HDX start-up failure

Last night I switched on my amps for the first time in a couple of weeks and had problems with them tripping the circuit. This isn’t unusual, but it was several times instead of just the once. I also had powerline problems (HDX not connecting to network) and had to remove and replace the adaptors. Net result, the power to the HDX was improperly switched off several times because I wasn’t paying attention. I’ve tried to start several times but the screen remains at Starting…

I found this thread and have plugged in a monitor. HDX won’t start up

There’s a warning message: CPU has been changed or CPU ratio changed fail. Please re-enter CPU settings in the CMOS setup and remember to save before quit.

Does anyone know what the CPU settings should be? I guess I’ll need to find a keyboard too!

This almost certainly means the CR2032 battery backing up the CMOS is flat. It’s easy enough to change if you are confident of going inside and understand about electrostatic discharge protection.

Once you have changed the battery you need a VGA display and a PS/2 or USB keyboard. Then when it boots up you will get to the screen that invites you to accept the default CMOS settings, but you instead navigate across the screen to accept the Naim defaults. It should all be smooth sailing from there.

There are some threads about this here. They all talk about the Unitiserve, but I believe it’s the same for the HDX.

Post again here if you get stuck and one of us can alert Naim’s genie NeilS who will probably be able to guide you better than me.



Thanks David. It’s a 2015 model, which strikes me as slightly early for a battery to fail, but nonetheless it’s an easy fix to try.

I would agree with David that checking the CMOS battery would be worthwhile. I can’t help feeling a little nervous on your behalf when you mention powerline adapters. All the more so considering the lightning that’s been around recently, which might have upset your network directly if you have a copper phone line providing your internet connection, but is even more exposed to a surge when you run it on your mains electrical wiring.

It really isn’t too early for a 2015 model to have a battery fail. In fact a good friend of mine had exactly that with his 2015 Unitiserve about a year or more ago.



Got the case off and now looking for the battery location!

Bloody computers!
Happiness is conventional HiFi :stuck_out_tongue_winking_eye:


I’ve had this same problem on my elderly HDX, and it seemed to have been caused by an improper switch off too.

A quick visit to my dealer, who hooked the HDX up to an external monitor revealed that the software had somehow become corrupted as a result of the above, but the issue was sorted in a matter of minutes by him re-installing the software.

So, assuming you have a dealer nearby, I’d recommend a visit, and have him replace the CMOS battery at the same time.

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Battery found and replaced, rebooted and all back online. I even re-entered the date in CMOS. Bit of a faff in that I had to go out and buy a battery and search for allen keys, but really quite straightforward. Many thanks for the help, davidh, much appreciated.


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