Curious Case of OptiPlex Button...

[PliotronX]

I have never encountered something like this so I was wondering if you guys also thought the power supply sounded like the culprit.

Subject is a Dell OptiPlex 7040 built Q4 2015 - coworker was using it with few troubles up until a few weeks ago when he quit so I traded up from a 3020. I had added a USB 3.0 PCI-E card, three sticks of additional 8GB DDR4-2133 and a mechanical drive (only other notable component is a Radeon 350 stock) and they were working fine. The trouble started when I installed an m.2 SATA drive to the motherboard socket. When the power supply was merely plugged in, there was an odor that smelled familiar. Checking for metal contact and not seeing any, I reseated most components for good measure. Plugging it back in, I saw the ghost in the form of white smoke rising from the case. An ordinarily black ICC on the board is now white. The thing was dead as a doornail. Awaiting a replacement of the motherboard, I got a 2.5" adapter/enclosure for the m.2 to test with another machine - no problem. Following the motherboard replacement, again, no problems for almost two weeks with everything including the m.2 drive in the SATA adapter.

Now for the event leading me to question the PSU - Monday morning the system was completely off and unresponsive. I removed all extraneous components fearing the worst and it still refused to power on. This time, I don't see any burned chips but a polymer capacitor is bulging in the middle of the motherboard. I tried everything from past experience, including the flea power drainage. Tech support recommended this step first thing and of course it coaxes the system to boot while on the phone. Passes extended diagnostics. Case closed.

(note - the 3020 and this 7040 are using a battery backup with zero issues with any device ever plugged into it in the past)

My theory is that the power supply is insufficient and pushed over the edge by the additional components. I have an ATX power supply with better amperages and efficiency on the way with an adapter for the header but my real question:

tl;dr - can an anemic power supply with dual rails fry components on the motherboard without damaging anything else in the system?

Dell sure doesn't make them like they used to - I worked on an OptiPlex 760 that survived an office fire, the entire chassis charred but the system runs like a champ.

 

[VirtualLarry]

Is this a business work system? Or a home system, based on a re-purposed office desktop model? If it's a business rig, let support take care of it. (Unless, you ARE "support".)

 

[VirtualLarry]

I don't know exactly, but it doesn't seem impossible that a too-weak PSU might be stressed to the point of not being able to reliably supply power at a regulated voltage level, thus killing components.

Who is the actual PSU mfg? Years ago, they used to be Lite-On or Delta, and those were pretty solid, albeit kind of lean.

 

[PliotronX]

Is this a business work system? Or a home system, based on a re-purposed office desktop model? If it's a business rig, let support take care of it. (Unless, you ARE "support".)

I don't know exactly, but it doesn't seem impossible that a too-weak PSU might be stressed to the point of not being able to reliably supply power at a regulated voltage level, thus killing components.

Who is the actual PSU mfg? Years ago, they used to be Lite-On or Delta, and those were pretty solid, albeit kind of lean.

It's an office system and the head honchoes won't let me BYOD I work at an MSP but since we all have to use Dell, their support is what we rely on for our own systems (I guess surgeons really do have to go to other surgeons ) but this is the cause for my concern. I know it's going to keep failing but when it performs the diagnostics intermittently fine, Dell will keep closing the case. They are sometimes difficult to work with. Boy the lady I got when I called in for the fried ICC was trying every trick to say it was something other than the board and if the dispatch found user-induced damage we'd be financially responsible for the replacement.

The PSU is Acbel Electronic (WUHAN) and is 270W. The power supply I will be using with an ATX-to-Dell adapter is a Seasonic S12II 620W which will be grounded to the chassis with ring terminals and run external to the chassis.

It's a giant PITA when this thing goes offline because we do not have a spare to await service, I have to use an Optiplex 380 that I popped an E8500 into and it can barely hang with Skype for Business and all the junk I do daily and only supports one monitor.... one monitor makes Jack angry.