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2275 Intermittent left channel loss. new-to-me reciever

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dgatewood

New Member
I saved a 2275 from the neighbors trash and it works well but I'll randomly lose the left channel. I've had it apart 3 times, deoxit'd the pots, balance slider etc. Nothing too crazy. It'll work, but I don't know what makes the left come back on and why it goes out. I played it all day today without issue, then went outside and came back in... left is out again. There's no real pattern to it. It sounds awesome when it works. No distortion, crackling... smooth and sweet. So I know the channel isn't really blown out.

I've only been messing around with it for a few days and the only thing I've really done is dust it out with a compressor and deoxit the parts. I hosed it pretty good last night just to clean it better. I'm a computer tech and familiar with electronics but I'm totally unfamiliar with audio electronics.

Any thoughts? I see a rebuild kit is available for a little over $100 but I'm no exactly rich nor have much experience with audio rebuilds.
TIA
 

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Wow that was in your neighbors trash! You are very lucky and thanks for rescuing this great old Marantz.

Did you clean the push button switches, especially the tape monitor? Might be the contacts on the speaker relay need some burnishing with Emory paper. When the channel drops out tap on the relay and see if it comes back.

Again that is a great find. Look for the speakers and turntable next. :biggrin:
 
Fairlane said:
Wow that was in your neighbors trash! You are very lucky and thanks for rescuing this great old Marantz.

Did you clean the push button switches, especially the tape monitor? Might be the contacts on the speaker relay need some burnishing with Emory paper. When the channel drops out tap on the relay and see if it comes back.

Again that is a great find. Look for the speakers and turntable next. :biggrin:
Click to expand...

Yup. I was a more than a little surprised that it was going to be tossed. I even tried to talk the guy out of it but he didn't care. *shrug* I'm far from an audiophile but even I know the name Marantz. What I wasn't prepared for was the weight of this thing. Man. My back hated me.

So, I did spray and clean everything I could see, reach, get to. The knobs, buttons and balance slider all are smooth as butter with no crackles or noise. I thought I got everything pretty well. To be fair, it was in pretty good shape when I got it, so I can't take a lot of credit. I disassembled everything that I felt comfortable with. Used about a half a can of Deoxit on it, in all.

**Edit** So I'm clear, the relay that you're talking about is the "protection relay" on the power supply board? I don't remember seeing any other relay's in there.
I think I'm mistaken about that relay. I'll try to find what you're talking about.

I was a little concerned about poking around in there with those monster caps while it was on. I'm pretty unfamiliar with this high power stuff. Computers are not really that dangerous.
 
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Probably dirty controls or a bad solder connection, google dry solder joints for pix.

The marantz gurus have probably seen this before with this model. In the meantime
use RCA cables connected from Left Pre-Out to Right Main-IN and from Right pre-out
to Left main-in, ie, cross them. If problem stays on the left channel then it's a power amp
issue. Problem is intermittent so may need to wait a while.
 
mbz said:
Probably dirty controls or a bad solder connection, google dry solder joints for pix.

The marantz gurus have probably seen this before with this model. In the meantime
use RCA cables connected from Left Pre-Out to Right Main-IN and from Right pre-out
to Left main-in, ie, cross them. If problem stays on the left channel then it's a power amp
issue. Problem is intermittent so may need to wait a while.
Click to expand...

Ok I’ll try that today then look around for some bad joints. Is there a specific board/spot I should focus on? I have a smd rework station, so I could hit it with some hot air if you think that might help to reflow the board.
 
Find out first if it’s preamp or amp. That gives a direction to look. And you had it right on the relay. Clear plastic box on power supply board. The signal to both amps goes through that relay, so bad contacts can make one channel go out. Tapping on it when a channel is out might bring the channel back if relay is the problem.
 
Steven Tate said:
Find out first if it’s preamp or amp. That gives a direction to look. And you had it right on the relay. Clear plastic box on power supply board. The signal to both amps goes through that relay, so bad contacts can make one channel go out. Tapping on it when a channel is out might bring the channel back if relay is the problem.
Click to expand...

Ok. Gotcha. I’ll look at it later and report back. I’ve noticed that on my moms Onkyo she has jumpers on the back. I’ve read other posts about jumpers. Am I supposed to have jumpers acrossed those pre/main rca’s?

Sorry I’m such a lamer with this stuff. It’s a totally new area for me. Thanks for y’all’s patience.
 
I put the rca cables on as instructed and both channels came on but reversed. RL LR

I jumped them over RR LL and both channels work.

Am I supposed to have the pre amp and main amp jumpers like my moms old Onkyo? There were no jumpers on this and looks like there never were by the patina.
 
I found a post regarding the jumpers where it says the 2275 has internal RCA jumper contacts. Could it be that one of those contacts is just dirty? I did get it to work if I jumped them with cables. It’s a PITA to get it out of the wood case and apart to clean contacts if a pair of jumpers will get me working again. Then I can push that job off till the day I re-cap it.

Could it be that simple or am I deluding myself? I don’t want to ruin it.
 
The 2275 has internal jumpers that disconnect when you insert RCA’s. If it works with cables inserted, those internal contacts might be the culprit. I had that problem on a 2325. You can Deoxit the jacks from inside the case and likely eliminate those as a possible source. When you Deoxit them, insert and remove some cables 15-20 times while you Deoxit. That should clean the contacts pretty well.
 
Sprayed Deoxit into the main and pre jacks. Gave it a dose of ye olde in-out, in-out routine and now it works again.

I guess those were the issue. I can tell that the left channel is a little lower than the right so I guess I’ll have to recap it sometime soon.

But, I’m jammin again.... for now ;)

Is it better to go with something like this... or piece all the parts together from scratch?
https://irebuildmarantz.com/catalog/index.php?cPath=1
 
If you plan to do several units, it’s slightly more economical to buy the parts. But it takes time to research what you need and you never get everything. For a one-off restoration, I highly recommend Randy at Irebuildmarantz.com. His kits are complete and the parts are high quality. Also, if you have questions, Randy is always willing to help.
Steve
 
That sounds perfect! I only have the one unit so buying extras doesn’t make sense for me. I can really see this being a gateway drug to other audio stuff but for now I’m super happy with this one! I built some ghetto speakers from scrap wood and free-to-me speakers.

They have a 28in port length inside *based on no math or understanding* but they do sound really nice.
 

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Thank you!
I appreciate all of the help.
Those are Cerwin Vega car speakers lol. They’re plenty loud enough for me and have shockingly good bass response in those little box’s.
 
I hate to admit my age, but I built a pair of small plywood bookshelf speakers using 5” car speakers when I was a teen - about 50 years ago. For what they were, they had astounding bass. I’m sure yours sound great, also.:thumbsup:
 
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