few drops of penetrating oil on the shaft as well, but it may just be wicked up by the felt washer, and be careful that it doesn't get too messy and end up on the black paint behind the glass. Best of luck
 
I've had some success wrapping a shoe string around the pot shaft behind the knob and pulling it off that way. Just a word of caution, it will probably fly off at high speed.... make sure your face and anything of value isn't in it's path. You could try a few drops of penetrating oil on the shaft as well, but it may just be wicked up by the felt washer, and be careful that it doesn't get too messy and end up on the black paint behind the glass. Best of luck
Thank you very much for answering, I have seen several posts where pictures of their devices appear with the knobs removed but they do not explain how to do it and it caused me some frustration not to be able to do it, I did not find any screws that were clogging it, I will try to do it taking all the precautions that you recommend me.
 
Back
Top Bottom