Intel NUC DC53427HYE no power (schematic help ?) - Page 1
Forum section: electronics / repair

author: Dannyx
author_rank: Regular Contributor
timestamp: April 02, 2025, 05:43:29 am
content: Good day everyone. A friend of mine gave me a couple of these small Intel NUCs to take a look at and see if I can get them going. The model of the board itself is D53427RKE They both behave roughly the same: when I plug in the power jack, the blue power LED comes on straight away, but that's it - the fan doesn't spin and it draws zero current from my bench supply. If I try to hit the power button, the LED goes off....ironic AF. If I press it again, the LED comes on for like half a second and goes off. Sometimes it tries this cycle multiple times on its own, before eventually giving up and staying off. The fan never spins and never draws any current......The thermal camera doesn't reveal anything out of the ordinary, which is to be expected since it doesn't consume any power, so I don't know where to look. It could be any number of things: a bad BIOS (which I couldn't find a dump of), a bad component or a bad solder ball under the CPU or GPU (?)....I took some measurements and the 3.3v and 5v stand-by rails are present (also confirmed by a green LED which stays on). When I hit the power button, other rails appear to come on for a brief moment, but don't STAY on, so there could be a short somewhere. I didn't find anything dead-shorted when buzzing around with DMM on the larger components like inductors and caps. Even the CPU shows like 3. something Ohms.I also find it strange that the power LED comes on as soon as I plug in the power - it could be indicative of a bad "system controller" (?). It reacts to the power button in some way, but doesn't make sense...Does anyone happen to have a schematic or a boardview for this ? It would be really handy. Cheers.

author: Swake
author_rank: Frequent Contributor
timestamp: April 06, 2025, 11:50:07 am
content: In the second picture on the bottom left I believe there are traces of dried up liquid. Might have some damage in that area or caused by that liquid.The 6 pin chip in that corner looks scratched or even damaged, or maybe nothing, but worth checking.I can see some dirt/traces of something on the bottom right too.Well... it is everywhere actually. On the top right there is whatever that stuff is on a couple capacitors and a chip.Anyhow, you'll have to clean that board up good before you can continue deeper research.Double check the switch, might be sticky or something.

author: temperance
author_rank: Super Contributor
timestamp: April 06, 2025, 01:30:29 pm
content: The processor or video die might be damaged. It is easy to damage those when attaching/removing the heat sink. (Some Unfortunate real life experience when I killed my two months old pretty expensive P III looong ago when I wanted to install a larger heat sink with a quit fan.)

author: Dannyx
author_rank: Regular Contributor
timestamp: April 06, 2025, 03:37:40 pm
content: I wouldn't worry about what appears to be traces of liquid - it's not, probably just flux residue. Besides, it's highly unlikely BOTH NUCs the chap gave me suffered from liquid damage AND exhibit the same exact behavior.For curiosity's sake, I took off the BIOS chip entirely and tried powering up the board without it....probably a useless thing to try, but I wanted to see what would happen. Surprisingly, the power LED no longer came on immediately when I plugged in the power, but instead when I hit the power button. Of course, nothing else happened (no Vcore), which made perfect sense with no BIOS chip on there, so this got me thinking maybe it IS the BIOS after all....nothing to lose, right ? This is where I got stuck, because I could not find a dump for this board. The only thing I WAS able to find was a bios UPGRADE file (.bio format), but that wasn't much help, since you're supposed to put it on a USB drive and load it once the system has powered up......which obviously doesn't happen.I then tried a more radical approach and tried heating up the chips with hot air, again, just to see if there's any change in behavior at all. When the chips were still hot, the power LED no longer came on AT ALL, since there's most likely a temperature sensor on there which prevents the board from coming on when it's too hot. As soon as it cooled down to a more tolerable temperature, pressing the power button did cause the fan to start spinning and I got some voltages on some of the black capacitors around the chips (probably "VTT" ?), but still no Vcore and no picture. When it cooled down even further, it went back to the original state: power LED comes on as soon as the DC jack is inserted and pressing the power button briefly cycles the LED on and off, but nothing more - no fan spin and no Vcore. I think at this stage either the CPU or the other chip (PCH probably ?) might be dead or has dried solder balls underneath, as I haven't used flux to try a proper reflow - just a quick once-over with the hot air station set to 400c from pretty far away.

author: Swake
author_rank: Frequent Contributor
timestamp: April 07, 2025, 06:52:02 pm
content: Compare the 2 BIOS chips. Even if these chip are dying, it would be surprising for them to fail in the same spot. Unless it was a failed firmware upgrade, resulting in a bricked NUC.Does your friend has 3rd working NUC? Could copy the BIOS from that one.

author: Dannyx
author_rank: Regular Contributor
timestamp: April 07, 2025, 07:38:55 pm
content: He said he'll try sourcing one, but it's not certain, that's why I tried finding a BIN.