NAD 3020 humming

hostarn · 26th August 2009, 08:31 PM

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 · 26th August 2009, 10:19 PM

does it hum with inputs shorted?
regards

hostarn · 27th August 2009, 01:22 AM

idunno

Will check tomorrow, how do I go about that?

Glowbug · 27th August 2009, 01:29 AM

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

ostripper · 27th August 2009, 01:33 AM

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

hostarn · 27th August 2009, 03:48 AM

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 · 27th August 2009, 04:51 AM

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 · 27th August 2009, 05:04 AM

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

sakis · 27th August 2009, 05:37 AM

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

you may also like to read this vintage amplifier repair/upgrade manual

also your problem might be ""mechano""

meaning some contact is loose some ground is missing

regards sakis

hostarn · 28th August 2009, 09:38 PM

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

Thanx alot airbody!

27th August 2009, 01:29 AM	#4
Glowbug diyAudio Member Join Date: Feb 2006 Location: Hillsborough, NC/McLean, VA	Use an RCA plug, connect the ground to the center pin. __________________ Jim J.

27th August 2009, 05:37 AM	#9
sakis diyAudio Member Join Date: Jan 2006 Location: nea makri athens greece	also you may try another source except your pc he he he he you may also like to read this vintage amplifier repair/upgrade manual also your problem might be ""mechano"" meaning some contact is loose some ground is missing regards sakis __________________ SERVICE ΕΝΙΣΧΥΤΩΝ ΚΑΙ ΙΑΠΩΝΙΚΩΝ ΜΗΧΑΝΗΜΑΤΩΝ ΗΧΟΥ www.eastelectronics.gr

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26th August 2009, 10:19 PM	#2
Juergen Knoop diyAudio Member Join Date: Jan 2007 Blog Entries: 3	does it hum with inputs shorted? regards

27th August 2009, 01:22 AM	#3
hostarn diyAudio Member Join Date: May 2009	idunno Will check tomorrow, how do I go about that?

27th August 2009, 01:33 AM	#5
ostripper diyAudio Member Join Date: May 2008 Location: Albany , NY (smallbany)	Total Recap man , all of them. 25 years old , heavily used. OS

27th August 2009, 03:48 AM	#6
hostarn diyAudio Member Join Date: May 2009	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?

27th August 2009, 04:51 AM	#7
taj diyAudio Member Join Date: Feb 2005	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

28th August 2009, 09:38 PM	#10
hostarn diyAudio Member Join Date: May 2009	I changed those two caps that didn't look so good and now the amp is working like a charm. Thanx alot airbody!