Denford Software & Machines

Microrouter Compact

Serial Number: UOO442/15

Control Software/Version Number: VR CNC Milling/ 2.31.3.951

Dispatch Date: April 2004

The control transformer output fuse (F3) blows just after starting the machine. Before blowing however, the LED display shows an 8 so everything is starting up ok until the fuse blows. The replacement fuse is a 10A 250V fast blow. Could be the wrong fuses. If not than we don't know what's wrong.

The F3 is a 6.3amp fuse (Radio Shack P/N 270-1068)

First look at the 3 large transistors mounted on the heat sink of the control card. Look for any cracks or holes in the face of the transistors(holes or cracks = card shot), if they appear OK then continue on. Check the fuse (6.3amp) on the control card also.

I would first unplug the three stepper motor from the control card(TB 5, TB 6, TB 12) and unplug the "Z" Brake from its circuit. Then plug one in at a time to see which one burns out the fuse, it maybe one circuit or a combination, then trace the wiring looking for a grounded out lead.

Customer called and states that F3 (6.3 amp. control card 24v supply) keeps burning out.
Recommend giving the machine a thorough cleaning. Use a vacuum cleaner first to get out as much dust as possible, then use compressed air to blow out the remaining dust. Use Spray Silicone Lube on the slides and lead screws to lubricate - DO NOT USE OIL!