NAD 3020 humming

[hostarn]

Hej good folks!

I've got a problem with my NAD 3020. It's humming, loud enough to be inacceptable. It does'nt seem to be affected by the volume, its always the same.
Now, should I change the capacitors near the power-supply (as I've seen some say often cause the humming in these type machines) or has THIS something to do with it (please look at the picture). These capacitors seems to have been really hot at one time or another as the plastic cover is pealing of like a beuty-cream at the end of a fashion-show brawl.

What do you think?

Thanks alot in advance for your thoughts!

Erik

 

[Juergen Knoop]

does it hum with inputs shorted?
regards

 

[hostarn]

idunno

Will check tomorrow, how do I go about that?

 

[Glowbug]

Use an RCA plug, connect the ground to the center pin.

 

[ostripper]

Total Recap man , all of them. 25 years old , heavily used.
OS

 

[hostarn]

Thank you guys.

Total? as in ... all of them? Well, why not then. It's not expensive right? And it's accessible soldering right? Should I buy the same amounts or could you recommend some mods? Another thread perhaps?

 

[taj]

Those 2 that are melted... use high temperature rated ones there, maybe higher voltage rated ones too.

"...pealing of like a beuty-cream at the end of a fashion-show brawl."

Haha. I didn't know they had fashion show brawls. Is that the latest reality TV trend? Is the runway shaped like an octagon with a fence around it?

..Todd

 

[ostripper]

for the 3020 , not many caps on the amps ( 1 - 1000u @ 6.3 2 - 1u @ ??? input caps and the 47u@ 25v bootstrap).

I only have the amp schema (attached), but I'm sure the supply caps are
small. For the best caps , 20- 30 USD would be max.

Also , regrease the 2n3055/2955 OP's , bd139's (Vbe/driver).

Go up in voltage to the next level (example 47u@25v < 47u @35/50v)
Input caps can be higher grade poly NP 1uf's
OS

 

[east electronics]

also you may try another source except your pc he he he he

you may also like to read this http://www.diyaudio.com/forums/showthread.php?s=&threadid=136261&highlight=

also your problem might be ""mechano""

meaning some contact is loose some ground is missing

regards sakis

 

[hostarn]

I changed those two caps that didn't look so good and now the amp is working like a charm.

Thanx alot airbody!