[johnhb]

After we replaced the mother board on this machine it has developed a problem where all three axes are unstable in jog. Over the past several months it has gotten progressively worse until I can set a location only in "slow".

Once set up and running - no noise, no problem.

I assume there is a way to adjust the stability and since this started with the replacement of the mother board and hard drive I believe the problem is somehow related.

Can anyone tell me how to fix this?

Thanks for your help.

John

[machintek]

Where did you get the motherboard from? What software and DOS version are you using? Are they the original versions?

George

[johnhb]

George,
Motherboard, hard drive, and software are all from EMI, replaced last August with no problems until now. Voltage measurements on pwr. supply are OK but since it is from 1998 I will replace it.

Machine developed a new problem - the display on the screen and keyboard will cease to operate. The BMDC, and the machine controls still operate normally - you can continue to run the program until the end, and restart to run it again. Only the numeric X,Y,Z positions are functioning on the screen.

When the system is reset the "must load executive hit F9" message shows up, but when this is done result is a corrupted display of the "F9" message with missing letters, etc. finally system goes to C:\ and if "Run" is entered the whole process repeats. I find it interesting that that the motherboard is still working since C:\ is displayed, BMDC is still working, but MB and BMDC are not communicating. How is this supposed to work?

Next day system started normally, everything OK, I was able to get halfway through the part when the above sequence repeated.

On the jog noise problem; per EMI suggestion, when the jog encoder
is disconnected the noise goes away. I will replace the encoder as soon as my more serious problem is resolved.

Appreciate your help, John

[johnhb]

New problems;
Jumpy in jog went away, but now machine will be suddenly stop with spindle turning and XYZ not moving because cnc program has vanished along with tool offsets and program zeros.

After reload will run for an hour or so, do it again.

New symptom, today while running machine shifted zero 6 inches or so, but continued to run otherwise normally. Program and tool offsets still there.

After re-homing all back to normal, briefly at least.

What can cause these symptoms?

Thanks for help,
John

[machintek]

The program gets transferred to the BMDC and run from there. Encoders go there also. Sounds to me as if you have a BMDC issue or a power issue to it. Possibly a bad connection.

George

[johnhb]

George, Exactly right, connector at top of BMDC was missing screws and backed out. This is probably result of my efforts to diagnose the other problems.

Today I am installing refurb BMDC from EMI, hope it cures the list of problems.

When did Bridgeport add the circuit breaker to 5 VDC for encoders? I cannot find it on my Explorer schematic. I think our machine is relatively late but if the circuit breaker is not there I will add the fuse per your earlier suggestion.

Thanks again for your support.

John