Naim 300 Power Amp Problem

The internal fuse may have blown - it should have from what you did. There is a spare so try it and see if it is that.

Just for clarification, why was the amp disconnected in the first place?

If it's not turning on at all then the second "pop" may have  been the fuse blowing.  It is next to the IEC inlet - you should have a spare inside the holder, otherwise your Naim dealer can supply the correct type.

Also check that the front on/off switch latches in the "on" position. For a while my 300 would do exactly the same as you describe on switch on as it was essentially switching on and then off again. Best to check with the mains supply to the amp disconnected.

I turned it on twice and it did the same thing turn on and then after 10s turn off. It is therefore able to turn on but turns off. When in the rack I had the cables connected. I have taken it out of the rack now to ensure the Burndys are connecting correctly but there are no speaker cable connections. I want to now retest it now but I can't connect the speaker cables. Is that safe?

I'll recheck it is latching on/off. I suspect it is as it turns on but then goes off.

I guess if it does not switch on and stay on then a visit to Naim may be in order.......

I took it out of the rack in the first place to do some housekeeping but had to abandon that due to other reasons so put it back.

It's fine to switch on without speaker cables attached.  Do make sure though that the Burndy cables are properly connected and secured.

It is possible that the protection circuit operated and it takes a few minutes to 're-set.' I suffered such an event when the mains power had a brief and bumpy blip a few days ago. After I had extricated the PS and checked the fuse to find no fault, I called my helpful dealer and was advised to wait a few minutes. All was fine.

There was a very bumpy mains blip earlier a couple of years which caused the protection system on the 300PS to fail, but that did not prevent the PS operating. There was a very acrid smell though, mostly cured when the unit was serviced by Naim.

If it is turning on then off again by itself, and not blowing the internal fuse, it does sound as if there is a problem with the power button. 

I had a power button problem with my previous NAP300. The switch would latch intermittently and when it did let go would cause the symptoms you describe. I took the PS to my dealer and he soldered in the correct spare and all was OK. My be worth looking at that. The switch on mine started to feel a little 'soft before it finally gave up the ghost. Good luck.

George47 posted:

I connected up my Naim 300 and was greeted with the usual pop which after a few more seconds I got another pop and the amp and PSU turned off and the green logo lost its nice green glow. I checked everything and the Burndy cables were not locked in. I turned on the amp and same again.  I disconnected the inputs to ensure there was no DC leaking on but to no avail.

Can I check the speaker cables by completely removing them and trying to turn the amp on with input or output connections or is that ill advised. I can check the cables with a meter but would like to narrow it all down.

I will also leave it all off for a few hours and then try again in case it needs resetting.

Any helpful thoughts??

You should be able to turn everything on with no speaker cables connected. Its not a valve amp with output transformers

Guys,

I phoned the dealer I bought the used NAP300 from. Signals suggested to check switch on button and using their guidance we have found the switch on button is not working correctly. They are collecting the amp tomorrow and will hopefully do a simple change to allow the amp to get back to full operation. That looks to be problem and Signals are commended by me for providing excellent service even though it is some months since I bought the amps. Thanks guys for your advice you were right the switch on button has failed......

You are in very safe hands with Signals, and it sounds like it's going to be sorted out painlessly, which is great. 

Good news that you have found the problem and have a solution with the help of your dealer. 

Agreed and a useful reminder (to me at least) of the value of using a good dealer.

Chaps: Just to complete the tale. The amp was returned with a day or so turnaround from those nice guys at Signals. It is now all working well and nicely warmed up. Just need a good 282/252 to finish things of nicely......

Or a 552? Works really well with my 300.

And Signals are my local dealer. They have never failed to provide other than excellent service. (And good coffee.)

George47 posted:

Chaps: Just to complete the tale. The amp was returned with a day or so turnaround from those nice guys at Signals. It is now all working well and nicely warmed up. Just need a good 282/252 to finish things of nicely......

So what's your current setup George. Surprised that your reply implies you have a 300, but lesser supporting equipment.

Nick: I agree....

Graham: I have a collection to chose from but main front end is an Esoteric P03 and D03 into a Townshend Allegri preamp and Audionote Es. The Allegri gives a great sound but I listen off axis and need a balance control......the Naim preamps provide that but may not sound as good/different.

Thanks George. Must admit I had my Naim blinkers on when I asked the question.