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Help - MC 2105 suddenly no sound

doji

doji

New Member
Help needed.

My MC2105 suddenly lost its sound. I tried clean up the pots, and then still the same. I plugged in the headphone, I can hear sound on left ear pretty clear and strong, but the right ear sound is very weak.

The meter's needles don't move at all.

I swapped out the MC2105 , hooked up another power amp, everything is normal and good. So pretty sure the Mcintosh is the root cause.

BTW, just let me know, to clean the pot, can I spary DeoxIT from the front panel to the pot's pole? Or I have to take the bottom off to spray on the pot's body from there?
Help and advice please.
 
Last edited:
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Do not use the red can D5 in a potentiometer.......use green can fader lube.

You can use the D5 on the back switch and the speaker switch.

You will need to remove the bottom.
 
c_dk said:
Do not use the red can D5 in a potentiometer.......use green can fader lube.

You can use the D5 on the back switch and the speaker switch.

You will need to remove the bottom.
Click to expand...
Thanks.

What's the difference between these two?
 
Faderlube has lubricate as a major part of its solution. D5 has little. The Caig website explains.
 
Hello

No sound on MC2105 can't be a question of dirty pot .
I will suspect the speaker on / off switch going bad with the time . Some fail in on position ( which is not a problem ) and some fail in off position (that's seem to be the case ) and whatever your turn the switch the contact do not change anymore . In this case only one solution : replace by a new switch (double contact switch).

but the right ear sound is very weak. That is possible in this case to be a question of bad contact (as previous said , clean the rear switch )
 
clinic-audio said:
Hello

No sound on MC2105 can't be a question of dirty pot .
I will suspect the speaker on / off switch going bad with the time . Some fail in on position ( which is not a problem ) and some fail in off position (that's seem to be the case ) and whatever your turn the switch the contact do not change anymore . In this case only one solution : replace by a new switch (double contact switch).

but the right ear sound is very weak. That is possible in this case to be a question of bad contact (as previous said , clean the rear switch )
Click to expand...
I hope the speaker on/off switch is not totally dead :) But coincidentally, the amp lost his sound after my friend's 1 year old played with this switch (when the amp was power off, then afternoon my wife turned on for music but none came out so she reported the issue).

I will take it out and remove the bottom and try to spray cleaner one more time to give a try.
 
Did you put the 2105 back in after switching it out? If still not working, consider that my 2105 speaker connections are finicky, and if I'm connected to the 4 ohm taps, the 8 ohm taps can't be screwed all the way in or the channel is weak, or I lose it. I don't know why but by keeping it unscrewed it's fine. Also, I use bare wire so I have to be very careful that strands from one channel aren't touching the other channel, or that can affect output as well.

I would confirm that everything in back is connected properly, and see what happens when you jiggle the speaker wires a little after they are connected.
 
sberger said:
Did you put the 2105 back in after switching it out? If still not working, consider that my 2105 speaker connections are finicky, and if I'm connected to the 4 ohm taps, the 8 ohm taps can't be screwed all the way in or the channel is weak, or I lose it. I don't know why but by keeping it unscrewed it's fine. Also, I use bare wire so I have to be very careful that strands from one channel aren't touching the other channel, or that can affect output as well.

I would confirm that everything in back is connected properly, and see what happens when you jiggle the speaker wires a little after they are connected.
Click to expand...

Sounds like in your case at some time in the past someone put too long of screws in your 8 ohm taps.
 
Here are some updates:
1. I did open the amp's bottom, and spray DeoxIT on to the speaker on/off switch.
2. Then after a few exercise with the switch, it got even more stiffer, and I think it's now totally stuck at some position which is not the ON.
3. Plug the amp back in, while power on, I see the meters jump. But still no speaker output, and the headphone output stays the same (left is kind of OK, right is very weak).

Without further diagnosis, the issue seems with the Speaker On/Off switch, which the DeoxIT didn't rejuvenate it at all. I need order a part of that switch, any suggestions other than Ebay?
 
clinic-audio said:
Watch my message
this switch is no longer available
Click to expand...

Wonder if I can totally bypass this Speaker On/Off switch, and set it as 'ON' permanently. I see there are 4 pins have wires, I guess each channel has a pair, maybe add a jumper wire to connect each channel's two pins will make the bypass working.

Now the question - which pin to which pin to wire together?
 
Before to make such "modification" check with your ohm meter that the switch is bad .
You can do it in power off of course , after I will give you the right colors
 
clinic-audio said:
Before to make such "modification" check with your ohm meter that the switch is bad .
You can do it in power off of course , after I will give you the right colors
Click to expand...

Yeah the switch is proved dead. I put it at ON position, but the meter shows no reading as it's broken.
 
If I good remember there is one brown wire and one white wire
For the other chanel this is white/brown and the other wire white with brown dot
Can you post a closer picture to confirm colors in your amplifier ?

here is a picture made 2 years ago regarding one MC2105 dead switch modified with yellow strap

MC2105-speaker-switch.JPG
 
clinic-audio said:
If I good remember there is one brown wire and one white wire
For the other chanel this is white/brown and the other wire white with brown dot
Can you post a closer picture to confirm colors in your amplifier ?

here is a picture made 2 years ago regarding one MC2105 dead switch modified with yellow strap

View attachment 1613760
Click to expand...

Thank you for the picture. Looks like the Yellow wire connecting two pins in each vertical side of the switch. Now I've got the idea.
 
is it possible to open the bad switch, fix and restore it back to functioning ? I will try this extra mile of run with my loved MC2105..
 
Are replacement switches still available from McIntosh? If not, is there a drop in aftermarket part available? Or is this type of switch unobtainium?
 
I took one apart one time....if I remember correctly there is a plastic teeter totter like part that breaks rendering it unrepairable.

You will have to either jumper it or create your own repacement. I jumpered it.
 
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