XPS DR Blowing Fuses - guidance required

The transformer is secured by a large central bolt. So the feet will not impact that if removed - they will allow the case to slde off though. However, unless you are confident you can fix the unit and it is out of warranty, I would not bother opening it no matter how trivial the task may be or competent you feel.

Undoubtedly the forum will have plenty of advice. I'd just raise a support ticket with Naim though or contact the dealer. They will run though the normal checks of confirming which fuse you are referring to (the one in the plug for UK model or the one in the unit for every region model), and possibly some sanity checks like replacing the fuse and plugging into another mains socket on a different circuit. You can probably save some time by doing these before raising a support ticket with Naim/the dealer. Also, make sure the fuse used (in in the unit) was the right type for your region. These may differ if you moved from a 240v country to a 110v country and had the unit rewired. 

The fact the fuse is blowing is good. There is clearly an issue and it is doing it's job.

feeling_zen posted:

The transformer is secured by a large central bolt. So the feet will not impact that if removed - they will allow the case to slde off though. However, unless you are confident you can fix the unit and it is out of warranty, I would not bother opening it no matter how trivial the task may be or competent you feel.

Undoubtedly the forum will have plenty of advice. I'd just raise a support ticket with Naim though or contact the dealer. They will run though the normal checks of confirming which fuse you are referring to (the one in the plug for UK model or the one in the unit for every region model), and possibly some sanity checks like replacing the fuse and plugging into another mains socket on a different circuit. You can probably save some time by doing these before raising a support ticket with Naim/the dealer. Also, make sure the fuse used (in in the unit) was the right type for your region. These may differ if you moved from a 240v country to a 110v country and had the unit rewired. 

The fact the fuse is blowing is good. There is clearly an issue and it is doing it's job.

Safe advice. It is the unit fuse not the plug. I know it is the correct fuse as i purchased 10 eighteen month back when I had the issue the first time. Not too worried about the fuse blowing - rather the nature of the blows and whether I have got any 'debris' in the unit.

Alan Willby posted:

I know it is the correct fuse as i purchased 10 eighteen month back when I had the issue the first time.

Just to check - these were the same Littel Fuse brand as supplied?

https://forums.naimaudio.com/to...22#19447375214204422 

"Naim have found that fuses of the same rating but different manufacturer do not provide the same outcome when used in Naim units.
In Production and Service we use fuses from a specific series within the Littel Fuse Company range. We strongly advise you continue to use the exact same as replacements.

These should be readily available from your Naim retailer – although some will source their stock elsewhere. You should check that your Naim retailer carries a full range of spare fuses – either from Naim Salisbury or the exact same items from a Littel Fuse supplier.

Fuses of the correct rating from other manufacturers may work and should be safe. However, some Naim units make greater demands on the rating (the XPS-2 for example) and non-Littel fuses are likely to rupture – always or more often."

Adam Meredith posted:

Alan Willby posted:

I know it is the correct fuse as i purchased 10 eighteen month back when I had the issue the first time.

Just to check - these were the same Littel Fuse brand as supplied?

https://forums.naimaudio.com/to...22#19447375214204422 

"Naim have found that fuses of the same rating but different manufacturer do not provide the same outcome when used in Naim units.
In Production and Service we use fuses from a specific series within the Littel Fuse Company range. We strongly advise you continue to use the exact same as replacements.

These should be readily available from your Naim retailer – although some will source their stock elsewhere. You should check that your Naim retailer carries a full range of spare fuses – either from Naim Salisbury or the exact same items from a Littel Fuse supplier.

Fuses of the correct rating from other manufacturers may work and should be safe. However, some Naim units make greater demands on the rating (the XPS-2 for example) and non-Littel fuses are likely to rupture – always or more often."

Actually no - they were from Maplin (shock horror!!) actually - but the first one I used worked ok straight off. Perhaps it was the only good one. The one I originally replaced was unbranded as far as I could see - and there was no spare (it was an ex-Dem purchase from a Naim dealer) so perhaps my XPS had already been chewing a few up.

I will source some Littel ones and see if that cures the issue.

Curious that the XPS makes greater demands than a SC and 250.

Thanks for the advice

I think your problem is that you bought regular 2.5 A fuses and they are fast blow. The correct ones for Naim equipment are slow blow. This is so they can cope with the big surge at switch on.

If you happen to turn the unit on when the AC is at or near maximum, you will get a big surge that can blow the fuse. If you happen to turn on at the point the AC is crossing zero, there will be no surge. The surge is also worse when the unit is cold than if it is warmed up.

Anyway I doubt there is anything wrong with the unit and if you get the fuses from your Naim dealer, all will be fine.

best

David

I just had the same issue with my XPS2 which blew the fuse after 4 months being turned off. I believe the fuse which blew was a Maplin one but the 2nd one I fitted was a Naim recommended Littel Fuse Company (I bought from RS Components), and that worked fine - touch wood!  

Naim reckon Littel fuses sound better but the key thing is the slow blow spec. So if you fit a fast blow Littel fuse, it will blow just like a Maplin one.

The Littel slow blow fuses have a sort of coil inside instead of a straight wire and they have a T on the end cap where the current and voltage rating is stamped.

I'm just looking at some I got from my Naim dealer for my CDX2, which also likes to express itself by blowing a fuse at switch on occasionally!

The link in Adam's post is worth a read too....

best

David

David Hendon posted:

I think your problem is that you bought regular 2.5 A fuses and they are fast blow. The correct ones for Naim equipment are slow blow. This is so they can cope with the big surge at switch on.

If you happen to turn the unit on when the AC is at or near maximum, you will get a big surge that can blow the fuse. If you happen to turn on at the point the AC is crossing zero, there will be no surge. The surge is also worse when the unit is cold than if it is warmed up.

Anyway I doubt there is anything wrong with the unit and if you get the fuses from your Naim dealer, all will be fine.

best

David

No they are specifically slow blow

blythe posted:

I just had the same issue with my XPS2 which blew the fuse after 4 months being turned off. I believe the fuse which blew was a Maplin one but the 2nd one I fitted was a Naim recommended Littel Fuse Company (I bought from RS Components), and that worked fine - touch wood!  

Thanks - I'll look them up. Only site I have found so far seems to be an importer.

I am sure that any Naim dealer will happily put a few spare fuses of the correct type in the post for you. Then as others have stated all should be fine. 

Your Naim dealer or distributor should be able to supply the correct fuses.  Failing that, if in the UK, then contact Naim directly.

Richard Dane posted:

Your Naim dealer or distributor should be able to supply the correct fuses.  Failing that, if in the UK, then contact Naim directly.

Thanks Richard. I'm going to make a couple of calls today. Sort of on the same subject I wonder if part of the issue is how securely my Powerline is connected. I have read your advice in previous threads and have pushed it in as far and as hard as I can - but have not really felt a point of resistance - should I? I assume I use the back plate of the plug to apply the pressure - not the silver body. I am not a complete novice - I have PL's on the SC and 250 and have never suffered a fuse blow on either of them.

Alan, a Powerline that's not properly connected will almost certainly arc and then blow the internal fuse on the XPS.  With the Pwerline it's important to grip the body of the plug as you push in.  The resistance is high - the jaws on the Powerline are as tight as regs allow as this performs best - so you'll know when it finally makes a proper contact. The rear black section of the plug then pushes back (hence why you mustn't hold this) as the plug decoupling takes place.  If it's not doing this then you aren't connecting properly.

This is the RS Components (Radio Spares) part number, if you're in the UK and, you feel it's more convenient than a dealer - for me, it's quite a distance to see my dealer and not very convenient)
I bought a pack of 10.
You can Google them for their web site.
Apologies if this might be contrary to forum rules.

Cartridge Fuse, T, 2.5A, 5 x 20mm, Glass
Stock no.: 541-2969

blythe posted:

This is the RS Components (Radio Spares) part number, if you're in the UK and, you feel it's more convenient than a dealer - for me, it's quite a distance to see my dealer and not very convenient)
I bought a pack of 10.
You can Google them for their web site.
Apologies if this might be contrary to forum rules.

Cartridge Fuse, T, 2.5A, 5 x 20mm, Glass
Stock no.: 541-2969

Thanks Blythe

I have been in touch with my favourite dealer and he is popping a couple of new fuses in the post to me - but I will order some as well as my supply of 9 is now down to only 2!! Might need some in the future for the SC and 250. My dealer said that the XPS is by far the worse component for blowing its fuse. Interestingly I have fired up the bare CDX2 for the first time ever while I sought out the XPS - guess what - blew its fuse (1.6amp version) !!, but the spare held. Whole thing is just a pain - no wonder we leave our equipment on once it is safely switched on.

Blythe, that's just fine and possibly easier for some.

Alan Willby posted:

blythe posted:

This is the RS Components (Radio Spares) part number, if you're in the UK and, you feel it's more convenient than a dealer - for me, it's quite a distance to see my dealer and not very convenient)
I bought a pack of 10.
You can Google them for their web site.
Apologies if this might be contrary to forum rules.

Cartridge Fuse, T, 2.5A, 5 x 20mm, Glass
Stock no.: 541-2969

Thanks Blythe

I have been in touch with my favourite dealer and he is popping a couple of new fuses in the post to me - but I will order some as well as my supply of 9 is now down to only 2!! Might need some in the future for the SC and 250. My dealer said that the XPS is by far the worse component for blowing its fuse. Interestingly I have fired up the bare CDX2 for the first time ever while I sought out the XPS - guess what - blew its fuse (1.6amp version) !!, but the spare held. Whole thing is just a pain - no wonder we leave our equipment on once it is safely switched on.

Funnily enough my CDX2, which was ex-demo from my local dealer, blew its fuse the first time I started it at home and I found the spare was missing, so it obviously had previous in this regard! The dealer had just closed for the weekend, locking the door as I carried my newly-acquired CDX2 out, so I made do in a way that I won't discuss here (as Richard is watching) and got the correct fuses from my dealer a few days later. This was two years ago and for the reason Alan gives, I haven't turned the CDX2 off since.

best

David

David Hendon posted:

Alan Willby posted:

blythe posted:

This is the RS Components (Radio Spares) part number, if you're in the UK and, you feel it's more convenient than a dealer - for me, it's quite a distance to see my dealer and not very convenient)
I bought a pack of 10.
You can Google them for their web site.
Apologies if this might be contrary to forum rules.

Cartridge Fuse, T, 2.5A, 5 x 20mm, Glass
Stock no.: 541-2969

Thanks Blythe

I have been in touch with my favourite dealer and he is popping a couple of new fuses in the post to me - but I will order some as well as my supply of 9 is now down to only 2!! Might need some in the future for the SC and 250. My dealer said that the XPS is by far the worse component for blowing its fuse. Interestingly I have fired up the bare CDX2 for the first time ever while I sought out the XPS - guess what - blew its fuse (1.6amp version) !!, but the spare held. Whole thing is just a pain - no wonder we leave our equipment on once it is safely switched on.

Funnily enough my CDX2, which was ex-demo from my local dealer, blew its fuse the first time I started it at home and I found the spare was missing, so it obviously had previous in this regard! The dealer had just closed for the weekend, locking the door as I carried my newly-acquired CDX2 out, so I made do in a way that I won't discuss here (as Richard is watching) and got the correct fuses from my dealer a few days later. This was two years ago and for the reason Alan gives, I haven't turned the CDX2 off since.

best

David

I am never switching off again. I have always liked the quirkiness of Naim's approach to design - but on the other hand you would not put up with a vacuum cleaner that blew a fuse every other time you switched it on. You would have thought there must be some solution out there.