Gents -

My 2245, which I thought was all back in perfect harmony, turns out to have the FM muting circuit on all the time, i.e. unlike the other uglier but more well-behaved 2220 I have lying around, you can't turn the mute off and get FM static and low-signal stations.

The switch would/should have been well De-oxit-ed during the last go round on the bench although I must admit I didn't pay particular attention to it as I hadn't noticed it was in-op.

Any known issues with this? Just wondering if there's some a common failure mode with the muting circuits before I go back in and re-attack the switch with more cleaner and start poring over the schematics for this unit yet once again...

TIA!

Clean it. If it still doesn't work pull it and test it. If it's broken replace it. Pretty straightforward.

Clean it. If it still doesn't work pull it and test it. If it's broken replace it. Pretty straightforward.

Um thanks. I already got my advanced degree in switch cleaning, diagnosis and replacement tho.

Question was not: "How do I fix a bad switch?"

Question was: "Do these (Marantz 22xx muting) circuits have any known failure modes other than the switch that I should know about ?"

I assume your answer to that question would be "Not that I know of" then?

Possibly one of the pots (the one on the rear panel or the one on the muting board) is dirty and the wiper is losing contact. There is a theory of operation write up in the service manual, check the Marantz database.

Tom

I assume your answer to that question would be "Not that I know of" then?

Your assumption is correct.

I didn't mean to come across as snarky, it just seemed quite cut and dry as to how you'd begin troubleshooting... the switch is the simple thing to check first and should take you no more than a couple of minutes to determine whether or not it is in fact the culprit. If you can rule it out then many people may jump in to help wade through the schematic and offer their diagnoses and suggestions.

Good luck, again my apologies I did not mean to offend.

Dave

Possibly one of the pots (the one on the rear panel or the one on the muting board) is dirty and the wiper is losing contact.

Thanks Tom - will have a look at those... an easy fix like that would be nice.

Good luck, again my apologies I did not mean to offend.

No problem, apologies as in retrospect I was a bit short in my reply as well. I hate those kinds of online forums where people jump down each others throats :bash:, don't mean to be that kind of online hardass curmudgeon (errr, I guess I want to be a real life face to face hardass curmudgeon?). :smilemad:

vibroverbus,
Have you taken the switch apart to clean ? Or does it have little holes you can spray into ? Sometime those push button swiches can be a BIG PITA to clean ....




Barney

vibroverbus,
Have you taken the switch apart to clean ? Or does it have little holes you can spray into ? Sometime those push button swiches can be a BIG PITA to clean

No, when I did the original service on this one I did non-disassembly spray cleaning to all the switches. I was more focused on other issues - massive hum from blown cap in pre-amp power supply, bad tape-mon switch causing one channel to be dead.

Certainly didn't give much extra attention to the muting switch. But looking back at it, the tape-mon switch caused last big problem so it very likely could be it's neighbor has the exact same issue. I think some others were sticky/intermittent too. This happens to be a family 'heirloom' piece from new and Dad used to be a big smoker back in the day, I've been suspecting smoke residue as a contributing factor to my switch problems here. That could also apply to pots as well, hence good idea to check those too...

Not looking forward to having to tear the whole thing back down again but I will if necessary... should be easy enough to test the continuity on the switch though and in addition to other tips, I might lift a lead to the muting switch just to ensure it's working properly before tearing down.