Help me identify blown component Dell 8400

[Raul]

I have a Dell Dimension 8400 that won't power up and has a blinking orange light. I found a component with the board label of RT5B1, 1.5A, it is a surface mount component near the USB ports. It is to the right of the little box with the number 5, a similar component can be seen to the left of it. It is labeled X15 (one V on top of an inverted V), it is green and soldered on opposite ends, about 0.16" x 0.1" in size.

I looked through DigiKey but could not find one like this, it would help if I knew what I was looking for.

The motherboard has four of these but only one burned. I don't have a camera that allows close ups so this as the best I could do.

Any ideas? ....

[yyonline]

Re: Help me identify blown component Dell 8400

That's a surface mount fuse for the 5VDC power to the USB ports. It will cause a nonfunctional USB port, but it won't cause the PC to not boot.

Check for Nichicon HN or UCC KZJ capacitors that are blown. I've seen a number of these blown on Dimension 8400 boards. I've also seen a few Dimension 8400 boards with "turbo fan syndrome" and issues I've never been able to track down the cause of.

[Raul]

Re: Help me identify blown component Dell 8400

Thank you yyonline.
There are 6 bulging Nickikon HN (M) capacitors. The computer was running fine for several hours until shutdown and the next morning when I went to power up the computer, the UPS went nuts bipping nonstop, so I shut down the computer while it was booting, after that it would not boot up. I'll post again after I replace the caps and the fuse.
This computer came from our town's recycling center (the dump) which has many computers, I think I know why it was there. It worked flawlessly during the few days that it was working, the only thing strange was that it would not recognize 4 GB of RAM, it would show either 3 or 3.12 GB of RAM.

[yyonline]

Re: Help me identify blown component Dell 8400

You can order these as replacments for the 5x 10V 1000uF Nichicon HN capacitors:

https://www.badcaps.net/store/produc...products_id=47

If you order capacitors from elsewhere, make sure that they have the following specs:

ESR: 18 mOhm or lower
Ripple: 1760 mA or higher

Motherboard grade capacitors are a specialty item and not something you can find at most electronics stores.

Also carefully inspect the 6.3V 2200uF capacitor in front of the left side of the memory slots. That is another one that I frequently seen blown on these boards.

Before replacing the poly fuse for the USB ports, check the ports for physical damage. Often when I see blown fuses for USB, the ports have physical damage to them such as the 5VDC pin bent and shorting out to ground.

[momaka]

Re: Help me identify blown component Dell 8400

It worked flawlessly during the few days that it was working, the only thing strange was that it would not recognize 4 GB of RAM, it would show either 3 or 3.12 GB of RAM.

That's most likely a limitation of the operating system - all 32-bit operating systems will not recognize the full 4GB of ram. Some will recognize only 3.5 GB, others less.
If you're running Windows XP, you won't need that much anyways. XP runs great on 1 GB. If it doesn't, you definitely need to do some cleanup.

By the way, that polyfuse looks fine to me. Don't need to replace it if the USB ports are working. First replace the bulging capacitors - that's a lot more important and the likely problem with your computer.

[yyonline]

Re: Help me identify blown component Dell 8400

That's most likely a limitation of the operating system - all 32-bit operating systems will not recognize the full 4GB of ram. Some will recognize only 3.5 GB, others less

To elaborate further...

Even with a 64-bit OS chipsets prior to intel 965 will see < 4GB due to chipset limitations.

With 4GB installed, the BIOS setup should report 4GB. The OS will report less.

[c_hegge]

Re: Help me identify blown component Dell 8400

By the way, that polyfuse looks fine to me...

There are two in the pic. The one in the middle looks fine, but there is one to the right of it which is totally destroyed with a big burn mark around it

[TBoneit]

Re: Help me identify blown component Dell 8400

That's a surface mount fuse for the 5VDC power to the USB ports. It will cause a nonfunctional USB port, but it won't cause the PC to not boot.

Check for Nichicon HN or UCC KZJ capacitors that are blown. I've seen a number of these blown on Dimension 8400 boards. I've also seen a few Dimension 8400 boards with "turbo fan syndrome" and issues I've never been able to track down the cause of.

If as was indicated that blown device is a Fuse for the USB ports? Then I'd want to look at those ports and see if any of them are damaged with the pins shorting to each other or the metal USB port shell. I've seen that on Dells.

Not just 8400's with the turbo fan symptom, recall seeing it on some Optiplexes too. I do not recall the model. I searched the internet and never found anything pointing to what had gone bad. I did find one website that said they could repair the bad part. I didn't want to spend that kind of money or hope they were for real.

Now if I find that problem I just pull any good parts. Memory, PS, Drives & cards and scrap.

Now if I could just find out why a SX280 throws NMI's or be sure I can't find a cure. It does seeem to be tied to the Ethernet port, turn that off and it's good except only usb ports for replacing it.

[Raul]

Re: Help me identify blown component Dell 8400

Thanks to all that have replied. I did find a USB pin that was all crunched up and touching the metal casing. As yyonline mentioned, this should not prevent the computer to boot up so my blinking amber light is another problem (I read all the posts about the amber blinking light).

The picture shows one good fuse and a blown fuse to the right of it. DigiKey could not identify what this component is so I am still looking. They suggested a 1.5 amp fuse that is rated at 63 Volts but I have no idea if the voltage matters, yyonline did mention 5V for the USB ports.

I wanted to check if the on/off button has gone bad but I am unable to pry off the front of the computer.
I opened the power supply and nestled between the heat sinks is a slightly bulging capacitor, it looks like it might be a bear to get out due to the tight space.

As yyonline mentioned, I did see 4 Gb in Bios but not in the XP OS.

[yyonline]

Re: Help me identify blown component Dell 8400

They suggested a 1.5 amp fuse that is rated at 63 Volts but I have no idea if the voltage matters, yyonline did mention 5V for the USB ports.

1.5A sounds correct. USB is rated for 500mA per port. There are normally 2 ports to a fuse. Exceeding this by 50% would blow the fuse.

Voltage does matter, but it's a maximum rating. A 1.5A 63V fuse can interrupt 1.5A of current at up to 63V. Assuming it fits, this would be an okay replacement. That said, these fuses are very common on motherboards. If you have any dead boards around, you can probably salvage one from there.

I wanted to check if the on/off button has gone bad but I am unable to pry off the front of the computer.

It's possible to get the cover off of these things, but rather difficult. I've never seen the power button go in any of the clamshell Dells (and I've seen hundreds if not thousands of them), so that's unlikely to be the cause of your troubles.

As yyonline mentioned, I did see 4 Gb in Bios but not in the XP OS.

It's seeing all the ram then, but Windows is hitting the limit of 32-bit addressing.

[Raul]

Re: Help me identify blown component Dell 8400

Thank you yyonline for all your help!

[Raul]

Re: Help me identify blown component Dell 8400

An update. I replaced 6 capacitors on the motherboard and one in the power supply, I tried to replace the blown fuse but all I was getting was globs of solder (very tight space and the fuse is tiny, I didn't have brush on flux) so I left the fuse out, probably losing some of the USB ports. Computer still won't power up.

Tried to test the power supply by jump starting it, no success. I then tried the power supply of a Dell E310 on my Dell 8400, it powered up. Would not start Windows until I changed the SATA settings to ATA rather than the default AHCI.

The only thing that seemed bad in the power supply was one capacitor and I already replaced that one. Anyone repaired their PSU?

[Uranium-235]

Re: Help me identify blown component Dell 8400

unless they're some high quality power supply, they're usually not worth replacing caps. If its just a crappy dell PSU, better just to replace it with a fairly decent PSU

[momaka]

Re: Help me identify blown component Dell 8400

If its just a crappy dell PSU, better just to replace it with a fairly decent PSU

I strongly disagree with you here.
The standard Dell power supplies are OEM's usually made by Delta, Newton, Lite-On, and HiPro - all of these are very fine PSUs. Dell PSUs are good for a basic system and they will last nearly forever with good caps because they are well designed.

The only thing that seemed bad in the power supply was one capacitor and I already replaced that one. Anyone repaired their PSU?

If one is bad, the others may not be far behind. What was the brand of the failed capacitor? What are the brands/series of the other capacitors?
Post some internal pictures of the PSU. I usually find then worthwhile to fix.

[Raul]

Re: Help me identify blown component Dell 8400

The PSU capacitor that I replaced was a Ltec 1000uF10V. I used a Nichicon of the same value.
The other caps look fine and I can't even see their values unless I desolder them. From the colors, the capacitors look like Nichicons and a few more Ltecs, all with very flat tops, no bulging. I can't take a picture worth showing because it's so tight in there. I thought perhaps the fuse on the power supply fried so I tried to remove it and in the process shattered the ceramic body, the wire inside was not broken.
I do not want to buy another Dell PSU because a genuine Dell PSU is like $90. I am finding it very difficult to find a non Dell power supply that matches the values of this 350W power supply at a reasonable cost. I have to go to the 600-700W range on other brands (still cheaper) to get the 12V outputs to have 18A or better (the PSU has two 12V outputs). From what I read this is the most important thing to look for.
Am I correct to think that Dell puts a power supply that works fine for a bare bones system but once more cards are added the PSU is insufficient? (I added 2 video cards to run 3 additional monitors - my video cards have no fans - the computer is not used to play or watch movies, just stock charts with slow moving tick bars. I may be buying a used Xion 630 that I saw on Craigslist. It shows that the 12V outputs are 21 and 22A, more than the 18A that the Dell had. I could buy at a lower cost a PSU that does not have 18A (like 15A) on the 12V output but not sure if that would cause problems, I suppose if every component on the PC was running it could push power requirements higher but I read that most computers hardly ever do that.

[severach]

Re: Help me identify blown component Dell 8400

Is this a Lite-On supply? Do you have a LCD power supply tester? A power supply tester without the LCD screen isn't good enough.

I strongly disagree with you here.
The standard Dell power supplies are OEM's usually made by Delta, Newton, Lite-On, and HiPro - all of these are very fine PSUs. Dell PSUs are good for a basic system and they will last nearly forever with good caps because they are well designed.

Delta, Newton, and HiPro are fine. Lite-On is junk.

[Raul]

Re: Help me identify blown component Dell 8400

In between the heatsinks there are two transformers, printed on the larger one is: LITEON TL-130 0428 LC Rev. A. 42-M63111P01 HP OK
Anyone had any experience with the Xion brand? It is not listed in the list of PSUs to avoid.
I don't have a PSU tester.

[momaka]

Re: Help me identify blown component Dell 8400

The PSU capacitor that I replaced was a Ltec 1000uF10V. I used a Nichicon of the same value.

Just because the Nichicon capacitor has the same value does not mean it is adequate for that application.
There's two other specs besides the capacitance and voltage of a cap - ESR (equivalent series resistance) and ripple current, and they are actually quite important too.
To get those specs, you need to look up the series of the original capacitor. Each (not totally cheap) capacitor brand also has a 2 or 3 letter code written on it that indicates the series. For example, some of the more popular Rubycon series are MCZ, MBZ, ZL, ZLH, and YXG.
Once you find the series of each capacitor, you use that along with the brand name to find a datasheet on the internet. From the datasheet, you get the ESR and the ripple current specs for the capacitors you have. Finally, you use that info to find replacement caps that have the same or lower ESR and same or higher ripple current rating.
(or if this is way over your head, you can just ask here ).

The other caps look fine.

Doesn't necessarily mean they are. At a minimum, you should replace all of the L-tecs.

I can't take a picture worth showing because it's so tight in there.

Take it apart then.

I thought perhaps the fuse on the power supply fried so I tried to remove it and in the process shattered the ceramic body, the wire inside was not broken.

Get a multimeter and avoid having to do such guesswork. It takes all of 5 seconds to check a fuse with a multimeter.

I do not want to buy another Dell PSU because a genuine Dell PSU is like $90. I am finding it very difficult to find a non Dell power supply that matches the values of this 350W power supply at a reasonable cost.

If you're in the USA, you can often find cheap genuine OEM PSUs (Dell, Gateway, HP, etc.) on ebay and Hypermicro.

I have to go to the 600-700W range on other brands (still cheaper) to get the 12V outputs to have 18A or better (the PSU has two 12V outputs). From what I read this is the most important thing to look for.

Yes, but the brand of the PSU is also very important, though. Some manufacturers will print complete lies on the label.
With that said, I wouldn't really trust the Xion you talked about. I've seen cheap 450 Watt Xion PSUs for $10, and this makes me believe that they are not very reputable.

Am I correct to think that Dell puts a power supply that works fine for a bare bones system but once more cards are added the PSU is insufficient? (I added 2 video cards to run 3 additional monitors - my video cards have no fans...)

Depends on the video cards you used. Low to mid-range video cards that don't require an auxiliary power connector should be fine and won't likely overload the PSU, even under full load.

Is this a Lite-On supply? Do you have a LCD power supply tester? A power supply tester without the LCD screen isn't good enough.

Power supply testers are worthless. Don't waste your time with them. Short PS-ON (pin 14 on a 20 pin ATX connector, or pin 16 on a 24 pin ATX connector) to ground and measure voltage with a multimeter. It's still not a complete test, but it tells you a lot more than those "PSU testers" ever would.

Lite-On is junk.

Not the older Lite-On PSUs. But I guess that's not the case here, so you may be right.
I still prefer to see pics of the PSU, though, before I jump to conclusions.

[Raul]

Re: Help me identify blown component Dell 8400

I replaced the PSU capacitor with a much better one, with low ESR which is overkill for a PSU. Yes, I could have tested the fuse with a voltmeter and avoided breaking it, I wasn't thinking.
As I said before, the PSU could not be jump started. I would take apart the PSU but I don't have the equipment to test the components. I will buy a Corsair PSU and put and end to this. Thanks to all that replied.

[severach]

Re: Help me identify blown component Dell 8400

Power supply testers are worthless. Don't waste your time with them. Short PS-ON (pin 14 on a 20 pin ATX connector, or pin 16 on a 24 pin ATX connector) to ground and measure voltage with a multimeter. It's still not a complete test, but it tells you a lot more than those "PSU testers" ever would.

Apparently you haven't used the good PSU tester. Get the one with the LCD display. It does just what you said should be done with separate volt meters to each line and it measures the time for Power Good. The volt meters are good for fishing out bad supplies that seem to work but have voltages out of range.