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I got a Dell AIO that was reported "not working properly". It showed different odd behavior initially, but that settled quickly into even more broken.
The monitor part is functional, as I can use its menu, but the computer part seems dead (similar reports here).

On turn on the fans spin seemingly at max speed, and stay there. There's no Dell boot logo, no beeps, nothing.

I've disconnected the optical drive, HDD, and WLAN card, and tried each SODIMM separately in both slots.
The behavior stays the same.

Any ideas?

meerkt wrote:

I got a Dell AIO. The monitor part is functional but the computer part seems dead. Any ideas?

This is exactly the reason that All-in-One computers are a terrible idea.

Dell support would probably ship you a replacement motherboard.

Yeah, not a fan of AIOs and I wouldn't get one myself. But I don't think reliability should be inherently much different than laptops.

It could be the mobo, but I wonder if also something else. Maybe the PSU even though it looks fine, or one of the small sub-boards, or maybe even the CPU just needs new thermal paste or reseating. Maybe it's partly a firmware bug and there's a secret jumper to reset it.

Just not sure how to narrow it down and thought someone had experience with these. It's out of warranty. If I can arrive at a good guess, at best I might try some used part off eBay. Maybe.

BTW, this is the mobo (from eBay):

Replace the battery and clear the CMOS (there's likely a jumper somewhere). While no guarantee to fix things, you would be surprised how many times that will address a machine that exhibits very odd boot issues, especially if the machine is a few years old. It's cheap too.

--SS

Definitely sounds like something went bad with the BIOS. When the fans go full throttle it seems it no longer has a brain to detect temps. It might be worth if its easy and cheap enough to find a replacement BIOS chip replacement to try out if the CMOS flush doesn't work. Make sure to unplug it and hold the power button down for a few minutes too to clear out bad stuff.

Agree on CMOS, also check for bad caps.

CMOS clear didn't help, nor a different coin battery.

The BIOS flash isn't a socketed chip as far as I can tell.

Caps look okay visually. The ones next to the CPU are polymer electrolytics so probably fine after 3 years.

It looks like from that Ebay motherboard that it has a VGA out. It might be a shot in the dark but try an external monitor on it and see if anything shows up to help you troubleshoot. It might be worth trying to then disconnect the integrated video cable if for some reason that's causing a low power fault in some way.

VGA out: nothing shown (I didn't disconnect the internal video; the connectors are flimsy and I didn't want to mess with it too much).

And it's actually more dysfunctional than expected. I thought it would work as a monitor because the input selection menu works. But in fact, no. Both HDMI and VGA inputs state on-screen that there's no signal. Interestingly, with HDMI the external computer does identify the AIO properly as a monitor with the right resolution.

I think it's about ready to be declared officially dead.

Any final ideas, or just proceed to component scrounging?

Yeah when fans just spin up like that, it means it isn't reaching POST. So you checked the RAM already, you need to confirm video (which is on CPU so you can't) and then CPU. You can confirm 100% again that it isn't posting one of the three required hardware components. CPU, RAM, Video and of course if the motherboard isn't let those work it goes without saying. Disconnect the HDD or SSD boot up and let it spin for 30 or so seconds like it would be getting into windows and then just push the power button. If it turns of immediately when you push it, you are posting but getting no image on screen. A system that doesn't post wont respond to a single press of a power button and needs to have it held down to hard shut down.

Since I've never seen a CPU die, if it were the CPU it could really only be from overheating from bad thermal grease to heat sink marriage. I'd check to see if that is an issue. If you removed the motherboard already, you can check the pins on the LGA to make sure none of those turned color from overheating. I had an old Pentium D AIO system in a dental office years ago where the little fan cooling the CPU wasn't nearly enough. It didn't thermally shut itself down but somehow the LGA pins blued from the heat over and made a bad connection. It's not very likely but just inspect them for any damage, ect. Chances are it is just a motherboard that flaked out due to a bad trace, a sub-par component on the motherboard or something along those lines.

A suggestion, seriously avoid AIO at all cost, because that is exactly what they will do, cost you. I've had way to many fail and they were "Medical Grade" units from these guys.
https://www.cybernetman.com/ We had to replace so many motherboards, and LCD power boards I could cry. Still have some of the little boards they use to provide their LCDs power where the cheapo capacitors died. We did our own in-house repair on those with good capacitors from Badcaps.net

EDIT: OHhh one last thing to look for, see if any of the USB ports have the plastic center broken off and possibly crossing the USB leads. I've had system that do what you are talking about due to a short from USB ports when they break. It's a lot more common than you think. Especially when a user shoves a USB drive into the new USB 4th position!

Briefly pressing the power button 30 seconds after power on usually does nothing. But I don't know, maybe this is the normal behavior. I don't think these non-standard PCs usually turn off after a quick press? In one case, though, it turned off the monitor's backlight. It may have been after two short presses rather than one, but I couldn't reproduce it.

USB ports looks physically fine. Removing the CPU cooler is too much of a hassle.

I didn't buy this AIO, just got it for an analysis. I don't think this form factor is a good idea, but still I'm underwhelmed with its reliability and fixability.

Everyone, thanks for the suggestions.

Anyway, I took out the HDD to at least get the data. Turns out also by itself the HDD is behaving strangely...

If you press the power button before any OS loads it should shut down immediately if it has all of the required hardware to POST properly.

Yeah, sounds like you've tested most everything. The screen shutting off separately doesn't mean much other than their screen power and system power prospely aren't communicating with each other which lends to the theory that the board isn't passing POST, no surprise.

Good luck man, hope it all works out fine.

meerkt wrote:

Briefly pressing the power button 30 seconds after power on usually does nothing. But I don't know, maybe this is the normal behavior. I don't think these non-standard PCs usually turn off after a quick press? In one case, though, it turned off the monitor's backlight. It may have been after two short presses rather than one, but I couldn't reproduce it.

USB ports looks physically fine. Removing the CPU cooler is too much of a hassle.

I didn't buy this AIO, just got it for an analysis. I don't think this form factor is a good idea, but still I'm underwhelmed with its reliability and fixability.

Everyone, thanks for the suggestions.

Anyway, I took out the HDD to at least get the data. Turns out also by itself the HDD is behaving strangely...

First thing I always suspect in these things is PSU section-could be on separate board or even part on separate board,part on MB.
If that is the problem,and on separate board could be cheap to fix.
These things tend to have the equivalent to a $5 PSU.
And I always stress-PSU IS THE MOST IMPORTANT PART OF ANY BUILD.............
good luck

The PSU at least powers up the monitor and drives, but I haven't checked voltages.
I've given up on the computer. Now just copying the data off the bad HDD. Sslloowwllyy.

The PSU looks like this: