My MNT Reform suddenly smoked and shut down

MNT Reform
1

I was happily using my MNT when it suddenly shut down and a white wisp of magic smoke escaped from near the power plug and there was an unpleasant burning smell.

MNT_burrnt
MNT_burrnt1920×1878 465 KB

Taking it apart, I found that resistors R53 and R172 were surrounded by burnt flux.

Looking at the schematics, R172 seems to be RC0603FR-0710KL, but I can’t find R53. Is my board an obsolete revision? How do I find out what R53 is? How hard is it to replace surface-mounted components? Is it worth upgrading to the latest board revision, and is it available anywhere?

Any advice would be appreciated!

Thanks!

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Hi, that looks like motherboard MREFPMOB20R02 aka motherboard 2.0. The diagonal resistor is intentional. It was an early motherboard fix. So this directory should include the schematics for your board: reform2-motherboard-pcb · master · Reform / reform · GitLab

Unfortunately, I cannot help you more as I’m not a hardware person. Is your device still within its warranty period? @minute might be the best person to give a good answer here.

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From your link I was able to find that R53 is RC0603FR-07330RL.

My device is from 2022 so it’s out of warranty, unfortunately.

I’ll ask around at my local makerspace for soldering advice.

Thank you!

4

From the image, it looks like D5 is likely what burned out. Depending on the flux or solder used when soldering the factory bodge for the resistors (the diagonal resistor) it might look that way due to age or due to them getting hot, but D5 (RBR3MM60ATF) definitely looks like it would need to be replaced.

2 Likes
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Oh wow, I stared at that photo for a long time and did not notice the small blip on D5!

Yes, D5 is apparently a known offender:

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Good eyes! I’m going to replace all 3 (D5, R53, R172) just in case.