Denford Software & Machines

Customer writes:

I am having issues with our CNC Mill.
It was purchase by our school around 1999 T

The PC would not detect the machine so I opened the back to find a blown fuse. So I replaced with an identical fuse and powered on the machine and I started smelling a burnt smell. I shut it down unplugged and checked everything, and I could not find anything wrong, but it had blown another fuse. I swapped out with another fuse, the machine came on the controller card came on, and then LED threw a L and then a 8. Then it went off, due to that fact it blew another fuse.
What do I need to do?
I have included 3 images of the controller board, the fuse plugin and the model/serial info.
Thanks

The fuse that has blown is the one that supplies the power to the control card and stepper motors.
In the first photo you attached (where the fuse is shown missing) the orange connector below the fuse holder carries the supply to the board.

Could you disconnect all the other orange connectors from the board other than this one, replace the fuse and switch it back on. If the fuse blows now then there is a fault with the control card. In the same photo at the far right of the picture you can see the legs of the 3 15 pin stepper motor drive chips. It could be one of these that has failed. If you inspect these you may see damage to one of them.

If the fuse does not blow then it could be an external fault that is causing the fuse to blow. Refit all the orange connectors apart from the two at the top right of the board and the one in the bottom right corner (these are the axis motor connections) and power on again. See if the fuse now blows.

If the fuse has not blown try refitting the stepper motor connectors one at a time to determine which is causing the fault. I would also check the motor leads for damage.

We have a technical forum, I will add your questions and answers here so others can help you out as well.

Here is a link to a post identifying the connectors. The incoming power is the connector to the left of the Z Motor.

viewtopic.php?f=54&t=1627


Please let me know how you get on.