Distorsion sound when Powering On NAD 3020 ?

[liemjerry]

Hello

My NAD 3020 is rarely used.
Today I am powering on this NAD 3020 and found a while distortion sound from my speaker and then it dissapear, why this is happened ?

Thank you

 

[62vauxhall]

Those 3020's are known for bad/weak/failing solder connections. Can't say where your problem lay but I'd wager that the more closely you look at the board's solder connections, the more suspect one's you'll find.

 

[teal'c]

That and up to 40 year old parts.

 

[tube-a-lou]

Just be careful working on these guy's, check over thing's very carefully.

 

[TWTRTECH]

Most likely your power switch is going bad, has initial arcing when turning the unit on.

 

[Scott75s1974]

What's the sound like?

 

[liemjerry]

What's the sound like?

the sound like when we tune a radio station but has not reach the station..

 

[Scott75s1974]

Is the noise there even when there is no signal playing? If it's just static sound, then that would support the power switch arcing answer above.
Is it just in the first second of startup? Or does it last longer?

 

[liemjerry]

Is the noise there even when there is no signal playing? If it's just static sound, then that would support the power switch arcing answer above.
Is it just in the first second of startup? Or does it last longer?

The disturbing sound just appear in a few second after switching on the button, but about 10 seconds at least the sound disappear

 

[avionic]

The disturbing sound just appear in a few second after switching on the button, but about 10 seconds at least the sound disappear

Is this sound through the speakers or from the unit itself?

 

[liemjerry]

Is this sound through the speakers or from the unit itself?

the sound comes onto the speakers for a few seconds..but then disappear

 

[mbz]

A long shot would be bias not correct, check/set as per service manual. There are 3-4? versions of the NAD3020, with differeing main
filter cap placement and,,, need to get the correct sm/bias procedure.

 

[liemjerry]

A long shot would be bias not correct, check/set as per service manual. There are 3-4? versions of the NAD3020, with differeing main
filter cap placement and,,, need to get the correct sm/bias procedure.

I'd better send to service agent I recognize

 

[drumbum]

Caps charging?

 

[liemjerry]

Caps charging?

some cpas going to leak maybe?