Taz 3 pcb micro fuse blowing

I was running my Taz 3 in production mode. At the end of a multi part print, I went to set up the next run and the LCD was dead.

Checked the 24 power supply output and it was good. No blinking lights on the Taz3 PCB though.

Checked the 15 amp automotive style fuse on the PCB and it was good. Then checked the PCB micro fuses. The upper one had continuity. The lower was open circuit. Changed the fuse and everything came to life… for 30 seconds.

As I autohomed the printer head, everything went black again. Changed the lower fuse again and got a repeat. So something is causing high current through that circuit.

My next steps are to disconnect the bed heater, the print head heater, and all drive motors to isolate any fatigued wire or failing drive motor or component. I’ll then reconnect one by one and see if/where the issue is.

Any other suggestions?