Frozen McIntosh MX135 😰

My MX135 froze  :(

All of a sudden I was unable to control the volume or change inputs.  At first, I'd turn it off and turn it back on with the red button and it would be good for a couple minutes.

Then, the red button would not turn off the unit, stopped so I turned it on and off with the black button.  That worked for awhile but not anymore.

Before I brought it to the shop, there were a bunch of @@@@@@@ on the screen.  Of course, the @@@@@@@ did not show up when I brought it in.

It has been in the shop for over a week.  The repair shop regularly repairs McIntosh but is stumped on this one.  He mentioned a system reboot, I think.  He's made calls into McIntosh.

Has anyone experience this problem and how was remedied?  I'd appreciate any input.
I owned an MX135 and periodically it would lock up and I was always able to resolve the issue. I would unplug the unit and while unplugged I would toggle every switch on and off. The I would turn each dial to full extreme, doing this drains all capacitance and allows the processors to return to default original settings. Once plugged back in everything worked as new. I had and MX134 and had the same results. 

Good luck
I have never had any problem with my MX135 which have been used for a few years in my second system. Usually Mcintosh gears are very liable devices.

In Amps or preamps and specially processors, turning on/off is not an efficient way to reset the device. Let your Mx135 unplugged overnight in order to discharge all capacitors and try again. Hopefully it will reboot the processor with its original version...
Former Authorized McIntosh tech, there is a service bulletin regarding the MX-135: locking up replace an IC in the front panel: IC20. Should be able to get the repair at your dealer.

Hope this helps
Thanks so much everybody!  Its the IC front panel and I'm going to get it back soon!


I'm having the same problem with My MX135
Did you get yours back? 
If yes may I asked, what did  it cost to Fix
Hi Everybody...

I was wondering if a copy of or the SB Number might be available. We do not have this information in the Database and our Service Department isn't able to provide one. Either eMail or scan or USPS would be greatly appreciated.

Mark - McIntosh Service Center
Fax - (952) 456-4937
eMail - McIntosh@AbSoundLabs.Com

I just got mine back from the shop with a new IC for the same reason. It worked for all of 3hrs 🤬

this is incredibly frustrating! It was in the shop for several months!