McIntosh MC 2105 Pots repair for gain

[tomdowns]

After some experimentations and investigation think I found a solution in repairing the Gain controls on The Mcintosh MC 2105. I found that the drawings showed that the Potentiometer are part 134-191 250K ohm; yet I could not find these anywhere. I pulled apart my 2105 and found the POTS are actually 134-208 and a number 1377112. I found that the POTS are made by CTS, so after a couple trial and errors I found that I could drop in the resistant ring assembly from a new CTS Part #450GT25R254A2L .. https://www.amazon.com/gp/product/B01EJY35L8/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

I'm not going to go into detail about marking the wires, unsoldering old pots, bend 4 tabs out, carefully remove insides of POTS, move resistance ring and back plate to old housing and assemble with old shaft. I will warn you to bent the solder terminals toward the POT before installing or they will touch the chassis.

I hope this information was useful.

Tom

 

[BinaryMike]

Absolutely! It's always good to see repair techniques like this documented so other folks can benefit.

And welcome to AK!

 

[I LIKE MUSIC]

Nice work, thanks for sharing and for the pictures.

 

[tomdowns]

Absolutely! It's always good to see repair techniques like this documented so other folks can benefit.

And welcome to AK!

Thank you

 

[tomdowns]

Nice work, thanks for sharing and for the pictures.

Thank you

 

[AudioModern]

I just did this rebuild yesterday and it worked out great! My original gain pots were at 18 ohms and 120 ohms at max gain before (even with Deoxit F5 cleaning). Now they’re both at 0.25 ohms at max gain. Channel imbalance fixed!