Need Help!- Fanuc 3T "Not Ready" Help!

[pmcg]

Alright: I need some expert advice. I have a 1984 Citizen L16 with a 3T (A?) control with 30M series servo control that is kicking my butt.
I am not an expert but I have the ability to read schematics and to a small degree ladder logic. I have the machine manual with wiring and ladders and the 3T Maintenance manual. I've solved a few problems in the past on my own but this one has me thinking I was just lucky rather than skilled. I am at a stand still on this one;
Symptom 1: X axis started to oscillate and then would ran away to fault (hard overtravel) Had the guys pull the brushes and clean the commutator with no change. manually wound the axis off of the stop. Checked mechanical conditions and everything was OK. While trying to solve that problem the machine went to;

Symptom 2: "Not Ready" with no errors. No MCC.

Diagnostics:
701.5 = 1 = CRST = E Stop, remote reset or MDI Reset turned on.
So E stop right?
Jumpered around the push button.
(This machine is set so that the MDI Estop push button kills everything and only a single push of the Start button should bring the whole thing up including the MCC).
E Stop MDI diag bit responds to button
Ladder says everything is good (all diag bits are correct to drive ESP and EMG coils) but
ESP (from the Machine Tool to the NC) diagnostic bit (101.4) shows 1 (have a note in the original machine manual that says thats correct)
But the EMG (from the "PC" to the Machine tool) (48.6) shows 0 (bad (?))
I can manually drive down the the EMG Machine Tool I/O coil but no change.
PRDY is the Machine Tool I/O coil that turns on the 100V to the Servo unit.
I can manually drive the PRDY relay down and the MCC connects and the hydraulic unit starts but no change in the diagnostics and won't stay latched.
I have wiped and reloaded the parameters and program memory.
I have been through all of the limit switches and no problem there.
I have checked and re-checked power supply(s) output and it is within specs.
I have checked every fuse I can find on the machine
I have pulled the PC boards and all of the PCB connectors looking for bad connections.
I have checked voltages of PCB and Servo board and all appears OK (Fanuc Maint. manual not much help here because it covers all of the Servos that came with the 3T).
The Servo unit has breakers and no fuses.
No errors and no sign of fold-back on PS.
Diagnostic bits for axis OT respond to limit switches.
The OV and OH alarms show when the motors and encoders are disconnected.
I have read the ten pages of hits for "Not Ready" on this board as well as any other source I could find.

Some other diagnostic bit info:

113.7 = 1 = MA = Machine Ready (? )
23.7 = 1 = VRDY = Servo Velocity Control Not Ready (But no Red LED of the Servo Board and no Alarm 2 and the Green LED "VRDY" on the board is lit. I'm assuming since the MCC never made the signal is not making it back to the NC)
129.7 = 0 = ALM Alarm
100.1 = 1 = Interrupt

I am starting to wonder if the ROM is the problem. Not a major problem that generates an error but a scrambled piece of code that makes the machine think everything is OK.
But I can navigate through the screens and low level diagnostics respond to Machine Tool.
The control even energizes the Bar Feed relay coil a second or so after start is pushed and that is way down the ladder (The I/O board appears to be OK as it responds when fuses are pulled).

In the interest of logic I would focus on the Servo unit since symptom 1 would point to it but since I have found nothing wrong with it yet I'm wondering if it was just a result of another problem.

I am starting to wonder if I missed something simple. Shouldn't the PC energize the EMG coil if all of the ladder conditions are met?
I don't mind going back to the beginning and checking everything over again but any advise that points me in the right direction would be greatly appreciated.
And don't be afraid to take me back to the basics because at this point I'm assuming I need it.
Thanks in advance.

[Al_The_Man]

Originally Posted by pmcg Symptom 1: X axis started to oscillate and then would ran away to fault (hard overtravel) ESP (from the Machine Tool to the NC) diagnostic bit (101.4) shows 1 (have a note in the original machine manual that says thats correct) .

Sounds as though you have a separate fault there to the original?

101.4 Estop is marked with an asterisk, which means it is active low, so a 1 should be OK.
The 100.1 STLK Interlock may be the problem.
Did you look at the Diag 700, 701 712 and 800 801 820 821?for the respective state of the status bits.
Its been a while since I worked on a 3T of any kind!
Al.

[pmcg]

Al; thanks for the reply. 700 thru 822 are all 0 except for the 701.5. It's like it never got past that point. The STLK (100.1) rung shows 2 paths and 5 contacts. They are for turret indexing> making sure they are in position to index and ready. I'll go through that rung and see if anything shows up. Thanks

[pmcg]

STLK (100.1) - All NO contact diagnostic bits show 0 and the 2 NC show 1. But 101.1 = 1
So no luck there.
Looking at an old 6T Fanuc Maint. manual with a flow diagram it shows after ROM check (I know its not the same but it is the only flow diagram I could find).

"1. Interrupt Release 2. E Stop Monitoring 3. Position Control LS1 set 4. MCC in velocity control On"
So does 101.1 = 1 mean it never got past "interrupt Release"?
Thanks

[Al_The_Man]

That would be my guess, maybe Dan Fritz may shed some light on it?
Al.

[tc429]

dont have a 3t address list handy, but bet when it ran away the overtravel got damaged(or the rarely used stop button contacts failed)...the highspeed inputs for estop overtravel and a few others require the input to be high- jumping the output wont do it...

also check terminals 3 and 4 on the drive (assuming 6047 amps/yellow caps) should have 100 volts... some estops have parallel paths for shutdown- one 24v input, one 100v power to the contactors...

the little brown blocks on the now 20+ year old fuji estop buttons Ive had a lot of issues with the past couple years, hitting estop(two circuits on the button) and resetting sometimes one contact wont reclose... nice thing is, just remove the screws fully, slide out the contacts and clean the silver pads, good for another 20 years...

[pmcg]

Thanks for the reply: I'll check for the dual circuit Estop. I pulled the X axis micro switches off the machine and checked them and they are OK. The 100V between 3 & 4 are what energize the MCC starter coil and the leg going to 3 is open until the PRDY is made (although the wiring diagram shows the EMG contacts in that circuit). I can force the MCC on through the PRDY I/O relay but I did not try both the EMG and PRDY relays at the same time. I'll see if I can draw out the 100V circuit based on how it is actually wired vs the diagram and see if it gets any clearer. This thing has seen some repairs before we got it and it might be the case that the diagram and actual wiring no longer agree. Thanks again.

[pmcg]

E Stop is dual contact but both the 100V and the 24V were working. 100V makes it to terminals 3 and 4 on the velocity control unit when the EMG and PRDY I/O relays are make but that is not what energizes the MCC. It needs the contacts in the control made for ENBL (Enable) and PRDY. Went back and looked over the drive again. I thought the MCC contactor was making but it wasn't. It was another contactor in the cabinet. Checked and found that the ENBL and PRDY on the drive were sending 24V out but not getting it back from the control. I pulled both of the PC boards and looked them over closely but nothing looks amiss. I checked the voltages on the boards and they were OK. I went back over the ladder and found that there is a -X jog coil made early in the ladder (S5B) that should not be on. Pulled the hard wire off the joy stick but made no difference. the only way I could get it off was to pull connector M1 off the PCB but got an axis alarm so I couldn't tell if that would help. I pulled the Honda connector apart to see if there was a short but looks good. I'll spend tomorrow back probing the M1 and connector and the M18 connector (this is were the -X signal should be coming from). Still wondering about the ROM.