VF-4 Control computer repeating characters

[Drkk]

Haas VF-4, New in 99, aircraft and electronic parts.

During operation a line of characters (in this case, the letter e) begins to appear at the bottom of the CRT display. There is no common factor as to when they begin to appear (checked temp, voltage, on time, load factors, etc) and they go away once the machine has been shut off for ten minutes or so.

Called Haas, and it seems to be a common problem that is easily solved by sending in the computer and a pile of cash and getting a replacement unit. Being cheap, I'd like to avoid sending them $1,500.00+ if the fix is something as simple as a cold solder joint on the mother board.

Anybody have a clue what might be causing this "common problem?"

[gar]

050920-2011 EST USA

Drkk:

No idea.

See if there is an easy way to disconnect or disable the keyboard while this is happening.

If the keyboard is disconnected and it stops, then most likely the problem is associated with the keyboard.

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[ZR Machine]

Mine does the same thing with the letter T from time to time, It is the keyboard and the E is sticking.

[Drkk]

Nope, not the keyboard or any of the components in the pendant, because I swapped out the entire suite with my VF3, and the problem stayed with the VF4.

[gar]

051101-2051 EST USA

Drkk:

Open the main control enclosure. Set up a fan to blow air around the upper left corner where the main processor board is hidden behind a plate about 1 ft square. If this corrects the problem, them something in that area is thermally sensitive.

Be careful because high dc and ac voltage is exposed here.

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[Drkk]

Already tried, with a air powered cooling unit. No joy. I have yet to remove covers in the CPU enclosure however.