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August 2nd, 2015 01:00

XPS 8700 Power Supply Replacement

Hey everyone,

After a bad storm, my XPS 8700 won't power on. I tried the self test on the power supply and a green light turns on with the fan running. Inside the motherboard has an ambler glow. Is it still possible the power supply has gone bad? And can anyone recommend a replacement (Nothing too expensive or a significant upgrade since I don't use this pc for games)? I fear the motherboard is bad but hoping its just the PSU.

Thanks for your help!

Ryan

1.2K Posts

August 2nd, 2015 11:00

I suggest the paperclip power supply test and measuring voltage with a multi-meter.

http://support.antec.com/support/solutions/articles/1000015319-is-my-power-supply-dead-the-paperclip-test

If it is dead, The Antec green series have worked well for me in the past. right now it is $29 after rebate.

http://www.newegg.com/Product/Product.aspx?Item=N82E16817371086

the corsair cx-500 is also a decent budget PSU, is on sale today and has a rebate.

http://www.newegg.com/Product/Product.aspx?Item=N82E16817139027

I would not consider these if an aftermarket gaming graphics card was being used, but for a replacement PSU they should be fine. 

I'd read the reviews of any PSU before buying.

9 Legend

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47K Posts

August 3rd, 2015 07:00

Corsair CX series wont work.  You need to look at a power supply as a multi output unit not a single 12v WATTS spec.  The 1XMMV 460W unit that comes with it has specific spec including dimensions.

Note this Dell 525W unit allows for 150W on the 3.3v/5v rails and 20W on the +5VSB rail.

http://www.amazon.com/1XMMV-Switching-AcBel-AC460AM-00-Tower/dp/B00ZSXHTU8

 

You need an EPS12V unit that meets dell's spec.

This is why Corsair CS750M is minimum recommended unit.

The 5v must put out 25 to 30 Amps, and the 3.3v must put out 20 to 25AMPS.

Dell's 5vsb is 4 AMPS aka 20W.

http://www.amazon.com/Corsair-Series-Modular-Efficient-Supply/dp/B00GH9NA0A


ANTEC 650W Green power supply puts out LESS THAN 100W on the 5v/3.3v rails which is not enough.

Dell performance units put out 225W on these rails alone.

 The other reason for this SPECIFIC power supply are the dimensions.

If its too long it won't physically go in the case.

 

http://www.microcenter.com/product/425477/CS_Series_CS750M_750_Watt_ATX_Modular_Power_Supply

http://www.amazon.com/Corsair-Series-Modular-Efficient-CS750M/dp/B00GH9NA0A

http://www.corsair.com/en-us/cs-series-modular-cs750m-750-watt-80-plus-gold-certified-psu

 

4 Posts

August 2nd, 2015 17:00

Thanks, Dan! I'll give it a shot

4 Posts

August 3rd, 2015 10:00

Thanks alot, Speedstep! Just cancelled my previous order. Going to order the CS750 now!

1.2K Posts

August 3rd, 2015 11:00

once again I'll disagree that a Desktop needs a server class spec PSU hence no reason for an EPS v9x spec.

Both PSUs listed are sufficient for the 8700, and certainly for one without a high-end graphices card.

The primary difference from EPS v91 and ATX v3 is the CPU connector must be 8 pin, which means nothing on an XPS 8700 since it has a 4 pin CPU connector.

The other relevant updates also do not apply to lower power PSUs.

spend more if you want but it is not necessary -- especially if you are staying with the stock graphics card.

 

9 Legend

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47K Posts

August 3rd, 2015 13:00

You are ignoring the Spec for all of the other rails and depending on 1 spec for 1 rail at 12v being a working power supply. Corsair CS750 has a break away 20/24 connector with multiple PCI-E 6 pin or 8 Pin connectors and a Break away EPS 8 pin that can be made ATX 4 pin.

ATX and EPS 12v are more than just connectors.

The system needs 20W on the +5vsb because it supports more than 8 gigs of ram and S3 power mode.

The system needs 25 to 30 Amps on the 5V rail and 17 to 25A on the 3.3v rail and around 130 to 150w combined minimum for that rail set.

The EPS specification unlike the ATX specification says that 5VSB is 4AMPS or even 6AMPS and that 5V is guaranteed 30AMPS and the combined Rails 170W for a reason. If you look carefully at All the models from 305W to 1000W or more the 12v rails are separated into 18 Amp Sets.   The 5VSB is 4A and the 5V is 25 to 32 Amps the 3.3v is 17 to 30Amps, the -12v is constant .3A to 1A and the Number of 12v rails grows as the wattage Grows.  The other thing to be watching is that the +5v/3.3v goes from 150 to 170 to 225W for the various dell power supplies. Dell M1J3H 525w

Several Suggested Power supplies have 130 or 120 or less than 100W for the 5v/3.3v rails which lead to issues or even damage if the power supply doesn't have over voltage over current crowbar protection.  That can lead to 100 percent Fried system including but not limited to dead cpu, dead ram, dead hard drive, dead video card, motherboard fire and over all dead done stick a fork in its over. 

Recommendations should be made on the basis of SPEC for ALL Rails not a single 12v Rail Spec of total Watts.  The cost difference between a CX500 and CS750M is often $19 or Less.

http://www.amazon.com/Corsair-Modular-Efficient-Supply-CS750M/dp/B00GH9NA0A

http://www.amazon.com/CORSAIR-ATX12V-BRONZE-Certified-CP-9020047-NA/dp/B00MZ4N286

 


The 525W DC Output on later models adds more to the +5V rails.

For larger units the +5v rail goes to 30A or more.

+5V 22A

+3.3V 17A

+12VA 18A

+12VB 18A

+12VC 18A

-12 1A

+5Vfp 4A

+5V and +3.3V shall not exceed 150W

+12VA, +12VB and +12VC shall not exceed 500W

 

Lets look at the CX500 reality distortion.

If you get 456W from the 12v rails that leaves 4W for EVERYTHING else. 

Corsair CX500 ATX Power Supply
DC Output Rating
DC Output +3.3V +5V +12V -12V +5Vsb
Max Load 25A 20A 38A 0.8A 3.0A
Maximum Combined Wattage 120W 456W 9.6W 15W
Total Power: 500W


Now lets look at the Dell 460W power supply.

NOTE the 25A on +5V 17A on 3.3v with Combined 142W

Note also that the supply is balanced with 385W max on the 12v combined output.

+5V SB is the same here at 3A or 15W

 


1.2K Posts

August 3rd, 2015 14:00

spend more if you wish, it is your money. 

I again completely disagree with about half of what speed step writes but I don't have the time to pick it apart (again).

a CS 750 is 1) not a very good power supply for the price and 2) overkill for an 8700 when not used as a gaming system that has a power hungry aftermarket graphics card.

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