McIntosh C2200 Very Low Volume

ossidian

Active Member
Was hoping someone on this forum could comment on an issue I have been having with my C2200.
I turned on the preamp a few days ago and there is very little sound (maybe 1%) coming thru speakers. Full volume on preamp results in barely audible volume.
Have verified amp/amps are performing fine. The symptom reminds me of the days when my little brother would accidentally press the tape output loop switch, similar sound.
Same issue thru the headphone jack. Volume on left channel noticeably stronger as well.

I have performed restart of unit and reset of unit. All tubes changed this week. All connections checked.
All switches light up and "seem" to be working correctly. Spoke to McIntosh service (very generous with his time) and he was also unaware of such issue.

This issue first presented itself about 5 months ago and was resolved a day later when unit was turned on and inexplicably starting working correctly.

Any help appreciated. Thank You.
 
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Bad ground? Perhaps something in your home is plugged into the same circuit and it's causing some noise. Happened to me.
 
Hold the standby button for a minute and the unit will reset .
Thank you, Have done the reset, the standby button reset is for the C2300. The C2200 works by holding down the "mono" and "output 2".
Also performed the Reset of Microprocessors by turning off the power switch and waiting for 2 minutes and then press the standby.
Both have yielded no results unfortunately.
 
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The muting circuit for the c2200 is a derivative of the input switching scheme that Mac introduced with the C33 and has been using it now for decades for input switching before the C37 went to relays and as a muting circuit now for over 30 years.

First bit me with a extremely intermittant MX117 that kept losing one channel and inspite of spending multiple weeks, multiple times running on the sales floor for hours NEVER lost a channel in my presence but would inevitably fail the night the owner brought it home.

Have your local experienced tech, these are I believe double sided boards, replace the muting driver pnp transistor.....if you are really superstitious have the muting JFETs replaced also.

I doubt if it will ever fail for your tech.......back in the 80s it was Larry Fish that told me to shotgun the MX117 repair, sometimes you have to do what you have to do.
 
The muting circuit for the c2200 is a derivative of the input switching scheme that Mac introduced with the C33 and has been using it now for decades for input switching before the C37 went to relays and as a muting circuit now for over 30 years.

First bit me with a extremely intermittant MX117 that kept losing one channel and inspite of spending multiple weeks, multiple times running on the sales floor for hours NEVER lost a channel in my presence but would inevitably fail the night the owner brought it home.

Have your local experienced tech, these are I believe double sided boards, replace the muting driver pnp transistor.....if you are really superstitious have the muting JFETs replaced also.

I doubt if it will ever fail for your tech.......back in the 80s it was Larry Fish that told me to shotgun the MX117 repair, sometimes you have to do what you have to do.

Thank You! This is why I continue to come to this community, such a wealth of information. I will follow your valuable advise, again thank you.
 
If you are lucky it will fail for your tech, but the way Murphy gets involved with these thing most likely will never fail while it is near the bench.

According to my client back in the 80s just calling me on the phone would cause the channel to come back on......darn thing was scared of me I guess......
 
If you are lucky it will fail for your tech, but the way Murphy gets involved with these thing most likely will never fail while it is near the bench.

According to my client back in the 80s just calling me on the phone would cause the channel to come back on......darn thing was scared of me I guess......

c_dk was spot on with the diagnosis. Replacing the muting pnp transistor was indeed the correct solution for fixing the C-2200. I also had tech replace both pnp jfets for peace of mind.
 
Any time you are dealing doped silicon crystal, charge carriers and quantum physics being on the positive side of the "blind" squirrel concept is always a good thing.
 
On a side note the display screen went dead a while back on the C-2200. I was about to order a new display when the tech noticed a bad resistor. The replaced resistor restored my display screen.
 
Just picked up the C-2200 yesterday afternoon, sounds fantastic and looks fantastic. Randy at Audio Technician not only got it sounding great but looking great as well, he even cleaned the gold knobs via ultrasonic.
Now that's service. Well worth the wait.
 
Is this a common issue with the 2200? Is it easy to find a Tech to work on the newer Mac's?
 
Is this a common issue with the 2200? Is it easy to find a Tech to work on the newer Mac's?

From my sources and technicians I have spoken to it's certainly not uncommon for the muting fets and driver transistor to fail. My understanding the muting issue has been addressed and corrected in the newer units.
 
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