VMC4020 Feed on all axis really slow

I was setting tool lengths today. The Z came down at it's normal brisk pace to the Tool setter. About half way thru my tools, it was crawling down, maybe 10 ipm. I notice all three axis are off. I ran the fadal test program and instead of 71 seconds I was getting 85, but either way I turn R6 adjustment it gets worst.

I also notice during the clock test, the axis will speed up for a second then slow down and is erratic. The test program over-rides the Feed Rate over-ride pot so that and it's wiring shouldn't cause that.

I suspect a bad clock board. Has anyone else seen this before I invest a bunch of money on a new card?

Richard

Maybe the feed potentiometer went kaput??? There's not much else in the way of that circuit.

ETA: Saw you "over ride" the pots. But for as cheap as they are I would swap them out first.

It ended up being a bad pot on the clock card. I replaced the card and installed my eproms from my old card and tuned it all again. It seems fixed.

Before I "fixed" it, It scrapped $3900 in parts one morning because it randomly drilled dowel pin holes in the wrong position. The hole pattern would be correct but shift one direction by .080" or some other weird value. I tested it several times after the repair and it seems okay, but I've been using a different machine to do the precision dowel holes because I'm just not trusting the old gal right now.

She has been thread milling and doing other bolt hole patterns fine and I'm getting more confident she's okay now.

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