VFD interference problem

[eurikain]

I seem to remember that you can also power it through the USB socket. You could try this from the PC, if this works then longer term use a USB plug and lead but cut the cables, identify the power supply cable and wire it to an external 5V supply.

Yes, that's right, but there are two terminals made to replace the USB port, and I'm currently using them:

[JAZZCNC]

Yes, that's right, but there are two terminals made to replace the USB port, and I'm currently using them:

This could be your problem. The BOB is tying PC ground thru the PP cable to GNd on the 5V supply. For test remove the 5V and power bob using USB.

Regards Spare cheap BOB's that's like simple adding 2+2=4.???. . . Crap + Crap = Crap so why bother.!

[eurikain]

This could be your problem. The BOB is tying PC ground thru the PP cable to GNd on the 5V supply. For test remove the 5V and power bob using USB.

Okay this one also is a great idea ! That would explain why the noise does not appear when the PP cable is not connected ! I add this as first entry of my checklist.

Regards Spare cheap BOB's that's like simple adding 2+2=4.???. . . Crap + Crap = Crap so why bother.!

Always knew you were good at math :D

[eurikain]

Well, guys, problem solved ! Guess who was right ??????????
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JAZZZZZZZZZZ !!!!!

The 5V signal to the BOB had two routes to 0V... getting the 5V from the PC solves the problem :) This is why disconnecting the PP cable was causing the noise to go away, since it would suppress one of the two 0V possible routes.

Thanks for your help !

I do have one more tiny issue:
Mach3 controls the RUN/STOP signal and spindle speed fine, but the BOB seems to output an unstable signal for the spindle speed control. When running, the frequency can't stay still and keeps going up and down by 1-2 Hz, causing the spindle to run faster/slower (you can hear a slight increase/decrease in speed).

I can bypass this issue by disabling Mach3 speed control and only do the RUN/STOP, but while I'm at it, let's fix this issue if possible :)

[JAZZCNC]

Well, guys, problem solved ! Guess who was right ??????????

Always helps with solving problems if you give us all the facts.!!. . . . . It's was a rather important bit of info you didn't make available, esp considering the BOB and been accused prevously.!

I do have one more tiny issue:
Mach3 controls the RUN/STOP signal and spindle speed fine, but the BOB seems to output an unstable signal for the spindle speed control. When running, the frequency can't stay still and keeps going up and down by 1-2 Hz, causing the spindle to run faster/slower (you can hear a slight increase/decrease in speed)

It's called Crap Bob Syndrome and I doubt there's much you can do for it.!!

[Clive S]

It's called Crap Bob Syndrome and I doubt there's much you can do for it.!!

You could try giving it an Asprin

[JAZZCNC]

You could try giving it an Asprin

Nah Bullet straight between the eyes works every time.