Morning all,

My trusty old NAD 3020a has stopped working properly. Prob somewhere
between vol control and preout/in. Suspect J111 muting FETs. I have a
reasonable copy of the cct diag, but cud really use a PCB layout to help
me finally fix this. Ill probably replace all those old drying caps
while Im at it.

Anyone ?

TIA

DH

David Harris wrote:

Morning all,

My trusty old NAD 3020a has stopped working properly. Prob somewhere
between vol control and preout/in. Suspect J111 muting FETs. I have a
reasonable copy of the cct diag, but cud really use a PCB layout to
help me finally fix this. Ill probably replace all those old drying
caps while Im at it.

Anyone ?

I got a diagram with my 302 when I bought at a modest cost, try asking NAD.

You may want to fix the RIAA correction while you are at it, NAD uses an
interpretation of the RIAA norm that leads to a 3 dB boost at 50 Hz, also
real high end stuff such as my old Audire preamp has had that aberration

DH

Kind regards

Peter Larsen

"David Harris"

My trusty old NAD 3020a has stopped working properly. Prob somewhere
between vol control and preout/in. Suspect J111 muting FETs.

** Suspect bad contacts on the pre / main links too.


I have a reasonable copy of the cct diag, but cud really use a PCB layout
to help me finally fix this.

** All you really need is a well trained nose for all the usual culprits
built into most cheaply made amps.

Cos NADs have every last damn one of them.


l probably replace all those old drying caps while Im at it.

** Make that a 100% certainty.

Got an ESR meter??

Be amazed how many small electros are totally stuffed.



..... Phil

On 13/04/2010 13:01, Phil Allison wrote:
"David Harris"

My trusty old NAD 3020a has stopped working properly. Prob somewhere
between vol control and preout/in. Suspect J111 muting FETs.

** Suspect bad contacts on the pre / main links too.


I have a reasonable copy of the cct diag, but cud really use a PCB layout
to help me finally fix this.

** All you really need is a well trained nose for all the usual culprits
built into most cheaply made amps.

Cos NADs have every last damn one of them.


l probably replace all those old drying caps while Im at it.

** Make that a 100% certainty.

Got an ESR meter??

Be amazed how many small electros are totally stuffed.



.... Phil



Thanks for all those pointers Phil, but it was actually a dry joint on
the cap (47u 63v) in the FET mute control circuit. It was causing mute
to be on permanently. I sussed it by judicious prodding But u are
right, and I am embarking on a cap swap out project over the next few weeks.

I still wouldnt mind a layout diag though if anyone has one ?

DH

"David Harris"


Thanks for all those pointers Phil, but it was actually a dry joint on the
cap (47u 63v) in the FET mute control circuit.


** Seen the same cap dry out and go open with similar results.

Then I found about 12 others well on the way.

Suggest you replace ALL the small electros.




...... Phil

David Harris said...


I still wouldnt mind a layout diag though if anyone has one ?

HiFi Engine has some for the 3020 and 3020i, may be similar?

http://www.hifiengine.com/manuals/nad/3020.shtml

--
Ken O'Meara
http://www.btinternet.com/~unsteadyken/

In article ,
Phil Allison wrote:
** All you really need is a well trained nose for all the usual
culprits built into most cheaply made amps.

Cos NADs have every last damn one of them.

I've got one in the kitchen - on most of the day - which must be pushing
20 years old. Not bad for a 'cheap amp' - given it sounds nice too.

--
*Never underestimate the power of stupid people in large groups.

Dave Plowman London SW
To e-mail, change noise into sound.