[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

[mark562]

Thanks George

I have wiring diagram #1943101 rev.H

I believe that this is a 24 volt system. I have a steady 26 volts at AUF plug JP4-2a (wire 186) and AUXBOB plug JP6-2a (wire 185) These 2 wires run to CR1. I also have 26v on both sides of both E-stop switches

On the Z-axis board
I have 12v at TB1-1 line 73 And 107v on TB1-3 & 4 lines 327 and 326 all the rest I have check for breaks all the way back to the boards they plug into.

All the drives have a GREEN led light on and the BMDC has 1 Green on solid and a RED glowing dimly the AUF board has 2 red led 1 solid 1 blinking.

Are there any other places I should check for 12v? I don't see any on the schematics.

The Z motor definitely has power to it prior to the computer booting and when I pull the encoder plug from the axsbob the motor reverses direction.


I have not yet checked the wiring outside of the cabinet as we were not having any problems prior to taking the computer boards out to clean.

[machintek]

We are getting places. You are getting more familiar with your machine.
The AUF does indeed run on 24VDC but also switches items such as a 110VAC coolant pump.
The BMDC has its own CPU and memory and more. During boot it loads software and those LEDs on it change state. It does not use 24VDC. The AXSBOB and AUXBOB boards are pin out boards for the BMDC. The AXS deals with encoder signals and uses 5VDC. there is a tantalum capacitor in one corner that the 5 V can be looked at. The AUX uses the 12 VDC. I do not know if such a capacitor exists on a AUXBOB where you could look for it. But you can look for it at the JOG, HOLD, START, SPINDLE ENABLE Should all work with the 12VDC.
Thus the question if the CR1 is a 12 V or 24 V device. Yes the enable signal as 24VDC goes through a set of contacts on CR1. Is CR1 pulling in? and when? Is it dropping out if ESTOP is pushed in? That is your next assignment.

George

[mark562]

Yes I am finally learning which boards do what. I am glad to see I am understanding this right. I will check in the morning to see if CR1 is actually working.

Now that I think back on it, the buttons you are saying are on 12v were the first to stop working when we were trying to fix the speed pot.

I always thought the speed pot sent it's own signal to the control. Am I wrong dose it also use the 12 vdc?
If the speed pot was not just loose again but has actually gone bad could it have shorted the 12v system and be the cause the ESPTOP alarm?

Mark

[machintek]

I believe the speed pot acts as a voltage devider and since it comes out of the AUXbob thus an extension of the BMDC, it runs on 12V.
The intent is to establish the presence of 12 VDC outside the BMDC. The next intent is to make sure that CR1 is not in a constant ON condition.
If you pull out CR1 or pull one of those 24Vdc wires going to the drive enable, the drift should stop.

George

[mark562]

George

I was able to get back to this today. I can see no movement in the CR1 relay when I push in the Estop switch but the drift does stop. I was able to find 5 volts at the resistor on the AXSBOB but I have not found a 12 volt source anywhere except for one component on the upper left corner of the BMDC board ( It's the only one I felt comfortable touching while the power is on) The last time I poked around soldered components I lost an AUF board in a fiery ball of sparks. All of the buttons that you say are 12 volts has either 0 volts or 2 to 3 volts.

[machintek]

I still believe you may have a issue with the 12VDC and/or the BMDC.
Two things you can do carefully.
Jumper the contacts so 24 VDC goes to the drive enable. This should shut them off and thus drift should stop.
See if 24 VDC is across the coil of CR1. Due to Ohms law (E=I x R) if the coil is energized, there will be a voltage drop across this coil. Or measure each side to ground. If energized one side will have a high potential with respect to ground and the other will be at ground. If both are high, the coil is not energized.

George

[mark562]

Today I tried your suggestion, I jumped the 24 vdc to the axis enable ( pin 1 on CR1) nothing happened but when I push in the ESTOP the drift stops and if I jumper the 2 pins again the drives will start and the drift returns,

As I sat there rereading your post to figure what try next there was a small shower of sparks and the smell of brunt electronics from my left, I think it came from the AUXBOB but could not find any burn marks. So I turned it off and called the repair man. I'm sure he will have bad news for me in the morning.

Mark

[mark562]

I now know why the Bridgeport company no longer exists, They hired morons that designed their BMDC boards backward then when the greedy CEO's didn't want to pay to redesign it they said "Just turn the plug backward and force it in and let the customer worry about fixing it"

Sorry about the rant I'm just angry that a bonehead fix to a major defect from 15 or more years ago has cost me a big chunk of change and none of those idiots are left for me to kick in the pants.

George I want to thank you for all your help your knowledge of these machines is invaluable to me and a lot of other guys on this forum.

I have sent my boards out to EMI to be repaired I will post here when I get the machine running again.