Advice Wanted: I Have A Screw Loose In My Head-End...

Ha ha. But this is no joke.

As is my long standing superstition when building servers, I don't final torque every fastener until I try to boot the machine for the first time. I also don't even mess with any of those cheesy metal slot covers til all the hardware is showing AOK.

So after struggling a bit to cram 3 pci-e 16 cards, 7 drives, 5 fans and an oversized ps into a atx case, I booted the machine and checked that both bios and windows showed everything ok. Then as I was f'ing with one of those infernal alloy slot covers, the unthinkable happened:

Screw cam-out, followed by that sickening tinkling sound, known well to all who would dare build their own. With no exit sound. Ugh.

I don't know about you but I usually just try shaking the box a bit to get it out. But after applying 20 or so gentle tilting and tapping movements, I lost my cool and starting shaking the thing passionately. Could hear the screw moving but couldn't get it out. Then after a brisk movement or two the sound stopped altogether.

It probably came out, but it might not have. And I can't tell for sure because I have screws just like it all around the area... Shook it a bunch more, nothing. Looked everywhere I could see, nada.

So the question is how long do you mess around try to find where the screw is or went before deciding, f'it and just turning it on?

5 minutes? 15 minutes? Forever? Would you tear the whole thing down to the stand-offs before assuming it's OK?

Is there any trick to finding loose screws, high-power air or something, any ideas welcome.

But I don't think I can hold out much longer... Thanks.! :)

Depends on the value of the most expensive device that might fail vs the value of your time in hunting for it and the time the machine is down.

Me, I'd probably just turn it on.

Hi A,

The bad news is I think you should strip the PC apart as much as you can and check every nook and cranny to see if the screw has lodged firmly somewhere inside. I say this from a previous similar experience. Our company had just spent several thousand dollars on the latest PowerMac G5 at that time. A small screw dropped into the chassis as I was attempting to secure a PCI Express card. The computer was so heavy that I had a coworker help me lift it up and rotate, jiggle and shake the computer. The rattling sound stopped but no screw had dropped out. I was tempted to power it on on the basis that if the screw wasn't moving around, it wasn't going to dislodge and do any damage. However what if it was already lodged somewhere bad? On the flip side, what if I broke something while pulling all the innards out?

In the end, I felt too uncomfortable with powering on the computer in case the screw caused the computer to fry itself. I stripped the computer (no doubt voiding the warranty) and was rewarded by finding the screw wedged underneath the motherboard and in contact with solder points belonging to two electronic components. Had I turned on the computer, one or more components may have fried on the motherboard. This all took several hours to resolve but it paid off.

If you do decide to power it on without further investigation, try to plug the computer into a circuit that isn't going to affect anything else important in your building.

Sorry not to have an ingenious or fast suggestion for you. Good luck with this troubling problem and I hope other members may have some helpful tips to add to your screw thread.

Turn it on. If a blue flame does not shoot out from behind the motherboard you should be fine.

Combine what Luke has to say and what B says...all based on the expense of the system and how fast can you get another one ready.

Alternatively, if you have ESD safe place, you could minimize the potential damage by removing the things from the system that are not needed to power up.

For sure you can remove all the HDD, memory and cards in slots. The minimum parts are the PSU, mobo and CPU.

On some mobo, you can even remove the CPU (VERY CAREFULLY of course) and get about 2 seconds of power before the system decides that it can not continue.

When you are looking inside the system...look in and around the cable bundles since screws can get lodged in there as well as under the mobo as Luke mentioned.

Also look to see if there are any gaps in the chassis itself that are large enough to let a screw get caught up.

A DVM can sniff out a dead short in the power rails...but it wont find a short between pins on the mobo components.

After testing for dead short with DVM and with a trigger finger on the toggle and a low grade watt meter on the inlet, I turned it on and it it booted fine. Thanks everyone, and...

Last question, would you have any ethical problems selling this box now? Or do you tell them that that they might have a screw loose?

Hi A, that's good news. You must be relieved.

would you have any ethical problems selling this box now?

From an ethical point of view, if you do sell it, you would need to be prepared to honor the warranty and swap it out quickly and without expense to the customer if a problem occurred.

You may also wish to consider what impact a hardware failure might have on your business if the computer dies with the customer. Might it be better to use the machine for something else such as a demo model, QA test machine or a spare machine to help out customers who rapidly need to replace a dead VMS server?

Search for 1 minute per thousand dollars of equipment cost before closing your eyes, making a deal with any deity you identify with, plugging in to a good surge protector, and switching on.


Why do they make screws so damn conductive anyway?

Because non conductive screws are insanely expensive.


The screws are part of the chassis grounding solution. They conduct electricity and also bring two surfaces in contact with each other. This helps form a 'electrical shield' around the guts to help prepvent ESD damage and EMI radiation to name two big reasons.

That makes a lot of sense.

Sounds kinda like a Faraday cage:

Very much so. The chassis must represent the lowest impedance to ground.

Proper grounding of a complete system is often overlooked and a bad job leads to many issues.... AND they are the hardest to find and fix if you have them.

Brian wrote a nice report about this... Grounding and Bonding

One of my previous jobs was building custom PCs for the company I worked for at the time. We would build around a hundred or so a day with a few guys. We became pretty efficient in the way we staged them.

That said, I would have never left a floating screw in our cheapest $200 barebone. There is no way in hell I'm leaving one in a server. I would tear that thing back down until found.

On another note, my superstition begins and ends with the side panel. If you screw the side panel in place (either side) before posting the PC, you are sure to have a defective part somewhere. It is a law of Karma that most are unaware of.

Update: I just ordered one of these Karma 2.0 screwless cases, $50...

I might even put a side panel on before POSTing, just one though...

Looks decent for $50, but maybe just a little too much going on up front for my tastes. I like a little less gamer styling.

Our experince with screwless cases is that they do not ship well.

The HDD drives can easily get banged loose and sometimes break their plastic mounting pieces.

Ship the system with the HDD outside the chassis.

Two words: Big Magnet.

Three letters: MRI