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Marantz Model 1200 Left Channel Issue

MarantzRefrb said:
In my experience, calling people laymen without giving them the benefit to experience, or learn something, will keep them in that spot you call, 'laymen'.
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To me, 'layman' is not an insult. It only describes someone with perhaps an interest, usually an interest that lasts as long as getting their item fixed, but who isn't an expert and/or doesn't do it for a living.
People learning new skills is good thing. Folks like Tom and myself won't be around forever. However, someone with very little to no experience can make problems much, much worse by being given bad advice, or even misinterpreting good advice.
 
MarantzRefrb said:
Alright, do you have any actual helpful info for our OP, or are you here to assert your wisdom?
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Tom covered the first step in post #2. If you would like help with the issue with your 1200, I would recommend starting your own thread. Keeps things a little more tidy and less confusing that way.
 
MarantzRefrb said:
And what was your recommendation?
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The number one cause of problems that I see with vintage equipment across all brands is connection issues. Cracked solder joints, loose/corroded/broken ground connections, dirty/corroded switches and/or potentiometers, dirty/corroded/pitted relay contacts, and even broken wires on units that have been previously worked on. Diligently eliminating those sorts of things should always be done before beginning any kind of refurbishment/re-cap/restoration. Believe me me, it will add years to your life.
 
Did you not read the first post? Our OP has replaced all the caps in this 1200 in 2011, and only now does this unit have problems. Don't you think he already did check the controls by this point?

This is not his first day here.

lo-d dad said:
Hello AK, I recapped my Model 1200 in 2011 thanks to all the help from various members. I still love the sound and look of the model, but for a while I have been noticing the left channel is quieter than the right channel, especially right after I power on. If I keep using it, the left channel is back to about the same level as the right channel eventually. When the left channel is quieter, the sound is also distorted a little as well. If you have any suggestions what I should check, please let me know. Or, if there are any similar discussions somewhere, please also let me know. I still don't have much experiences working on old electronics products, but I surely enjoy it. Thank you in advance,
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Replacing all of the caps typically fixes nothing, except by pure luck. I have fixed plenty of re-capped and "restored" receivers that were still chock full of the issues noted in post #27. Some were even caused by being re-capped or "restored".
 
Replacing all of the caps, generally ensures another 45+ years of life for the unit, and saves on worrying about dried up electrolytic's. It usually fixes the sound too, which is what I'm more concerned with.

I'm here to try to help the OP, if I can.
 
MarantzRefrb said:
Replacing all of the caps, generally ensures another 45+ years of life for the unit, and saves on worrying about dried up electrolytic's. It usually fixes the sound too, which is what I'm more concerned with.

I'm here to try to help the OP, if I can.
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Not sure why I bother...
 
It's been well established here, that recapping an entire unit does not fix a blown Left channel, or some random problem, though it can sometimes. Repair the problem first, then recap.

Changing all the caps, is like changing the oil, why not replace out of spec components, before they ruin an irreplaceable part?

I wouldn't buy a classic car, and insist on using the stock oil, or bias-ply tires from the 60's.
 
How you came to conflate my admonishment of twiddling pots with not re-capping old gear, I don't know.
I'm trying to get people to be methodical in their approach to repairing equipment, to start at the beginning. To check the likely things first, and to not waste time chasing zebras when the problem is probably horses.
 
tarior said:
The number one cause of problems that I see with vintage equipment across all brands is connection issues. Cracked solder joints, loose/corroded/broken ground connections, dirty/corroded switches and/or potentiometers, dirty/corroded/pitted relay contacts, and even broken wires on units that have been previously worked on. Diligently eliminating those sorts of things should always be done before beginning any kind of refurbishment/re-cap/restoration. Believe me me, it will add years to your life.
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He recapped this in 2011 - not sure where you got the idea that I was suggesting this current problem he's experiencing, has anything to do with caps at all.

I asked if DC balance/offset and Bias were in spec, and then you took us on this detour, suggesting I'm being reckless by recommending what the SM suggests.
 
Thanks, lo-d dad! I did not check every cap on the board before replacing all of them. Of the three caps that were on my A8 relay board, all of them were badly out of spec, that made me want to replace every cap, and so I did.

I have replacement transistors on order, should be here tomorrow. Hopefully that will be the last problem on my 1200.

Did you Deoxit, and exercise all of your knobs and controls, to see if that was the problem with yours?
 
MarantzRefrb said:
Thanks, lo-d dad! I did not check every cap on the board before replacing all of them. Of the three caps that were on my A8 relay board, all of them were badly out of spec, that made me want to replace every cap, and so I did.

I have replacement transistors on order, should be here tomorrow. Hopefully that will be the last problem on my 1200.

Did you Deoxit, and exercise all of your knobs and controls, to see if that was the problem with yours?
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Yeah, I cleaned all the switches and controls. It seems working better. I will see how the amp works when it's cold. By the way, how do you find faulty resistors and transistors?
 
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