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#1
5 Style

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I have an old 70s era Marantz receiver that I've used for years. Works really well. Anyway, recently some of the inputs seem to be gunky and I have to reach behind the thing and jiggle the wires on some of 'em like the "aux" one that I have the CD/DVD player plugged into to get one of the channels to come on. When I do that the signal eventually will die off and I'll have to jiggle again. I don't think that the cord is the problem as I've switched the left/right channels of the cord and I still have a problem with the same input. I have been able to reach behind the thing and spray a bit of contact cleaner/degreaser spray on the offending contact, but that didn't seem to do much. I hate to have to pull the unit out because it involves unplugging everything, then not getting all of those wires lost behind some really heavy record cabinets that the whole thing sits on and... because I'm lazy. Still, it seems like this might be a necessary evil, because having one or the other stereo channel continually cut out is driving me nuts!

My question is this: once I've pulled out the receiver so that I can get better access to the back of it, what's the very best way to thoroughly clean off the RCA plug inputs? Just spraying that stuff on there didn't seem to work... Is there some sort of tool/method that I can use to clean the harder-to-get-to female part where the post part of the male input goes in (ignore the pornographic implications of what I've just described. :) )?

Thanx...
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#2
troutstudio

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I have an old 70s era Marantz receiver that I've used for years. Works really well. Anyway, recently some of the inputs seem to be gunky and I have to reach behind the thing and jiggle the wires on some of 'em like the "aux" one that I have the CD/DVD player plugged into to get one of the channels to come on. When I do that the signal eventually will die off and I'll have to jiggle again. I don't think that the cord is the problem as I've switched the left/right channels of the cord and I still have a problem with the same input. I have been able to reach behind the thing and spray a bit of contact cleaner/degreaser spray on the offending contact, but that didn't seem to do much. I hate to have to pull the unit out because it involves unplugging everything, then not getting all of those wires lost behind some really heavy record cabinets that the whole thing sits on and... because I'm lazy. Still, it seems like this might be a necessary evil, because having one or the other stereo channel continually cut out is driving me nuts!

My question is this: once I've pulled out the receiver so that I can get better access to the back of it, what's the very best way to thoroughly clean off the RCA plug inputs? Just spraying that stuff on there didn't seem to work... Is there some sort of tool/method that I can use to clean the harder-to-get-to female part where the post part of the male input goes in (ignore the pornographic implications of what I've just described. :) )?

Thanx...


I'd use a pipe cleaner and some Cramolin or similar
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#3
barryabko

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Signet makes a very good tool to clean RCA jacks:

Music Direct: My link

You can also use a Caig cleaner with the Signet tool if required.

Barry
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#4
BennyK

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I have an old Traynor Mono Bloc 300 watt power amp thats hissing and crackling pretty bad at the inputs too. Will try the suggested products. Thanks a lot. BK
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#5
chetatkinsdiet

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Gun cleaner. Go to just about any big box sporting goods store...Academy, d***s, etc....it will get the rust or gunk out. Deoxit is nice as well. Use that with proper qtips...not the ones from the grocery store though as they aren't packed as tight and might leave cotton in your jacks/inputs.

later,

m
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#6
Formula428

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QD Contact Cleaner. I believe it's mostly alcohol.
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#7
Steve L

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I hate to break it to you, but it may not be so simple as just spraying the connectors.

If it is just the connectors causing the issue, then cleaning the outside connector shell (ground) with some very fine emery cloth or similar and then using Caig or something similar can help. For the center pin you can use the Caig or similar as well. Many solvents could work, however you need to be careful they will not damage the plastic housings and inserts. The real good connector cleaning stuff is no longer available to the general public because of environmental laws. If it is possible, sometimes the center pin contacts can be squeezed together if they are now too far apart to make a good connection.

However, the typical problem with those RCA inputs is usually a cold solder joint or an oxidized wire wrap, depending on how the input jacks were wired. Repairing these would involve either re-applying solder to the RCA connector terminals on a printed circuit board or applying solder to the wire wrap.

If you tell me the model number of the receiver it may help since I could tell you how they were connected. Hopefully it is just a dirty connector.

Steve
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#8
jrfrond

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Spray an RCA plug with DeOxIt 5 and "exercise" the jack with it a few times. That should break up any oxides. There is a slim possibility it's a cold solder joint, but generally, receivers from that era, especially Marantz gear, were built like tanks, and soldering is generally NOT an issue.

When it comes to contact cleaners, there's a lot of useless crap on the market. The only one I've used since the early 80's is Caig DeOxIt 5 (formerly Cramolin R5). Everything else is a waste of money. Yes, a bold statement, but with lots of years using OTHER products to back up what I am saying. We also use a chemical called Stabilant, which is actually a conductivity restorer. We mix it with a little DeOxIt for a double-barrel punch.
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#9
eddiej

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I agree with JR, 70s era receivers (especially Marantz) rarely had cold solder joint issues. I also agree with Steve in that it might not be as simple as cleaning connectors.

You say the signal eventually dies off. Does it:
Cut out suddenly (which would indicate a bad connection), or
Loose some (but not all) the volume, which would indicate a resistance, capacitance or other internal issue?

I'm not sure how you feel about opening up the receiver cabinet. You could take a Volt-Ohm Meter (VOM) and verify (with the receiver unplugged) that the connections between the RCA jacks and the board they are connected to have good connectivity. You could also use the meter to confirm that the cables are not the issue.
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#10
Dave H.

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What JR said!

Dave H. :occasion5:
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#11
Resohead

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5, Let me play devil's advocate for a minute....
Are you sure it's the input connectors?
Is it only one source that drops out? (Phono, Tuner, Aux, Tape)? Or, does it happen to any of them?
Is it primarily at low volume levels?
Why am I asking this?

Is there a delay when you power on the system, then hear a click and the sound comes on?
That click is the protection relay. It disconnects the speakers from the power amp during turn on, till the amp settles down and no DC is present in the output.
It was very common for tarnish to build up on the relay contacts and cause audio to drop out or distort.
Next time it cuts out, raise the volume to punch through the tarnish layer and see if the audio comes back. (careful it can be loud). Or tap on the amp case to see if the audio comes back. Moving tha amp to fiddle with the cabling may have provided enough vibration to temporarily "fix" the problem.

The usual fix was to carefully open the relay housing and using a relay burnishing tool clean the relay contacts.

Shot in the dark.....
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#12
GeneZ

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My question is this: once I've pulled out the receiver so that I can get better access to the back of it, what's the very best way to thoroughly clean off the RCA plug inputs? Just spraying that stuff on there didn't seem to work... Is there some sort of tool/method that I can use to clean the harder-to-get-to female part where the post part of the male input goes in (ignore the pornographic implications of what I've just described. :) )?

Thanx...


On a unit that old you may have capacitors that are burned out.. They can cut on and off.. I had that happen with an amp I bought in the 80's. It would play for a while, then die out. Might be.
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#13
Sonorlite

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I'd definitely take a look at the solder joints - because if its a PITA to remove you not won't want to remove/rewire it again, if, cleaning the Phonos doesn't work. Kill two birds with one stone, as the old saying goes...
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#14
BeaTniK

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I would pull it out, take the lid off and clean it right myself.

http://www.audiokarm...ad.php?t=207005
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#15
Resohead

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Oh, one more thing.
Is there a PRE/MAIN switch on the rear panel?
They very often cause the same symptoms since the switch is usually never operated, oxidation builds up on the contacts interupting the signal between the pre and main amps.
Next time it cuts out, lightly wiggle the switch to see if it has any effect.
Spraying the switch out with contact cleaner and operating the switch a few dozen times will usually fix the intermittant audio problems.
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#16
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Thanx for all of the great advice. I think that I'm going to order some of that DeOxIt stuff as well as that RCA cleaner tool. I'll probably pull apart my amp to and do a bit of inspection/dusting as well. I don't imagine that it's all that dirty because just a few years back I had it serviced for some other stuff (I think I remember having a ground problem with the phono) and I know that the place I took it to popped it open and cleaned it out a bit.

It's a Marantz 2270 model receiver and it's done pretty well for me thus far. It does have that relay that clicks when it goes on, though I kinda doubt that this thing is causing any of the problems with it. I say that because the problem seems to be isolated to particular inputs. The aux input that my CD/DVD player goes into has an intermittent channel and for some reason it seems that neither channel in the tape input (that I was using to hook up my MP3 player too and worked fine for some time) works at all. The offending auxiliary jack will eventually work after jiggling the wire a bit. Hoping that I can just do a bit of cleaning of those inputs and be done with it... I really dread pulling everything apart though. I have to at least wait until I get that cleaning stuff delivered though so that buys me some procrastination time. Maybe by that time the thing will have fixed itself!

Pretty sure that there isn't one of these "pre/main" kinda switches on the back of the unit. I will check though.
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#17
GeneZ

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Thanx for all of the great advice. I think that I'm going to order some of that DeOxIt stuff as well as that RCA cleaner tool. I'll probably pull apart my amp to and do a bit of inspection/dusting as well. I don't imagine that it's all that dirty because just a few years back I had it serviced for some other stuff (I think I remember having a ground problem with the phono) and I know that the place I took it to popped it open and cleaned it out a bit.


Radio Shack sells a tiny kit. Its a rip off compared to here:


Big Size De Oxit
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#18
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Thanx for all of the great advice. I think that I'm going to order some of that DeOxIt stuff as well as that RCA cleaner tool. I'll probably pull apart my amp to and do a bit of inspection/dusting as well. I don't imagine that it's all that dirty because just a few years back I had it serviced for some other stuff (I think I remember having a ground problem with the phono) and I know that the place I took it to popped it open and cleaned it out a bit.


Radio Shack sells a tiny kit. Its a rip off compared to here:


Big Size De Oxit


Yeah, I think I'm going to order the cleaner stuff as well as the RCA tool from that Music Direct place. Radio Shack it seem is unlucky to have both of those things as nowadays they are pretty much a glorified cell phone seller. Not to mention the fact that they their prices probably are on the high side... I wonder how high though once the shipping is included on that online order...
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#19
GeneZ

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Thanx for all of the great advice. I think that I'm going to order some of that DeOxIt stuff as well as that RCA cleaner tool. I'll probably pull apart my amp to and do a bit of inspection/dusting as well. I don't imagine that it's all that dirty because just a few years back I had it serviced for some other stuff (I think I remember having a ground problem with the phono) and I know that the place I took it to popped it open and cleaned it out a bit.


Radio Shack sells a tiny kit. Its a rip off compared to here:


Big Size De Oxit


Yeah, I think I'm going to order the cleaner stuff as well as the RCA tool from that Music Direct place. Radio Shack it seem is unlucky to have both of those things as nowadays they are pretty much a glorified cell phone seller. Not to mention the fact that they their prices probably are on the high side... I wonder how high though once the shipping is included on that online order...


Not even close. What Radio Shack sells looks like a sample kit in comparison. I bought one because I did not know about Music Direct at that time. The RS kit sells for just as much as the big can, and the big can is much more. Use sparingly! Less is better with this stuff! Just enough to coat the parts. I have been using this for many years. Used to go under the name Cramolin. It was only for hi-tech applications at first. Always did cost more than the regular stuff. It can actually improve the connection, not just clean it. It can be used on new connections before they get dirty.
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#20
Velociamator

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Well, this is interesting. I am using a Marantz 2270 as my stereo "core" right now, because the Sansui 6600 is having the input issues. (Going to send it out soon). Anyway the 2270 has only two issues: the pushbuttons are a bit sticky, and it needs a lamp kit. But oh boy, can this puppy drive some speakers! Back when they were new, we had a 2245 in the living room. The 2270 is...better...and louder!
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