Problem- VMC 4020 monitor blowing fuse

[cncman-818]

We have a VMC4020 and the monitor is blowing the fuse for the 120v input

I removed a monitor from a working machine and it blew the fuse about 2 hours later s@#&

I repaired the old monitor and installed it in the machine I removed the replacement from and it works.

I repaired the fuse on the monitor in the troublesome machine and attached it an external 120v source the fuse does not blow

I monitored the power supply with an oscilloscope but nothing was observed

any clues?

Regards
Matt

[iess525]

What year is the machine?

[cncman-818]

Originally Posted by iess525 What year is the machine?

1998

[iess525]

It sounds like there is a short somewhere.

[TRACYPFAB]

Has the monitor been working in the past? Sounds like you might have some high voltage, 220-440 shorted onto the monitor power.

[alex gitzel]

Is it blowing the fuse in the back cabinet by the control cards that feeds the pendant or just the one on the monitor?I would track the wires back to the dist. board behind the switches and check the power for shorts and voltage,also look for any burned up components on that board i have replaced several of these dist. boards in the past with the same type of issues.the wires go to the board at j12 pins 1+2.

[cncman-818]

As I said...

The fuse on the monitor itself is blowing.

I removed a monitor from a working machine and installed it in the nonworking machine and the fuse in the monitor from the working machine blew after about 2 hours.

To get production going I connected the monitor to an external 120v power source until I can have the machine. It has been running for 2 days as of now.

I had a recording device connected to the power source for the monitor connected to the wires (molex connector) in the machine and noted no anomalies

I did ask the operator what sequence of events lead to the monitor going dark. In both cases the machine was just running in auto and the operator was involved in other tasks. No switches etc where pushed turned etc on the control panel.

[alex gitzel]

The system is fairly basic the 120vac comes out of the transformer,to the 1100-1 power dist. board(by the amps),then out through the pendant fuse through the top track and into the power dist.board in the pendant if there are no shorts in that part of the system i would swap the pendant power dist. board with another machine.9 times out of 10 when i am called in on an issue like this that board is the issue.issues can be intermittent sometimes and everything looks good but when put under load it will act up.i do see the beacon light is also on the j12 plug there may be an issue there.i have also seen components on other plugs on the board cause issues on another.it all depends were the issue is and what sequence of events cause the problem.you can get the wiring manual from fadalcnc.com and download it.

[cncman-818]

Originally Posted by alex gitzel The system is fairly basic the 120vac...

Yeah basic as it gets

Originally Posted by alex gitzel i would swap the pendant power dist. board with another machine.9 times out of 10 when i am called in on an issue like this that board is the issue.

This was the recommendation of our new hire of 2 days

Originally Posted by alex gitzel issues can be intermittent sometimes and everything looks good but when put under load it will act up.i do see the beacon light is also on the j12 plug there may be an issue there.i have also seen components on other plugs on the board cause issues on another.it all depends were the issue is and what sequence of events cause the problem.you can get the wiring manual from fadalcnc.com and download it.

Thanks for your sage advice... We'll redouble our efforts !

This is my first experience with any real trouble with a Fadal...

It seems the wiring is a weak point with these machines

Cheers
Matt