NAD 304 amp died, what next?

[Derek]

Hi,

I have an NAD 304 integrated amplifier. About a year ago it stopped
working and I brought it into a local shop which repaired it for a sum
that was about 2/3 the cost of picking up a used one. Now the amp has
stopped working again. This is a bedroom amp and doesn't really get
any abuse. I'd really like to get this working again without shelling
out so much money. Buying a new replacement is kinda out of the
question just cause money is tight right now.

I'm sort of toying with the idea of working on it myself, but I've
never worked on audio components and am not well versed in opamps,
transistors capacitors and such. That said I am quite mechanically
inclined and am often tearing apart computers, or working on my car.

So the questions are:

Is it worth trying to fix in the first place?

Are there any good books or internet resources that would cover repair
of hi-fi audio equipment?

Am I likely out of my gourd considering I never took any EE classes in
college?

Does anyone know of a reputable place near Redondo Beach California
that I could bring the amp to for repair?

Thanks, Derek

[Tim Schwartz]

Derek,
The first thing I'd do is call the shop that worked on it last to see
if they will cover it. If its been under a year, and the unit is in
good condition, they might have enough pride in their work to at least
give you a break in price. If your looking for another shop, I'd call
Lenbrook Industries (800-263-4641) the NAD distributor and ask them for
an authorized shop in your area.

There is one service bulletin on the 304 which applies to serial
numbers BELOW M323048463 where R 917 and 918 in the power supply are
change to 180 ohm 1 watt, flameproof resistors. (Some earlier units
might have 2 470 ohm resistors in parallel.) If these fail, the preamp
power supply will no work, and neither will the preamp. This is
something you can check yourself IF you have an ohmmeter or a DMM and
know how to solder.

Depending on what has failed, I'd expect a repair to run between $50
and $100, unless something unusual (like the power transformer failing)
has occurred.

Regards,
Tim Schwartz
Bristol Electronics

[Tim Schwartz]

Derek,
Another service note I forgot about is to check R333(left) and R334
(right channel). These are 47K ohm, half watt resistors. If they open
the channel will have 10-15V of DC offset and the muting relay will not
turn on. (which is a good thing, otherwise you'd need new speakers too.)

Regards,
Tim Schwartz
Bristol Electronics

[g]

I too have a NAD 304 which died a year or two back. The red LED stays on
after switch on, with no output from the speaker outlets. If headphones are
plugged into the headphone socket, there are some LOUD cracks/pops and some
output in one channel, although it sort of sounds out of phase/not focussed,
and faint. When I opened it up, I noticed some blacking on the circuit board
towards the right hand side of the unit.

As you may have guessed, I have no technical knowledge with regard to
electronics, so I was wondering if the problem I have tried to describe
could relate to either of the problems you have detailed (possibly the
second one?) ?

TIA.

"Tim Schwartz" <tosch...@worldnet.att.net> wrote in message
news:3BD94A29...@worldnet.att.net...

[yac...@gmail.com]

See this excellent article about repairing the NAD 304

http://www.condoraudio.com/wp-content/uploads/Projects/NAD-304-Restoration-Repair-Upgrade.pdf