Marantz 1122DC lost channel - Intermittent

[labatt242]

Hello!

I have a friend having a Marantz 1122dc which lost a channel sometimes. Once we touch the "Tone Defeat" and "Loudness" buttons, the channel is working again but it can take several minutes to make it working. The power amp section has been restored (new transistors, new pre drivers and drivers transistors, new caps, checked for cold solder joint, BIAS OK and DC OK. Seems like he doesn't have the issue when he plug a headphone. I am about to take a look to :

- Both Tone Defeat and Loudness buttons to be desoldered and cleaned or replace them with a sub part (if possible). It is possible to clean this kind of button?

- Check the pre-amp board to be recaped

I would like to know if there is something else I can check before to go with these fixes.

Thanks!

Guy

 

[mbz]

No knowledge of the 1122dc, currently working on a Yamaha CA-1000, amp was working ok but not sounding great.
The magic spray may get it working but the chances are the switches need to be stripped down and cleaned.
Before pic. This switch is not too bad

 

[dr*audio]

Clean all the controls. Check the speaker relay by tapping on it with a non metallic probe like a plastic pen. If the sound cuts out or returns, replace the relay.

 

[labatt242]

Clean all the controls. Check the speaker relay by tapping on it with a non metallic probe like a plastic pen. If the sound cuts out or returns, replace the relay.

I forgot to say the relay has been replaced also in the past (bad channel issue). I will take a look of all the control. I will remove the faceplate and the pre-amp board to do a good job cleaning.

 

[labatt242]

No knowledge of the 1122dc, currently working on a Yamaha CA-1000, amp was working ok but not sounding great.
The magic spray may get it working but the chances are the switches need to be stripped down and cleaned.
Before pic. This switch is not too bad
View attachment 1431448

I will check the switches and use Deoxit D5 to clean it up!

 

[Oerets]

The two switches you mentioned may need to be dissembled to clean effectively. Not an easy job for the novices. Requires removal of the panel and freeing board up.
Look at the top of the switches for tiny holes. If seeing them carefully spray and work cleaner into the switch at this time.
If no holes then carefully removal of spring retainer to remove the shaft.
You may get lucky and be able to spray into the switch enough without removing the shaft completely. There are springs and contacts on the shaft to keep an eye on them, so be very mindful of parts.
Also clean the mode switch when a problem with a channel occurs. Another hard one to get at.

 

[labatt242]

The two switches you mentioned may need to be dissembled to clean effectively. Not an easy job for the novices. Requires removal of the panel and freeing board up.
Look at the top of the switches for tiny holes. If seeing them carefully spray and work cleaner into the switch at this time.
If no holes then carefully removal of spring retainer to remove the shaft.
You may get lucky and be able to spray into the switch enough without removing the shaft completely. There are springs and contacts on the shaft to keep an eye on so be very mindful of parts.
Also clean the mode switch when a problem with a channel occurs. Another hard one to get at.

Thank you so much for this information. I will try the easier way to clean the switches. If not possible, I will be patient to disassemble both switches and clean it up.!

 

[labatt242]

Hi there,

Here a little update regarding this issue. I successfully disassembled and cleaned all the switches. I can say it's not an easy job. Here some pictures.

No more scratchy sound now!

Thanks for the help!

Guy

 

[Oldsansui441]

Good to hear you have her working nicely now, great work .

 

[Deerwood]

I have a Marantz 1122DC that I'm working on for a friend. Volume control was scratchy when turning. After I cleaned all the controls I noticed the left channel wasn't playing? Anything I can check to try and get it to work again? Doesn't seem to be an easy place to clean or? Thanks! ; )

 

[Oerets]

Was it working before?
Also what did you use for cleaner on the sliders?
Fader Lube I hope.

 

[Deerwood]

Was it working before?
Also what did you use for cleaner on the sliders?
Fader Lube I hope.

Don't know for sure about the Left channel working, waiting to hear back from the owner? I used Deoxit cleaner and Deoxit Gold on the Pots/knobs. I used nothing yet on the slider-s. That's hard to get at. I fixed the scratchy knobs but noticed the left channel not working when I tested it. IDK? ; )

 

[Oerets]

That has the preamp to main amp connections on back. With a pair of patch cords swap the channels and see if it moves or starts working.

Also on some models in that series the board connections from the mode switch will have cold solder joints. With a chop stick tap around the board and see if it will bring it back. Test the volume and all of the controls on the board at this time.

 

[Deerwood]

That has the preamp to main amp connections on back. With a pair of patch cords swap the channels and see if it moves or starts working.

Also on some models in that series the board connections from the mode switch will have cold solder joints. With a chop stick tap around the board and see if it will bring it back. Test the volume and all of the controls on the board at this time.

Not being familiar with this Amp, the owner called me and said to be sure it was set on stereo. Lol Otherwise it will play only one channel at a time! Problem solved! Thanks for replying! Yikes! ; )