Power supply issues

Hey everyone. I’ve got an HP EliteDesk 800 G6 that’s about a year and a half old, and I’m running into some weird power issues. It’s happened two or three times now...

Basically, whenever I try to boot up the computer, the power button light just flashes a couple of times and then dies. If you look at the Dell documentation, they suggest it might be a faulty power cable. Well, I swapped out the cable and everything seemed fine for maybe three or four days—until two days ago. I tried another cable (I had a few spares lying around), but the next day when I went to turn it on, I ran into the exact same issue. Since the power strip I was using was pretty old, I decided to grab a brand-new one, but even with a fresh strip, nothing changed.

I finally figured something out this morning: if I unplug the power cord from the power supply itself, wait about 10 seconds until the blinking stops, and then plug it back in, the PC actually boots up fine. But once I shut it down again, I have to repeat that whole little ritual. What used to be an occasional glitch has turned into a mandatory step every single time I want to use my PC.

Any idea what’s going on here? Is it a loose connection in the power supply unit, or something else entirely? 😵

Based on what you're saying, the power supply sounds like the culprit (probably some blown electrolytic capacitors).
If it's still under warranty, I'd just take it back to the shop and have them ship it off to an authorized Dell service center.

wearymason4 said:Based on the symptoms, the power supply seems to be the culprit—likely some failing electrolytic capacitors.
If it’s still under warranty, I'd take it back to the retailer and have them send it off to an authorized Dell service center.

Actually, it wasn't that—I just figured it out. Swapped out the CMOS battery and now everything is running perfectly. 🙏

I was checking the warranty online, and it looks like this PC sat untouched in the US from July 2020 until July 2021. Then, the previous owner bought it for his company on July 23, 2021. When I picked it up from him in February 2022, it had Windows and Office pre-installed and was practically spotless—it honestly smelled brand new. So, the machine was essentially covered by warranty and sat idle for nearly a year and a half before I even touched it. I'm not entirely sure if that long period of sitting around actually matters or not.

So, was the culprit just the CMOS battery on the motherboard? That little coin cell thing?

It’s possible that if a battery isn't getting any juice for like 6 to 12 months, it could be totally fried, though you don't see that happening all that often these days. Usually, those things last about 3 to 7 years before they give up the ghost.

Jack Cook7 said:So the issue was just the motherboard CMOS battery? That little coin cell?

Could be. If a battery sits dead for 6-12 months, it might be toast, though that’s pretty rare nowadays. Usually, they last about 3 to 7 years.

And those batteries don't "recharge"—they just die when they die. Maybe something was pulling a tiny bit of juice from it.

It’s entirely possible that battery will fail again in a year or so. I’ve had PCs where the battery lasts a year or two, and others where it stays good for 5+ years. It's not random; you really do end up swapping them multiple times over the life of the same PC.

Whatever. Just buy a pack of them and swap it out every few years.

Or maybe the battery was just straight-up garbage and now everything's fine.

wiredotter14 said:those batteries don't actually recharge—they just last as long as they last—though it's possible something was draining a tiny bit of juice

It’s entirely plausible that the battery might fail again in a year or so. I've had PCs where the battery lasts maybe a year or two, and others where it holds up for five-plus years—it's certainly not a coincidence if you find yourself swapping out multiple batteries over the course of a single PC's lifespan.

Honestly, you just buy a pack of them and swap one out every few years.

Or, the battery was simply garbage to begin with, and now everything should be fine.

To be honest, I have no idea and it's driving me absolutely crazy... So, for two days, everything seemed fine, but now, every single time I try to start my PC—I have to unplug the cable and plug it back in, and every time, it boots straight into the BIOS... I tried resetting to factory settings and using "last known good settings," but nothing works; it just keeps kicking me back to the BIOS at startup. Yesterday, I popped in a battery I grabbed from Walmart, then thought maybe that wasn't it, so today I tried an Energizer, but still nothing.

Look, once you're back in the BIOS after swapping out that battery, you've gotta go in and dial everything back in—start with fixing the date and time, then hit all the other settings... just make sure you save your changes before you exit.

wearymason4 said:Well, once you're back in the BIOS after swapping out the battery, you really need to go through and reset all your settings—starting with the date and time, then everything else—and make sure to save those changes before you exit.

I've tried entering the date and time a few times now, but I keep hitting this "invalid configuration information" error—honestly, I'm at a bit of a loss as to where to go from here...

wearymason4 said:Once you're in the BIOS after swapping out the battery, you really need to go through and recalibrate all your settings—starting with the date and time, then everything else—and make sure to save those changes before you exit.

I’ve been using hibernation to shut it down, but I'm running into a weird loop. If I hibernate it for just a short bit, it boots up fine—but if it sits in hibernation for a few hours or overnight, the same headache happens: it kicks me straight into the BIOS, even though it technically resumes from the hibernation state.

The folks over at Dell support mentioned that they might require an original receipt to process anything, which I unfortunately don't have—all I have left is the warranty info. Because of that, I'm thinking about picking up a new power supply just to see if that's actually the culprit. The tricky part is that the connectors on the Dell OptiPlex 7070 aren't like what you'd find in a standard PC. The PSU I currently have on hand only has two connectors—a 4-pin and a 6-pin. I was planning on grabbing this one—the Dell Power Supply—just as a test run to see if a faulty power supply is what's causing the glitch.

It’s not gonna work, at least not unless you’re planning on soldering and hacking through some cables.

Just toggle between UEFI or legacy boot. You probably have one selected when it’s actually set to the other, so it won't boot.

Why on earth do you think the power supply is the issue?

wiredotter14 said:Why do you think the power supply is the culprit?

To be honest, I’m a bit stuck—once I actually get it powered up, everything seems to run perfectly fine. But the advice I'm getting is all over the place; some people are pointing toward the power supply, others are suggesting the motherboard might be the culprit, and then there's the argument that it's a BIOS issue. It's hard to know which direction to take when everyone has a different theory.

So, I gave it a shot—tried digging through the setupact.log to see if I could track down that "Detected boot environment" entry.
I’m stumped. I honestly don't get it—in the BIOS, everything looks perfectly fine; UEFI is enabled and the SSD containing my Windows installation is correctly flagged, so on paper, there shouldn't be an issue at all. However, once I shut the PC down, I can't seem to get it to boot back up normally. The only way around it is to completely kill the power at the wall, plug it back in, and try again—but even then, the behavior is bizarre. It's like the power supply reacts strangely—I know that much for sure—and sometimes it’ll stay powered on for about a minute before just cutting out entirely, or occasionally it'll trigger a reboot on its own, even though I haven't set it to do that.

You know? I’m a total novice here—I get the basics, sure, but not nearly enough to feel confident—and honestly, this whole situation is driving me absolutely up the wall. 😵

As they’ve already pointed out to you, the core issue is most likely a failing electrolytic capacitor in the power supply (or perhaps one feeding the MOSFET gate) that occasionally fails to provide enough conductivity to sustain the startup sequence while under voltage. This explains why it suddenly works once you unplug the power cord after a failed attempt. It is also possible that the standard US wall outlet or plug has a loose connection, though I doubt the cable itself is the culprit.
Furthermore, it is quite common for electronic circuits to experience momentary glitches due to various factors, preventing transient states from executing correctly.

Next time, try leaving the unit completely disconnected from the power source—ensure it isn't even in standby mode—for several hours or even overnight. This allows any parasitic capacitance within the components to fully discharge. Once you've done that, let me know if it behaves properly again.

Jerry Robinson56 said:Like they mentioned, the core issue is most likely an electrolytic capacitor in the power supply—or perhaps the one feeding the MOSFET gate—that occasionally fails to provide enough conductivity to sustain the startup sequence while under voltage. That would explain why it works fine after you unplug the power cord and plug it back in. It’s also possible there's a weak contact in the standard US wall outlet (120V), though I doubt it's the cable itself.
Plus, it's pretty common for electronic circuits to occasionally "glitch out" due to various factors, causing transient states to fail to resolve properly.

Try leaving it completely disconnected from the wall—not just in standby mode—for a few hours or even overnight. This allows any parasitic capacitance within the components to fully discharge. Let me know if it behaves once you try again.

Thanks... So, I left it unplugged for about four and a half hours total. When I turn it back on, it does the exact same thing—it boots straight into the BIOS. If I shut it down, it won't start up again; the indicator light just blinks (a 2 + 1 pattern).

Patrick Sanchez84 said:Thanks... so I ran it for a total of 4.5 hours without any network connection. Upon restarting, it demands the exact same thing, throwing me straight into the BIOS. Once I shut it down, it refuses to start again; the indicator light just blinks (2 + 1).

This is a new development, or at least I haven't come across it in my reading before,

So, it’s prompting you to press something like F1 to enter the BIOS?

Try replacing the CMOS battery on the motherboard.

Also, take a look at the motherboard to see if there are any bulging or slightly lifted capacitor casings (those silver components with the blue circular tops). However, it would be much simpler to try swapping out the power supply—you could probably borrow one from someone since they are compatible, provided you ensure the wattage is sufficient.

The Dell OptiPlex 7070 SFF comes with a 200 Watt PSU. That is also problematic; it is quite easy to lose some effective power, which results in these exact same symptoms.



The vast majority of failures are mechanical in nature—faulty contacts, typically—but occasionally it is a combination of factors. Based on your description, though, capacitors are almost certainly involved in this phenomenon. Whether it is unstable voltage on the board itself or an issue originating from the power supply, that seems to be the root cause. You should also try unplugging the power connector on the motherboard and reseating it firmly. I dealt with a case once where a single pin had a poor connection, which ended up blackening the connector and carbonizing the wire.

Here’s the service manual for your PC:

https://www.dell.com/support/home/en...0-desktop/docs

On page 94, there's troubleshooting for that specific error code (2 amber lights and 1 white). It suggests something might be wrong with the motherboard.

One thing you could try is updating the BIOS:

https://www.dell.com/support/home/en...x-7070-desktop

(Just a heads up—read the note saying if your BIOS is older than 1.3.1, you gotta hit 1.3.1 first before jumping to 1.5.0 or anything newer.)

And my own little disclaimer—if the motherboard totally dies on you, don't come blaming me.😬

If that doesn't work, maybe try updating some firmware (like the network card, SSD, or TPM module):

https://www.dell.com/support/home/en...esktop/drivers

(You can just pick the firmware from there).

Lastly, if nothing works and you're out of warranty, buying random parts for this PC is probably a waste since they're pretty niche. There's a solid electronics repair shop in Seattle that does component-level work if you need it:

http://www.itelektronika.com

Jerry Robinson56 said:This is news to me—I don't recall seeing this mentioned before, or perhaps I just missed it,

So, does it actually prompt you to hit something like F1 to enter the BIOS?

Your best bet might be swapping out the CMOS battery on the motherboard.

Also, take a close look at the board itself; check if any capacitors—those little silver cylinders with the blue tops—look bulged or slightly lifted. Honestly, though, it might be much easier to just try a different power supply. You could borrow one from a friend since they're generally compatible, provided you make sure the wattage is sufficient.

The Dell OptiPlex 7070 SFF comes with a 200 Watt PSU. That’s also a weak point—it's easy to lose some effective output, which leads to these exact kinds of symptoms.



Most hardware failures end up being mechanical issues—bad connections, for instance—but sometimes it’s a combination of factors. Based on what you're describing, I'd bet my money on the capacitors. Whether it's an issue on the board itself or a shaky power supply, that seems to be the culprit. Also, try unplugging the power connector on the motherboard and seating it firmly again. I dealt with a case once where a single pin had a poor connection—the connector actually turned black from the wire carbonizing.

Thnx for the advice...

I actually swapped the battery three times in just two days. First, I threw in one from Walmart, which seemed fine for a day, but then the same issue popped up, so I went with a brand-new one since that Walmart one had been sitting on the shelf for a while... but no luck there either.

I’ve gone over the board with a magnifying glass, and nothing looks bulged. I already tried messing with the connectors at the start—unplugged everything and reseated them—but they look perfectly fine. I even pulled the RAM, moved it around, and tried again, but nothing works. I'm honestly running out of things to try besides swapping the power supply, but this Dell unit is a bit tricky because of its proprietary cable setup—it uses those 4 and 6-pin configurations. A buddy lent me two working power supplies, but they were both standard units with the usual 4-pin connectors. My only real option now is to hunt down some adapters to make those 500W units work with this machine.

As for the BIOS, it doesn't give me a prompt to enter it; it just boots straight into two error messages... something about "time and date setup" plus "invalid configuration information"...

Patrick Sanchez84 As follows:
Thnx for the advice.

I have gone through the ordeal of replacing the battery three times in just two days. Initially, I opted for a budget option from Walmart; it seemed functional enough for about twenty-four hours, but by the second day, the exact same failure recurred. I subsequently installed an entirely new unit, reasoning that the Walmart battery had likely been sitting on a shelf far too long. Even then, there was absolutely nothing to show for it. No improvement whatsoever.

I’ve inspected the motherboard under magnification, and I can confirm there isn't a single bloated capacitor in sight. I even went back to basics early on by disconnecting all the connectors to rule out any shorts—nothing. The connectors themselves look perfectly fine. I tried reseating the RAM, moving it around, testing different slots... absolutely nothing works. At this point, I feel like I've exhausted every standard troubleshooting step short of swapping the power supply entirely. However, dealing with this specific Dell unit is proving to be a nuisance. It uses a proprietary setup with those dual 4-pin and 6-pin connectors. A friend of mine lent me two functional power supplies, but they are both standard ATX units with only the basic 4-pin connector. My only real recourse now is to track down or purchase some adapters to bridge the gap between those 500W units and this specific Dell configuration. It's an unnecessary hurdle, frankly.

It doesn't even give me the option to enter the BIOS manually. It just forces its way in and hits me with two error messages before I can do anything about it. I find myself once again staring at an interface that refuses to cooperate. It seems we have encountered a recurring nuisance regarding the time and date setup, coupled with what the system describes as "invalid configuration information." It is a tedious loop. One attempts to synchronize the clock, only to be met with a digital shrug and a notification that the settings provided are somehow fundamentally flawed. It is quite tiresome when the hardware insists on being more difficult than necessary. I shall continue to investigate this inconsistency, though I suspect it will be a long afternoon of troubleshooting...

This is a definitive indication that something is malfunctioning with the CMOS battery within the BIOS. It could be anything from a loose connection in the battery socket to the simple fact that the old batteries have finally reached the end of their lifespan.
It must maintain a voltage higher than 3.2V—though, if I’m being honest, it might still hold steady at 3.0V. Of course, there remains the possibility that the motherboard is at fault, though I wouldn't go so far as to bet on that being the primary issue.
In the BIOS, you typically have the option to manually read the battery voltage yourself.
Is it shutting down on you, or is it performing a full system reset while you're actually in the middle of working? And regarding that message it threw at you... what exactly did it say? fadedorca66 One must exercise extreme caution during a BIOS flash to ensure you don't inadvertently brick the machine entirely. It is an unforgiving process. You absolutely need a reliable power supply to guarantee stability throughout the update; anything less is simply asking for disaster. 😁

fadedorca66 said:Here is the service manual for your PC:

https://www.dell.com/support/home/en...0-desktop/docs

If you look at page 94, there's a troubleshooting section for that specific error code (2 amber flashes followed by 1 white)—it suggests there might be an issue with the motherboard.

It’s just blinking 2+1, but both are amber.

One thing you could try—just as a long shot—is updating the BIOS:

https://www.dell.com/support/home/en...x-7070-desktop

(Make sure to read the note: "If your system BIOS version is earlier than 1.3.1, ensure that you update the BIOS to version 1.3.1 before updating to version 1.5.0 or later.")

My system is completely up to date; I'm running BIOS version 1.20.

Just a quick heads-up from my side—if the motherboard ends up failing completely, don't come blaming me! 😬

😁

If that doesn't do the trick, you could attempt to update various firmware components—things like the network card, the SSD, or the TPM module:

https://www.dell.com/support/home/en...esktop/drivers

(You'll need to select the firmware category).

Finally, if none of this works and you're out of warranty, buying random parts for this machine doesn't make much sense—they're pretty specific and can be hard to track down. You might want to check out a local specialist; there's a great electronics repair shop in San Francisco that does component-level work:

http://www.itelektronika.com

Thanks, I'll see what else I can try... I think I'll reach out to Dell support directly.