1992 VMC20 Crazy screen and control keeps resetting

[Fadal Error]

So my early 90s VMC20 with the 88 control is acting up. Sometimes it takes 3 or 4 tries to even get the control to start up. Sometimes I get the crazy screen pictured.

Now the control will just reset randomly. It will be sitting idle or running the program and suddenly it stops and reboots. Tells me to jog to home position and enter CS. Strangely, when I go to jog mode it shows its actual position so I can just move it to zero in all three axes and cold start it.

It has been getting the unrecoverable memory error if it sits for a week or so without starting it up. I just re-enter the parameters and it is good to go.

Any ideas what the issue is?

Attachment 403744

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[ianagos]

Have you tryed powering it down and removing the cards in the card cage one by one and reseating them? Also reseat the cards on the cpu board.

Along with that get a decent multimeter and check the 5v and 12v from the power supply should be with .1 of nominal.

[ASIGuy]

To begin with, you need to change the battery on the processor board. Once this is done, run the zero memory procedure. I have a copy if you need it. We have the batteries in stock (ELE-0082)

As posted earlier, check your low voltage power supply and in particular, look at the 5VDC output. It must be +-.1VDC. The 12VDC is not nearly as regulated but usually within a half of a volt. I would reseat the software module on your processor and make sure it is tight with good connections......and clean. Dirty boards will have all kinds of odd problems.

If your power supply looks good (under load), I would begin to look for a short circuit in the wiring somewhere. I had a machine once that was doing the same thing and it turned out to be a short in the head. The cable for the orientation sensor was dragging on the spindle pulley and wore the insulation off and was shorting out intermittently. Meg your motors and make sure you are not seeing carbon arcing in the motors. If you meg the motor cables from the amplifier to the motor and showing bad (5 meg or less), then remove the cables from the motor and meg again. If you have a good reading, the cables are good. Bad reading means the cables are bad, but you still need to meg the motor and see if it reads good.

If all these tests come back negative, then write back and let me know what the results are and we can start troubleshooting from there.

FadalCNC Tech Support

[Fadal Error]

Thank you for the responses. I will try them out when I get a chance.

One issue I have had for a while is that the machine overheats on hotter days. I keep the cabinet open to let it cool off. The boards get dirty as a result. This may be a result of dust, etc getting in there.