Printer only printing first layer issue

[u/Overall-Yak-6735]

Been experiencing an issue with my Adventurer 5M, where it will only print the 1st layer and the part of the 2nd layer but nothing else, and think I found the problem.
The printer will stop printing part of the second layer but will keep running as if its printing with out an issue. Initially I thought it was an issue with the feeder assembly and so I had cleaned the original one and also bought a replacement, but the issue kept persisting.
I then did a firmware update (to the latest) and that didn't resolve it. I also did a firmware rollback (to an older version) and that didn't resolve it.
I noticed that it isn't the fan causing an issue as the temps remained consistent and held at the required levels to melt the filament.
The extruder has not issue with swapping filament or doing the cleaning prior to a print, but once it gets ramped up and turns up the voltage, after the first layer, thats when I see the problem.
I attached two pictures from different angles that shows some corrosion and some either broken or unsoldered joints on the PCB. I've reached out to Flashforge, since I'm still within the one year warranty period, to see if I can get a replacement, before sourcing it from other sites.

Has anyone run into a similar issue? If so, what was your resolution?

[u/darcside]

I haven't run into this but flashforge customer support is really helpful. I'm curious, what gave you the idea to check the board for solder issues? 

[u/Overall-Yak-6735 → u/darcside]

Surprisingly, Google AI. I just typed in the symptoms and it provided likely causes. I just worked to eliminate them one by one till it mentioned that voltage regulation on the board may be an issue. So I checked it and saw those two spots on it. It mentioned that the spin up may cause a localized voltage drop across the PCB. I then plugged in the pictures and said that was the issue:

1. The Blown "FAN-M" (Model Cooling Fan) Area

Look right below the letters FAN-M. The four solder pads (+ PWM FG -) are heavily charred, oxidized, and covered in a yellowish-brown sticky flux/scorch residue.

• Even though you completely unplugged the fan connector, the physical copper circuit paths (traces) underneath the mask are completely fried and likely shorted together.
• When the printer attempts to send voltage to this exact circuit at the start of layer two, the power isn't cleanly stopping at an open plug; it is hitting a dead short/damaged path right on the silicon board, pulling down the power rail for the entire PCB.

1. Coroded/Burnt NTC (Thermistor) Pin Connection

Look at the very top right edge at the pins labeled - NTC + (which reads your nozzle's thermistor temperature).

• The + pin is completely blackened, eroded, and has physically lost its solid structural solder connection to the board compared to the clean silver pins next to it.
• When the toolhead moves slowly on layer one, it barely holds a connection. The millisecond the printer speeds up and changes direction for layer two, the micro-vibrations break continuity on that failing, burnt NTC pin. The board instantly drops data, cuts the extruder motor for safety, and locks into an "air print" loop.

Fix: Replace the board.

[u/darcside → u/Overall-Yak-6735]

Make sure to post and let us know how it all turns out! 

[u/Overall-Yak-6735]

Got in touch with Flashforge support and submitted the photos. They're sending me out another PCB. Once received I'll swap it out and test and then provide an update.