Dell Studio XPS 435mt won't power on - orange motherboard light


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Dell Studio XPS 435mt won't power on - orange motherboard light

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I've had my Studio XPS 435mt for the last few years and love it! I normally leave my machine on all day most days so I can access it remotely. Well, today my power went out (the machine is plugged into a good surge protector) and now it won't turn back on.

When I plug it in there is a green light on the back of the machine and internally there is an orange LED that is illuminated. When I press the power button nothing happens, no even attempt to power on. I have read a few forums that suggest everything from a new power supply, to a new motherboard, and even a random "put your motherboard in the oven" post.

So my question is can I do anything to verify what the problem is? Also, if it is a motherboard issue and needs to be replaced where is the best place to get a motherboard? Does Dell sell them directly or do I have to go to a 3rd party to track it down?

Thanks in advance for your assistance!

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  • A surge type power strip does nothing to protect the PC during a power failure.  You need a "UPS" unit to protect the PC during short (most) power outages.

    As it was running, anything could have happened from the power supply to the motherboard to a component on the motherboard. 

    As you have the "keep alive" power on the motherboard, indicated by the orange LED, the power supply is working somewhat.  Disconnect the 24 pin power connector from the motherboard.  Then jumper the GREEN wire to a BLACK wire and see if the power turns on (fan will run).  If it does this, it doesn't say the power supply is good (only replacing it with a known good power supply is the only real test for a power supply) but it does say the problem turning on is not in the power supply.  If it does not turn on, the power supply is the likely problem.

    If the power supply turns on the next most probable problem is the motherboard.  reseat (unplug and plug back in) the front panel connector on the motherboard and then give it a try. If it still will not work, the motherboard is suspect.  The power switch, itself, would be a very remote problem.

    Dell is one source for a replacement motherboard.  There are sites that sell used/refurbished Dell motherboards and can be found with a google search.  Only another exact replacement motherboard will fit and work.

    Finally, whatever tests you do or whatever seems like it isolates it to a certain part, unfortunately only replacing the part will really tell if it's bad.  To avoid buying something you don't need you may want to take it to a reputable PC repair to find out what is really wrong. 

    I am not a Dell Employee

    Dell forum member since 2002

    Home Built PC with Gigabyte GA-Z77X-UD5H motherboard, i7 3770 CPU,  Windows 7 64 bit Home/Win 8.1.  SSD drive.  Sonar X3c 64 bit Recordng Software.


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  • I have exactly the same machine, a Studio XPS 435mt, which ran into the same problem today.  It happened after a proper shutdown due to an anticipated power outage and it wouldn't power back on later.  It had a green light at the back indicating the power supply was active and a yellow light inside indicating the motherboard was receiving power.  It was also plugged in to a UPS but would not respond to the power switch.

    Went through the basic steps: removed two power connectors and reseated them, removed RAM and reseated it, removed front panel connectors and reseated them.  Then I removed power and SATA cables from all drives and removed all cards (including the video card).  After plugging in power, it responded to the power button and began to boot.

    Following a process of elimination, it turned out that a secondary network card was preventing the machine from booting.  Now, with that card out, it is running again.

    Just note, this machine will not respond to the power button for at least 10 seconds after the plug is inserted in the power supply.  The green light at the back will blink during that period.

  • Just had something similar.  Did a normal shutdown, and moved the system into another room while I spent the weekend re-configuring my office.  Brought it back, plugged it in, and *nothing*.  Actually, *almost* nothing. Shortly after hitting the power button, the case fan, CPU fan and PS fan would move for a split second (partial revolution to a coupld of revs).  If you weren't looking at the fans you wouldn't know, because there was no noise - just a split second of movement.

    Tested the power supply by disconnecting the 24pin connector and shorting the green wire to ground - power supply came up, all voltages just fine.

    (See for directions.  Note that he describes the 20-pin connector - for the 24-pin connector just look at the color of the extra four wires - each color has a particular voltage.  Also note that there's some debate about whether PS voltages are erratic under zero load - one suggestion was to connect a single (old if you're paranoid) disk while testing.).

    One site even had a comment from someone who inserted a paperclip into the 24-pin connector to ground the green wire.  System runs fine (although the fans scream until first boot) but you have to unplug it to shut it down.

    Even though the PS tested fine, I went out and bought a new PS (Antec HCG-620m) and tried that.  System runs fine now - it was a bad power supply.


    ps: I know that the 620 watt power supply was overkill - even with the GT 545 card that I have.  Two reasons for the big PS:

    1. I'll be replacing this system with a DIY Ivy Bridge when prices settle down, so I bought a PS for the new system.

    2. If the problem had turned out to be the mobo, I would have grabbed a cheap X58 mobo, bought the case for my upcoming Ivy Bridge, and put the 435MT CPU, my 24 GiB of RAM, and option cards into the new case.

    pps: A standard ATX power supply works fine, but take note of the depth of the PS.  The stock PS on the Studio XPS 435MT is 5.5" deep. The HCG-620M is 6.3" deep, and the clearances are *very* tight between the PS and the stock Dell BD drive.

  • I had to reply because at least some of us are onto the same exact issue here.  I just recently had the integrated NIC on my Studio XPS 435mt go out.  I bought a new PCI-e network card and installed it to get going again - all worked just fine.  Then recently a power outage happened and improperly shut down the PC.  I'm not sure why that would have any effect, but when I tried to turn it on I got nothing.  Same steady amber light on the MOBO and green on the power supply.

    I read this post and that got me thinking about the NIC.  I noticed that when I I unplugged the ethernet cable, the light on the MOBO and the green power supply light on the back of the PC both sort of flickered steadily.  When I plugged the cable in they were both steady.  I removed the PCI-e NIC, plugged in the power and it booted right up.  So there is clearly a design flaw of some sort with this mother board and it's very frustrating.  I even tried switching to the other available PCI-e slot, but got exactly the same result.  Now all I can think to do is to try a USB NIC or go wireless.

  • Or, try a new power supply.

    It seems to be that for several of the posters here the OEM power supply weakens over time - and at some point in time the system does not reboot after the power is cycled.

    If you get a USB NIC, you may simply delay the "will not boot" issue for a few months.  (And suffer slow network speeds before the inevitable failure....)

    The 435MT was a bargain system 4 years ago.  It doesn't bother me at all that some of those 4 year old power supplies are failing - since power supplies are cheap and easy to replace.

  • Thanks for the great info.  I'm having the problem discussed here and thought I'd need an ATX power supply for replacement because of the location of the fans.  The pwr supply you bought has the fan on top (or bottom?) so I didn't think that would work. If it exhausts to the top then it's just blowing hot air to the top of the case, not exhausting it.  How did you mount the ps?  thanks.

  • The screw holes on an ATX power supply are asymmetric - it will only go in one way.

    They also exhaust out the back (pull air from inside the case, and push it out the back) regardless of where the fan is located in the power supply.  (Historical note - originally ATX was specified that the PS would inhale - but it was realized what a bad idea that was.)

    I've never seen a power supply that didn't have the fan in the back or on the bottom (assuming top-mount power supply).

    Check the image - note that the bottom (top in the picture, but bottom when installed) screws are in the corners of the PS.  The top (bottom in the picture) are not in the corners.  The fan is on the side where the screws are in the corners.

    As long as the fan on your PS is in the back or on the side with the screws in the corners, you'll be OK.

    Do note that the original PS on the 435MT isn't very deep (front to back dimension).  I went with one about a cm deeper, but anything more than that would interfere with the connectors on the back of the BD/DVD drive.

  • I have the same issue on my xps 435mt ittle flash of light on the power button.  I am guessing power supply.   Every computer I have had has a PS death, except my last dell which is why I bought another.  I am guess this is the right one  I have upgraded my drives to an SSD and tarabyte drive.  Should I get a bigger PS?

  • I am writing from the formerly dead PC.  I have the new power supply listed above.  The power supply was not identical, but very close and 5 more watts of power.  Having had a PC since the early 90's I have changed many power supplies.  Every computer except the last one had a power supply die.  The symptoms are usually strange component performance.  This time it just died with the power button flashing yellow when I pressed it.  It is hard to understand why a power supply is such a breakable component.  I bought dells because I thought the build quality on average was higher.  With this PC I have to say the component quality is average.  I have had a dead hard drive and a dead power supply after three years.  This is normal for a self made PC.  I thought dells were better, but I guess not.  If your computer does not turn on and there are no motherboard beeps then the problem is most likely a power supply.  Don't waste your time with testing just replace the power supply.

  • I ordered the same PS but when I removed the old one and attempted to install the new PS, I discovered there was no way the new PS was going to fit in to the same spot.  I had some room for additional depth, but no wiggle room for height.  I have to return the unit to Amazon and keep looking for one that will fit I guess.  Does anyone have a link to the ATX PS that was pictured in the thread?

  • This fits into tight spots:

    I have one in an XPS 7100 chassis.

  • This problem happened to me last week and googled for the Dell Xps Studio 435t not powering up. The computer shut down several times with the last time not responding to the power button, checked to see if all fans were working, they were.....disconnected all external devices to include all optical drives and internal hard drives, except for the boot drive, still would not start up, I thought it might be the power switch being worn out. Disconnected the video card, no still would not start I removed all network cards, sound card,video card, TV card, USB 3.0 pci-e card, USB 2.0 Pci-e card.....and guess what.....the damn computer started I am thinking in might be the PS, Motherboard or power I installed the cards back one at a time, starting with my video card and left the TV card and the USB 2.0 PCI-e card out...don't need is working fine the issue was with one of the cards which I can do without....I was hoping it wasn't the motherboard.....that could have been costly....

  • Similar problem with the Dell Studio XPS 435MT

    Symptom and Troubleshooting steps:  Found computer in a hung up state trying to shut down after what I assume was a auto-update.  It would not complete the shut down sequence.  I eventually held the power button in to force a shutdown.

    After waiting a few minutes I attempted to re-boot.  The computer would not power up.  I found that the fans would just barely kick over.  No light on the power button.  Though the power supply light on the back panel was lit green.  The motherboard had a steady orange indicator light lit up.  There were no audible beeps.  I eventually unplugged all the drives, graphic cards, monitors, and external USB connections.  Disconnecting anything that would cause a load.  I attempted to power up.  Same fan kick, then nothing.  I pulled the power supply and on the 24 pin connector jumpered the green wire to one of the black wires.  The Power supply fan powered up and ran.  I was kind of reluctant to think the power supply was bad.  I didn't have a chart of the voltages and didn't test further.  So many articles on the web about the power supply going out I purchased a replacement off eBay for $47 including priority shipping.  The original PSU was a 300 Watt. Model PS-5361-2   I upgraded to a  480 Watt from KDM Power off eBay.  They shipped fast.  It was at my door 3 days after I ordered it.

    Plugged the new PSU in and I was back in business.

  • I too this morning suffered from having my mt435 not boot. I read this forum question including your steps on checking your PC to check for all possibilities. Your comments were right on the money. I usually am quite forgetful when it comes to cleaning out my pc with compressed air, as it gets really dusty where I have my PC in the house. This shutdown has happened to me before and simply unplugging everything and giving the inside chassis a nice through cleaning has done the trick for me. Unseating cards and memory isn't probably a bad thing to do either in combination with the cleaning.

    Like the others, my green light was on indicating there was power going to the power supply and my amber light was lit on the motherboard. I bought this unit, the MT435 now 5 years ago, and like the others in this forum I really like it, although I wish at times it wouldn't sound like a hair dryer when I am putting it through it's paces with video editing and stuff like that.

    The key as you said was waiting a minute or even a few minutes after the PC is plugged back in again and giving the power supply a bit of time to get back up and running. Not sure if this is really the precursor to a part on this PC failing though, it seems like it shouldn't be doing this. We'll see what happens in the near future of it this was just a fluke. Thank god as well, because as usual I wasn't backing up my needed files either, which is a huge no-no, I know what I am going to be doing as soon as I put my MT435 back into the desk case. Back up! Back up!

    Thanks for your sage advice!


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