Fanuc 15-t spindle RPM maxes out at 45 RPM No alarms

[TM1]

I have a mori lathe with a Fanuc 15-t controller. When I input a RPM in MDI say 1500 RPM, spindle only turn 45 RPM. I'm not getting any alarms on the machine or on the spindle drive. It has a Fanuc spindle drive A06B-6055-H422.
Same also happens when I use the manual button for turning spindle like in jog mode. It will max out at 40 some rpm. When I use revers and turn the spindle Pot it slows down and reverses, but only in revers.
I swapped out the control drive front board thinking it was the issue. Same issue.

 

[Human]

Bummer. Have you carried out a visual inspection of the drive board/components? See if anything is overheating or worst, magic black smoke around one or more components. I see quite a bit of power mosfets and high voltage/current transistors on that board... those rarely live eternally. Particularly the 3 mosfets on that heatsink (bottom left), I'd start there - see if one is shot (they normally have their pins shorted when they fail, check with dmm).

https://inprosols.com/wp-content/up...-A20B-1001-0120-Board-Tested-164424034557.jpg

 

[TM1]

Bummer. Have you carried out a visual inspection of the drive board/components? See if anything is overheating or worst, magic black smoke around one or more components. I see quite a bit of power mosfets and high voltage/current transistors on that board... those rarely live eternally. Particularly the 3 mosfets on that heatsink (bottom left), I'd start there - see if one is shot (they normally have their pins shorted when they fail, check with dmm).

https://inprosols.com/wp-content/up...-A20B-1001-0120-Board-Tested-164424034557.jpg

I swapped the whole board out for another one that supposedly came from a running CNC (eBay). I can check the MOSFETs tomorrow but it seems unlikely both boards would have the same failure.

 

[CITIZEN F16]

What does the RPM say on the spindle drive?

 

[Human]

I swapped the whole board out for another one that supposedly came from a running CNC (eBay). I can check the MOSFETs tomorrow but it seems unlikely both boards would have the same failure.

I get it now. Did read control drive front board in the OP, had me confused. Wow no alarm, don't you love some good old EE with poor self-tests.

Ruled out the pot's contacts/resistance?

 

[TM1]

What does the RPM say on the spindle drive?

I didn't think that style showed the rpm, so I never checked. I'll look at that next. On the controller it shows 43 rpm.

 

[TM1]

I get it now. Did read control drive front board in the OP, had me confused. Wow no alarm, don't you love some good old EE with poor self-tests.

Ruled out the pot's contacts/resistance?

This model has a stepped switch instead of a actual pot. I looked up the inputs in the ladder and could see all bits changing as I rotated the switch. Plus it does it on m codes also.

 

[CITIZEN F16]

I didn't think that style showed the rpm, so I never checked. I'll look at that next. On the controller it shows 43 rpm.

What is the model of the Spindle Drive? Some of them you can change what is displayed by keypad in puts.

 

[Vancbiker]

Was there any memory loss or parameter messing with done? Is this a new to you machine or have you had it running a while?

Spindle speed control is often a combination of CNC and PMC parameters.

 

[TM1]

What is the model of the Spindle Drive? Some of them you can change what is displayed by keypad in puts.

It is a Fanuc spindle drive A06B-6055-H422.

 

[CITIZEN F16]

It is a Fanuc spindle drive A06B-6055-H422.
View attachment 341979View attachment 341978

All the Fanuc controlled machines I have owned came with either Frenic or Yaskawa spindle drives. I am not familiar with the Fanuc ones.

 

[TM1]

Was there any memory loss or parameter messing with done? Is this a new to you machine or have you had it running a while?

Spindle speed control is often a combination of CNC and PMC parameters.

I checked all the parameters on the drive, and entered them into the new board. They were the same as notes I had. Machine was running good, had gotten mice in it, but I repaired all the wiring. Most of damage was in the crt console. I've gotten everything else working and the spindle issue popped up. I can't find any more wiring issues. I'm thinking possiblity an issue with the pcm but unsure how to test it. If I remember correctly the f's and g's in the ladder show the communication of the PMC, but I can't find my manuals that show that.

 

[GENERALDISARRAY]

It is in G97 right?

 

[TM1]

It is in G97 right?

Yes, checked G97.

 

[MwTech Inc]

You say mice?? Little buggers will mess up a lot.

Just went thru that on my VMC i picked up this fall.

I thought I had repaired all wires but it only takes 1 to have something not work.
And yes I did miss one wire in a 50 wire bundle

But after i found it all started working.

You could have a wire that was chewed and now that you were in the harness it is open................