Today my MNT reform seemed to have died while connected to power. It was running but not in use.
I noticed that all power seemed to be gone, the keyboard LCD dark and the firmware controller unresponsive to any input, so I disconnected wall power and battery, then reconnected it to wall power. Normally this will start the firmware controller and the MNT logo will show on the LCD but nothing happened.
While doing this, I noticed that the board was quite hot but the heat did mainly come from the “big cube” labeled with WE 220 right next to expansion board. Sorry, I know jack **** about electrical components, hope this description is sufficient ;).
It was so hot I burned my self a little on it. I decided, maybe the system needs to cool down a bit and I waited till it did but it made no difference.
Edit 2: The quoted section is not the issue, see bnys’s post below
While looking on the board for any trace off obvious damage that may cause the problem I discovered a oddity. R53 seems to not be correctly connected to both its pads. One side is soldered to R172 and the connection is really solide. This peace of the board has a light brownish tint and some residue on it. I think this could be a fabrication error but I’m not sure.
Emmc Image is reform system image V3, nvme image is V2
I had some thin plastic foam sheets between keyboard and main-board to dampen the sound of the keyboard. This may have hindered some heat dissipation.
If any of you or even @mntmn have an idea what the problem could be and if it is fixable I would be really happy to be able to resurrect my daily driver.
Edit: R53’s placement existed even before the first boot.
Oof, that’s not good. There are two possibilities:
The first is that R53 wasn’t properly soldered into place at the factory, and shifted so as to short out R172. That’d account for the failure and the burning - the “light brownish tint” you’ve noticed - but I wouldn’t have expected it to ever work.
The other is that something tried to put way too much current through R53, which made it get so hot it literally melted the solder and made it bond to R172 - you can see that it’s not just mechanically moved, it’s literally soldered to it.
It’s possible desoldering R53 and soldering it back into its rightful place would fix the former, if the burn hasn’t destroyed the PCB traces underneath and around the pads. If it wasn’t an assembly fault and was caused by excessive current, though, it’ll just happen again until the root cause is resolved.
Either way, I’d advise not using it for the moment - that looks like a fire hazard to me!
I checked some photos I made documenting the building of the DIY kit. And remarkably the issue is already present there. I will edit the original post to contain this info.
The cube shaped component labeled “WE 220” still gets really hot really quick when I connect power. After about 3 minutes it is hot enough that it hisses a bit when I touch it.
I pronounce this main-board dead. What a shame, it was so much fun
Hey, I’m sorry to hear about this. Which country are you in, perhaps in the EU? Then it might make sense to send us the board so we can take a look if it can be easily repaired.
If I’m not confusing cases with one another, the culprit is diode D5 which can fail to a short. Removing the diode will fix the system. According to the LTC4020 datasheet, it is optional.
I was migrating the V3 image to my nvme, when it all of the sudden it just died and got really warm where the “WE 220” thingy is locate. So I just pulled the plug, opened it up and removed the batteries. Looks like it melted the cable for the SYSCTL a tiny bit but no other visible damage.
I’ll see if I can remove diode D5 and hopefully that will fix it.
I had the laptop going last night compiling stuff when it switched off all of a sudden. I assumed it might have overheated but it switched back on immediately so I was happy. Turned it back off and left it only to find this morning it wont switch back on.
Applying power to the board make D8 & D9 switch on so it’s not completely dead, but the keyboard is unresponsive so I can’t switch it back on.
Managed to recover it.
Disconnecting and reconnecting sysctl cable while running off battries didn’t do anything. Connecting the charger and re-attempting it brought the keyboard back to life partially, displaying half the mnt logo and hanging there. Disconnecting and reconnecting the sysctl cable a third time while the charger was still connected recovered the keyboard and the menu loaded, allowing me to power the laptop up \o/
Perhaps connecting to the charger was unnecessary and it was the initial disconnection which helped (batteries are fully charged according to keyboard menu now).
Removing D5 didn’t seem to fix it. I got some sign of life though. It wakes up when only on batteries, but it doesn’t boot. It reports two of the batteries to be 2.7V and 0V. When I check them with a multimeter all report to be around 3.2V.
As soon as I plug in power it goes black and become unresponsive.
Only D8 lights up when power is plugged in. And only D11 lights up when trying to boot from batteries.
I’ll send an email to get the details on how and where I should send the board.
Just to make 100% sure, are the battery cables 100% plugged in all the way on the motherboard and on the battery boards? The symptoms sound like the voltage cannot be reliably measured and LPC turning off.
Transport and that sort should be no problem. I will write an email to shop at mntre dot com for the details?
I got some sign of life though. 
It wakes up when only on batteries, but it doesn’t boot. It reports two of the batteries to be 2.7V and 0V. When I check them with a multimeter all report to be around 3.2V.