R2E4 Drives won't sing

[Tom Long]

1985 R2E4 Series 2 has been working fine, and recently takes several hours before Drives sound right. Usually starts up with a drive fault on at least one axis. If it starts up and the drives aren't singing, the drives are shutdown on each request to Home the axes. When I bought the machine, I had a former Bridgeport tech convert the machine from 460 to 230 Volt. All that was done was change the jumpers on T2 and replace the heaters.
Just checked the voltages and my 24 Volts is running 33.6 (that can't be good) and the 90VAC is running 102.1. I am on a rotary phase converter with voltages as follows: L1-L2=254VAC, L1-L3=245VAC and L2-L3=245VAC.
T1 output is (wires 13, 12) is 122VAC, and T2 output is (wires 1, 2) 136 volts.
Does T1 also have jumpers? I also noticed a voltage conversion kit in the Bridgeport Parts manual (p/n 3-193-9648)- are there parts required to convert 460 to 230? T1 actually shows a different number for 460 volts.

[machintek]

Yes your voltage is high and these machines are not very fond of rotary phase converters. But you have to make do. If you have the original wiring diagrams there is a table for each transformer and how to wire it for different voltages.
As to the drive fault: The singing is actually the milli-henry chokes on the bottom of the cabinet. There was a very expensive option for chokes of a different value because schools complained a lot about the noise. BUT:
I find the drive fault interesting. The fact that time makes a difference leads me to suspect a bad capacitor in the drive power supply but the drive power is well up there. If you have the maintenance manual there is a trouble shooting section that gives the allowable range for each voltage.
There is a light on each drive indicating a fault or a drive off situation.
Does CR1 pull in? That is supposed to turn the drives on. You should hear a loud CLUNK as the three contactors (one for each motor) pull in when the drives are enabled.
What is the status of the FMDC? Are the two green LEDs on one end of the string of 8 LEDs at the top blinking? Yes at a different rate from each other.
Does the one LED in the middle of the EAF blink?
There is an outside chance that you have an intermittant connection which are a bugger to find. As some component or wire heats up, it makes again. Have you tries reseating all the boards and connectors? The logic card cage does hinge down. Is there anything loose or a chip floating around the back there?
What shape are the 4 AA batteries?

George

[Tom Long]

Found the wiring diagrams and T1 and T2 are wired correctly.
I do have all the manuals and checked voltages based on Chapter 7 (troubleshooting). My biggest concern is that all my voltages are above spec, and the 24 volt supply is really high! The manuals don't suggest any way to adjust the supply - will lower main voltage lower all the other voltages? I have variacs that can be placed on the phase converter supply if that is what controls everything.
CR1 does pull in but very weakly when the drives won't sing. Much louder when they do.
Another piece of data - yesterday, after several hours, the system finally came up, and would move all three axes. It would also do a rapid traverse (one axis) at the start of a program. Next step was a 2 axes rapid move and CR1 dropped out. Did this three times and tried a reboot. After that, it worked OK for a few hours, and then the singing went away and the CR1 dropped out again. That doesn't sound like corroded connections heating up to me, but I am no Electrical expert.
AA batteries are new.
EAF Led blinks green
LEDs on the FMDC are blinking green at different rates.
Got a new error when I started the machine just now - Internal communications error: Bad response from FMDC to BSP.
Acknowledged the error and the relays engaged. Tried to home axes and it shut down as usual. No singing.

[machintek]

Have you pulled out the FMDC and the BSP, cleaned the edge connector with a soft eraser, and seated them back in the card rack?
They talk to each other through the backplane.
The FMDC controls CR1. Reason being is that if it sees a problem, it can shut the drives off through the "zap string."
EAF not active, can't sink to host, and there is a third are normal boot up errors.
Have you gone to the Fist event monitor to see if there is anything logged there of interest?

George

[Tom Long]

Cleaned the contacts and reseated the boards. However, the FMDC slides into the backplane very easily and doesn't snap like the other boards. Is there some type of adjustment for that?
I added variacs ahead of the rotary phase converter and was able to get the input voltage down within normal limits. Also, the wild leg is slightly above 240. When I drop down lower, the FMDC and EAF leds go solid and don't blink.
Also, the 24 volt supply is still around 30 volts.
Now I can't get rid of the axis fault even though the leds are not lit.
I read somewhere about somebody rewiring the system to put all the transformers on the two standard legs and only using the wild leg for the motor. Do you think I should consider this option?
Tom

[Tom Long]

George,
Solved the loose fitting FMDC board. Just wasn't using enough force. The board snapped in and is quite tight.
Still got the axis fault - z axis now. Brought the line voltage to L1-L2=235, L1-L3=223, L2-L3=223. 90 VAC now 95.7, -22VDC now -19, 24VDC now 31.
Haven't checked the FIST monitor - next on the list.

[machintek]

Swap the Z board with the X board. The boards plug in just like the logic boards. There are 4 wires on the bottom of the axis drive going to the motor. They have to swapped too.
If the problem follows the board to the new location, it means the board is bad. If it stays with the location, it means there may be a problem with the motor or cable.

George

[Tom Long]

I did swap the Y and Z and the related wires, and the fault light moved with the board, at first. Then it cleared and looked like it would work, but the singing never came back. Any attempt to home the axes throws CR1 out, but the axis fault error doesn't come back. The funny part about the axis fault on startup is that there usually is not a led lit - it just says there is an axis fault. My biggest concern right now is that now the singing does not come back, even after 6 hours in standby. Is there any way to test the capacitors?
By the way, thank you so much for all the help you have provided so far!!!!

[machintek]

There must be a reason that CR1 does not pull in. What does the fist event say?
If I remember correctly, the red LEDs on the drives should be ON untill the drives are turned on. Strange.

George

[Tom Long]

I may not be explaining things correctly. When I press the axis enable switch, there is a loud clunk and all three relays engage, but the drives don't sing - sometimes one solenoid buzzes. Pressing Execute always results in a loud clunk (the three solenoid disengage).
Regarding the leds, if we are talking about the one in the middle of the front panel for each drive module - they do not come on unless there is a drive fault.
Fist event log has lots of entries - all the same ones. 13FC Not error Host Comm E Stop and OED6 E stop. I assume that I should be reviewing the end of the log not the beginning (00 time entry). Is that correct?

[machintek]

The singing comes from the chokes. I have to find a schematic to refresh my memory as to where they are in the circuit. The fact that the motor contactors pull in but there is no singing means there is no current. This means that the circuit is still open or that the drives are not doing anything. The fact that the LEDs are NOT lit prior to drives enable indicates to me again that there may be a power problem to the drives. Check the IFC_DPS assembly DPS stans for drive power supply. There is a green connector there with 5VDC written on it and possibly 12VDC. Check with a meter to see what voltage you do have. This assemly is left of the 3 axis drives.
When you command the home move the drives drop out because you have a fault. The control commanded movement and none occured.
The first item to come up in the fist monitor is the most recent. Scrolling down gets you to older events. Sometimes, you look beneath a ZAP or E-stop to see what caused it. The time on the left is the time from when the event log was accessed. There are also severity indicators.

George

[Tom Long]

The system appears to be getting worse. It now does not recognize number entries to access the FIST event log. Drive errors still keeping CR1 out but all voltages appear to be OK. Anybody have a clue as to what I'm missing?
Tom