Dell XPS 420 does not boot

  howard64 18:44 02 Jul 2010

I have been asked to look at the above system - what a beast. It is a core 2 Viiv with vista. It has 2 large hard drives and is packed with many gadgets. The owner suspects the power supply which is a special Dell unit with extra long sata power supply leads which go under the motherboard to the drives. I have temporarily connected an ordinary power supply but I just get 1 continuous screech and it still does not boot. With its original psu connected the fans all run including the one on the monstrous dvi graphics card. There are no beeps and just the sound of the fans running. Does anyone have any suggestions?

  Fruit Bat /\0/\ 19:05 02 Jul 2010

CAn you hear Hard drive running?
It may be booting but graphics failure.

Try unplugging every thing except 1 stick of memory, graphics card and the main hard drive.

  howard64 10:53 03 Jul 2010

with everything unplugged and different single strip of memory still nothing but can hear hard disk and main cpu fan running - the fan in the psu is not running so it could be the power supply is faulty.

  Fruit Bat /\0/\ 13:53 03 Jul 2010

"but can hear hard disk and main cpu fan running" good news, but my graphics failure.

"the fan in the psu is not running" unusual if its still powering the board, could be correct psu failure so no power to graphics therefore cannot see it booting.

I think you need to try another PSU first.
Also worth removing and refitting graphics card to remake contacts and retry.

  howard64 14:08 03 Jul 2010

I have even removed the monster unit which has a fan on it and that was rotating and put a normal pci-express good working card in with no difference. I have now put everything else back as it was. Does anyone know where one can buy a replacement psu for this pc?

  northumbria61 14:21 03 Jul 2010

most atx power supply's should fit but an option is either the ANTEC EA500 or EA650... available from Amazon UK and other suppliers

  northumbria61 14:26 03 Jul 2010

Antec EA500 - click here

Antec EA650 - click here

  Fruit Bat /\0/\ 14:32 03 Jul 2010

If renewing a PSU check:

1. The physical size of your PSU, some are hard to replace due to being a non standard size.
2. The amount of power need from the PSU don't skimp.
3 The correct connections for your equipment

1. Physical Dimensions

Besides the specs and form factors, the physical dimensions are also important factors in selecting a compatible power supply. Here is an outline of the physical dimensions of most standard power supplies:

# ATX: 6x3.5x5.5", HxWxD. Most common. Uses 4 mounting screws.
# Mini-ATX: 5x3.5x5", HxWxD. Rare size. Uses 4 mounting screws. Can be used in a regular ATX case, but often not the other way around.
# MicroATX: 5x3x4", HxWxD. Use 3 mounting screws. Not interchangeable with ATX or miniATX.
# Flex ATX: Even smaller than Micro ATX. Various sizes according to case specs; often not interchangeable.

Use the data above to determine if a particular power supply would fit your case.

The quality of a power supply can be estimated by its weight. While this is not a true scientific or thorough measurement of the power supply reliability, it is nevertheless a very simple and easy way for ordinary PC users to estimate and compare the quality of a power supply. Why weight matters click here

2. Power supply calculator click here

3. Correct connections
Some boards have 20 pin connectors others 24 pin
There is often a 4 pin plug required to power Intel CPUs
Molex D plugs for IDE HDD and CD/DVD drives
SATA power connections for latest HDDs and DVD drives.

Guide to changing PSU
click here
click here

  howard64 14:57 03 Jul 2010

as I have said this appears to be a special unit built for dell and as such will have to be replaced by either a dell unit or one built as a substitute for the dell one. Dell do not appear to sell parts for their pcs, at least, I cannot find anywhere to buy a replacement psu from them.

  northumbria61 13:03 04 Jul 2010

It appears that your replacement PSU does not have to be a special Dell unit or one built as a substitute for the DEll one. This link I know is an old POST click here but if you read it fully does give you options.

I referred to the Antec earlier but also the Corsair 650W is mentioned in the post - although the link to purchase is to which is U.S. based these are readily available in the U.K.

The Corsair models come with a 5yr Warranty.

click here

  northumbria61 13:06 04 Jul 2010

It seems the hardest part is getting the wires out from under the processor and fan shroud without removing it.

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