You can test the Lombard internal fan by itself. Disconnect it and make a drawing of the three wire colors and where they go into the plug housing. Then if necessary remove the connector pins temporarily from the plastic block with a jeweler's screwdriver and power up the red and black to +5VDC and ground respectively. The fan should run at full speed. Mine starts up with as little as 2.3VDC. The yellow is a square wave TTL tachometer output. View it on a scope or counter and slow down the fan with your finger to verify the frequency tracking with RPM, constant amplitude, and that it stops completely when you stall the fan.

If the fan checks out ok you can also check the Si9933 motor driver FET pair nearby and maybe the LMC6462B opamp U20.