Fanuc spindle will not turn on

[Scottjit]

I have a old machine with a Fanuc 0iTB retrofit. It has the DC spindle drive (not Fanuc) with +-10 vdc input. The machine was working good one day and the next day the spindle will not turn on. When I command a M3 S100 the drive pulles the contactor in but the spindle just rotates 1 rpm. I get all the signals out of the control for drive ready and contactor engaged but no +-10 vdc. I have checked the drive with a 1.5 vdc battery and it works correctly. I have checked in the ladder and I have all the correct outputs. I can not see the +-10 vdc except to measure with volt meter.

Could the power supply on the main board be bad?

[underthetire]

Or the LSI module on the MB.

[ben_heinman]

Could be in between gears and is trying to find the correct gear and that is why it is turning at 1 RPM. Try giving a S command and see if goes into a higher gear. and then try going back to the low gear if this works.

[underthetire]

Could be in between gears and is trying to find the correct gear and that is why it is turning at 1 RPM. Try giving a S command and see if goes into a higher gear. and then try going back to the low gear if this works.

good catch. I didn't notice the TB on the control. I agree 100%