Please Help Again

[mark562]

We were having trouble with the speed pot coming lose and reading the wrong RPM on our BP Explorer/DX32 when trying to adjust it we broke a wire off. At this point several switches stopped working.
jog/rpm+/-
spindle stop
cycl start
spindle enable
all stopped working so we turned off the machine and re-soldered the wire we broke and restarted machine but there was no change

Thinking we blew a fuse I opened the cabinet door and found the new AA size batteries exploded (some one had put in standard alkaline instead of the rechargeable I had bought).

I disassembled and cleaned every board and reassembled aside from some missing finish on the CPU heat-sink I think I caught this in time to avoid major damage. However now when we start the machine the computer boots OK and BMDC loads and operator interface starts with the error EMERGENCY STOP ACTIVATED and I can not find the fault.

Any ideas would be greatly appreciated

[machintek]

I do not have a schematic in front of me but I believe these switches work on 12VDC.
This comes from the logic power supply,through the mother board, through the BMDC.
If that wire was a 12V supply wire and it shorted, it may have blown L2 on the BMDC.
There are not a whole lot of these machines out there. Thus my memory is a bit fuzzy what is inside. So see if I am correct.

George

[mark562]

Thanks for the quick reply George

The L1 component seems to be fine there are no visible signs of damage and I get continuity from side to side. After I get this put back together again is there some points on these boards that I can test for the 12 volts?

Mark

[John Bennett]

I believe the V2XT and Explorer with BMDC DX-32 control are very much alike. If that is correct then the attachment might help for flow of circuit.

[mark562]

Thank you John

You are correct the V2XT & EXPLORER are wired the same, I was able to find that the Z-axis is sitting on it's minus limit switch.

I manually move the quill up an inch or so and turned the power back on and noticed the Z motor is under power and feeding at a slow feed to the bottom of it's travel. It is still in E-stop condition when this is occurring and there isn't sufficient time to check more voltages before it gets to the limit switch and shuts every thing down again.

Does this shed any light on the subject for any body? Where do I go from here?

Mark

[John Bennett]

To quote an expert (George)

Any time a axis drifts, the position loop is compromised (open). Thus I believe you may have a cable issue.

Do you have the schematics for the drives?

[mark562]

I suppose it would not have been hard to break a wire with my knee, I will check that out Monday. I have the wiring schematics for the cabinet but not for the drive board it self. I did notice that the drives are not marked do you know which one is the Z-axis board?

[machintek]

L1 protects the 5VDC. L2 protects the 12VDC.
Usually the drives are from left to right X, Y, and Z. Checking wire numbers on the schematic will confirm that.

George

[mark562]

Thanks George
Am I correct in assuming that L1 & L2 are good if there is no visible damage and have continuity on both.

[machintek]

Correct on L1 and L2.
Usually, when I lose 12 VDC, I first look at the mother board. The older mother boards had a NiCad CMOS back up battery soldered onto it. Eventually it will leak and the electrolyte (sodium Hydroxide or was it potassium hydroxide) will eat away the wires deposited on the board. Usually this battery is near the keyboard plug and usually so is the routing of the 12V.
If you search the archives, this has happened numerous times. Of course if you have a newer MB with a coin style lithium battery, this is not a issue.

George

[mark562]

I was able to get back to this machine today.

George
I could not find a component that was labeled L on the BMDC but I did not find any damaged components. I had replaced the battery you spoke of weeks ago with AA batteries, it was these replacement batteries that exploded. I have cleaned and inspected every board and traced every wire that I could follow om the schematics and can find no damage and no broken wires.

Still when I switch on the main power the Z axis starts moving down until it reaches the z- limit switch. The computer continues booting normally until it reaches the operator interface screen, Then shows alarm "EMERGENCY STOP ACTIVATED"

When I push in one of the E-stop switches the power is cut to the drives and the Z axis stops moving so I know both are working.

Is there anything else I can try before I call a repairman out?

[machintek]

I see conflicting statements that are very important.
If the axis drifts down in ESTOP, then the axis is powered up but the control is not monitoring the position loop.
If it drifts when powered up, then the position loop is compromised.
When I set up the drives, there is a drift pot or balance pot. I pull the encoder cable for that axis and adjust the drift until the axis is stationary. Thus if tuned right you may not see a drift of any axis while it is stationary. The Z is brought down by gravity but drift can be down by jogging up and down and watching the lag.
Drives are enabled by 24 VDC coming from the AUF through a set of contacts on CR1.
CR1 is enabled between the AUXBOB and the AUF. See the wiring diagrams.
Pull CR1 and see if it is a 12 or 24VDC device. All those things coming out of the left side of the AUX are dependent on 12 VDC.

George