My Nad S300 Amp stopped working any help please

[zzag]

Hi,

My old trusted Nad S300 amp has stopped working.

The fault starts on the left channel it pops loudly, then left speaker stops working. Then the power light on the amp flashes fast and music then stops from the right channel. I have done all the usual stuff changing leads, and speakers etc.

Does anyone know where I can get my S300 amp repaired and serviced please. I live the North west near the Wirral though I would post the amp (it weighs 25kg).

Also does anyone have any idea what sort of price I am looking at.

Any help will be appreciated.

[walpurgis]

http://theartofsound.net/forum/showt...rvices-offered

Or, https://www.sevenoakssoundandvision....x#pgnum=&sort= They are UK distributor for NAD I believe.

[zzag]

Thanks for the reply Walpurgis.

I will get onto both tomorrow when i have time.

[Stratmangler]

I'd be wary of the Sevenoaks route - they'll factor a large wedge for themselves into proceedings.

[jandl100]

I had a S300 for quite a while - lovely amp, it saw off many a well thought of competitor during its stay!

Mine did have some issues - it developed a weird kind of intermittent fault where it made strange pinging noises through the speakers and just sounded 'not right' sometimes.

I took it along to http://fixmyamp.co.uk/ and Brian there had a good look but couldn't find any specific fault - but he did think that the soldering was getting a bit iffy, so he re-soldered the lot for me. He said it took a whole afternoon and his back was killing him for a week afterwards! That cost me £150 iirc.
But it did solve the issue as it worked fine after that.

I don't know if that helps or not!

[sq225917]

How quickly does it go from one side to the other, couple of seconds or more like thirty?

First off inspect all the bits, reflow any dodgy joints, replace any bad parts. Then split it left right and check pre and power sections on their own. Odds are you'll find it by then.

Its meant to be dual mono though, so short of an earth failure or bad transformer nothing should effect both channels.

Ill take a look for free if we can find a circuit diagram for it.

[sq225917]

Found a circuit for it, let me dig into it for any likely culprits

[sq225917]

Ok, looks like there's an octet of ztx transistors surround by a couple big resistors that scorch the board and trip the protection. Pop the lid and look for brown areas on the pcb.

[zzag]

Sorry about taking so long to reply I've been ill, right thanks for the advise, I will take the lid off when I'm a little better. The amp weighs 25kg and so just moving it right now is out of the question. When I am feeling better I will take your advise and post again and try to post pics.��
@Sq225917 are you an electronics engineer who fixes hifi etc.

[Manicatel]

I'd be wary of the Sevenoaks route - they'll factor a large wedge for themselves into proceedings.

Categorically untrue.