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NAD C320 on the blink.

R

rob

Jan 1, 1970
0
Hi all

I have a problem with a NAD C320 amp and wondered if anybody could
offer any thoughts on what has happened and how I might fix the problem.

The amp is hooked up to a computer (headphone output -> standard
leads). On power-up, the computer emits quite a deep and sustained
sound (it's an Apple Mac).

Usually I power the amp down for the night but in this case the amp was
left on all night. When I started up the mac in the morning, I heard
the startup sound, but that was the last I heard from the amp.

Now the TAPE 1 MONITOR led, which is usually green, is amber, and the
selector button below it toggles bright <-> dim amber.

No sound at all. Not a peep!

I've posted on one or two other newsgroups but it seems that I may have
posted in the wrong place as they appear (quite rightly ... I'm not
criticising them!) more interested in discussing new gear, etc.

NAD themselves suggest that the issue is in the selector circuit but
want me to ship them the unit and pay them to fix it. It's way out of
warranty and is in excellent condition (yes, apart from this problem!)
so I'm very keen to get it fixed and avoid the same issue in the future.

I found a posting on USENET from way back that suggests the
soft-clipping circuit may have suffered. I don't know.

Can anybody assist?

Thank you

Robin
 
M

Mark D. Zacharias

Jan 1, 1970
0
The model 302 has this problem resulting from a bad resistor. Could your
"320" be a typo?

Mark Z.
 
B

b

Jan 1, 1970
0
Not familiar with this unit, sounds like it is in protection mode
probably due to a shorted transistor. have you measure the voltages on
the output stage regulators or transistors ? Output protection
devices? if the speaker terminals have DC on them the amp will
doubtless not fire up to avoid further damage.
just a few ideas
Ben
 
R

rob

Jan 1, 1970
0
The model 302 has this problem resulting from a bad resistor. Could your
"320" be a typo?

Mark Z.

Hi Mark

Nope, it's a C320 (looking at it now).

Sounds like the bad resistor could be an issue.

Thanks for the reply!

Robin
 
R

rob

Jan 1, 1970
0
Not familiar with this unit, sounds like it is in protection mode
probably due to a shorted transistor. have you measure the voltages on
the output stage regulators or transistors ? Output protection
devices? if the speaker terminals have DC on them the amp will
doubtless not fire up to avoid further damage.
just a few ideas
Ben

Thanks Ben for your ideas.

I'm interested in protection mode -- how can one tell if this is
actually the case.

No I have not measured any voltages (no meter!) but I intend to
appropriate some equipment and do just that.

Regards

Robin
 
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