FINALLY!! Cricut Easypress 2 E3 REPAIR!

How to diagnose and repair your cricut easypress when it displays the E3 error.

** UPDATE ** - sadly this unit succumbed to the same fault not long after. I don't believe the triac is to blame I think either the firmware has a bug or there's a hardware issue which causes it to not sense the temperature randomly and so keep the power on indefinitely and blow the thermal fuse or maybe the processor is locking up while in a heat on state (this would show as the buttons being unresponsive or no other feedback from unit once the fuse has blown). I was unable to get it back to try do a full analysis to figure it out. Your results may vary.



Tools I use -

Soldering
Quick 861DW hot air station
Duratech TS-1640 solder iron

Multimeter
RMM760D - can be found under many name badges

Microscope
Luzky Zoom 3.5 - 90x simul-focus single boom stand trinocular stereo microscope
Camera - Lucky Zoom HD 14MP

Oscilloscopes
Siglent SDS 1102CML 100MHz 2CH
Philips PM 3305 35MHz 2CH

Bench supply
Powertech MP-3086 0-30V 3A

TL866II PLUS universal EEPROM programmer