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First time Vintage receiver and speakers owner dealing with humming

coonmanx said:
Exactly. And while I don't really believe in "shotgunning" anything replacing the filter caps can be cheap and easy if you know what you are doing. Me. I dabble in soldering and desoldering. Definitely not a pro at it. But I think I could handle replacing two caps. I hope so anyway... But I have not tried that yet. First project for me is to put a Technics SU-V707 back together again and see if it works...
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These caps are usually electrolytic and bad ones may be spotted by a leaky film on the mounting surface of the cap, or a bulged in the cap body, or other things.....
 
WaynerN said:
These caps are usually electrolytic and bad ones may be spotted by a leaky film on the mounting surface of the cap, or a bulged in the cap body, or other things.....
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Can caps be checked in circuit or does it require lifting one leg? I can't remember...
 
WaynerN said:
Capacitors in the power supply are probably the culprit. They filter the pulsating DC into pure line DC. If they fail (due to age or other) they will drag along 60hz hum which will go thru the entire system, be present on all inputs and no amount of grounding will solve it.
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And no filter cap will solve a ground problem. As I said earlier, it is likely a ground or power supply problem. He does not have the ability to replace the filter caps, so I was trying to eliminate ground problems.

Done. Let the shotgunning proceed.
 
I'm still going with a regulator.

If the hum increases with the volume control, then it is introduced before the amp section.

Could be rectifier or regulator on the power supply.

Two repairs I have done recently had hums. On one it was a regulator, and the other was a cap on the power supply.

How about a pic of the guts?

Rob
 
Borrow a different receiver and see if the problem goes away. If it does, it is not your envioronment. Probaby cheaper and better to replace than repair that receiver.
 
spark1 said:
How are you planning to "check" them? If you go to the trouble to test them, just replace them.
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I don't know. That is why I am asking. Don't people just measure them to see if they are still in spec? Me, I would probably just replace them.
 
Measurement really requires ability to measure capacitance, ESR and leakage (electrical).
 
Sometimes even properly rebuilt stuff hums. Ground loops can be a bitch to pin down.

Go to Guitar Center and buy a “Hum X”. Should be less than 50 bucks. Plug that into the wall and your amp into that. I have a couple on hand just in case.

Good luck, and Have Fun! Mark
 
I have two early 70s receivers I have recently acquired, a Sony str-6046a and a KLH model 52. They were purchased on line, unserviced.

Much to my surprise, BOTH produce a tingling sensation on the faceplate when plugged in; and on the KKH, also through the knobs.

I saw a previous comment mention the s as a symptom -- does this indicate a grounding problem, leaking caps (like a bad "death cap" I recently learned about), or something else possibly?

Thanks!
-N.
 
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