Help or/and Advice Needed

I am having a problem in diagnosing a fault with Champion V20 Mill, was milling a component, finished the operation and set up for next operation when I switched on the motor it would run, but only if I kept the NVR switch manually depressed. The NVR switch was not latching in the run position, I thought the diagnosis was simply a faulty NVR switch, I obtained the correct replacement from Chester and fitted it but still the same fault. I checked inside the electrics box for any loose wires but everything was sound, looked for any obvious blown components on the motor control board but there was no sign of any problems, checked the wiring inside the motor shroud and everything was fine, as a last resort I took the earth point apart and thoroughly cleaned it and reassembled but the same fault persisted. The motor runs fine and the speed can be wound up and down as long as the green button is held in on the NVR switch. It seems to be a latching problem in the NVR.

I am beginning to suspect that maybe there is a fault on the motor control board, the one fitted to my machine is a BC 2000-TB DC Motor Controller, perhaps there should be feed back from the board which controls the latching of the NVR, I don’t know enough about the electronics concerned.

Has anyone else had the same problem with their machines, if so what fixed the problem. I am coming round to the fact that I may have to replace the motor controller board but preliminary searches on the internet show prices starting at about £80 upwards if delivered from China and at least a three week lead time. I would need to be certain that it would cure the problem otherwise I would be taking a lot of flack from the Financial Controller, the price , within reason isn’t a problem as far as I am concerned, I have had a lot of service out of the mill and this is the first problem in eleven years.

Heres hoping someone can put their finger on what my problem is. Dave W

If you're stuck, perhaps member John Rudd may be able to advise. I think he's done numerous posts on these sort of issues in the past.

Regards

Problem now solved, I referenced a previous posting from 2020 which had the same problem on a lathe and was brought about with a microswitch on the chuck guard not making correctly, I traced my problem also to the chuck guard, now that I am aware I will take precautions not to get caught out again. Dave W

Is it good design practice for the NVR to over-ride a guard safety switch?

Clive

Probably not. Dave W

Thanks for telling the end result.

That may save someone else from a lot of time and anguish!

Howard