shorted PB5 & VBB need help

Question

discip opened this issue 2 years ago · comments

So, as mentioned in the title, I managed to short out one of the WPM fan outputs.

Now I need to find out what got corrupted.

Is anyone willing to help me diagnose if the MCU is fried or if I just need to replace some resistors, capacitors or something?

Additional information:
I tried powering the board from both DCIN and USB.
In both cases the connected display shows no printer attached.

Inserting an SD card with a frimware.bin leaves the mentioned file untouched.

The green LED next to the fan output that I shorted out is on because the corresponding transistor is also fried.

This is what it looks like when powered up:

thanks in advance
kind regards

Radek · Answer 1 · Wed Oct 05 2022 04:40:57 GMT+0800 (China Standard Time)

Check fuse F2 (10A), transistor Q2 and transistor Q10

discip · Answer 2 · Wed Oct 05 2022 04:45:14 GMT+0800 (China Standard Time)

@radek8
Thank you for the quick reply!

F2 is ok!

Q10 is fried as mentioned above.

Q2: Judging by this results: Is it dead?

Radek · Answer 3 · Wed Oct 05 2022 05:22:55 GMT+0800 (China Standard Time)

If you connect the board to the computer via USB, does it communicate with the computer?

discip · Answer 4 · Wed Oct 05 2022 05:27:13 GMT+0800 (China Standard Time)

No it does not!

Radek · Answer 5 · Wed Oct 05 2022 13:22:33 GMT+0800 (China Standard Time)

Check fuse F1 (T300-4A)
If it is OK and there is 3.3V power on the wifi connector
So the processor will be burnt.

Radek · Answer 6 · Wed Oct 05 2022 13:33:05 GMT+0800 (China Standard Time)

2 red LEDs are on, so the 3.3V power supply will be fine.
Looks like a faulty MCU :-(

discip · Answer 7 · Wed Oct 05 2022 13:54:10 GMT+0800 (China Standard Time)

Thanks for the effort.

Have a nice day. 🙂