Hooray! Fixed!

I live on an island and it is hard to get CNC repair people out to look at the machines. So I fix 'em myself. The Miyano lathe developed a problem last week. It refused to execute one particular M code, the spindle speed could no longer be controlled in a program, the jog spindle speed dial now controlled speed even in auto mode when it should not, and the "used up" alarm came on after every part. I called FANUC and they figured it was a particular circuit board. I found one on eBay and ordered it. But it's a week and a half away. I checked all the diagnostic parameters and everthing was fine. Then this afternoon I checked the regular parameters and one had changed. A parameter who's function is not listed in the book so I didn't know what it did. But I had written down all the parameters when I bought the machine, they are mostly 8 digits long, just ones and zeros, but some are otherwise, such as backlash amounts, which are entered as some multiple of one ten thousandth of an inch. The machine was used when I bought it so some of the original parameters could have changed, like backlash. And I have changed parameters too in order to get the machine to do things it did not do when I bought it. So I got into the back of the machine, where all the high voltage is, along with the computer, opened up the computer enclosure and flipped the parameter change switch. Then I used the control keyboard to change the parameter back to where it was, got back behind the lathe and flipped the parameter switch, cleared the alarm that happens whenever a parameter is changed, and the machine now works great. All I did was change a 0 back to a 1. I wonder how the damn parameter changed in the first place? Anyway, I am really happy now. Really happy. I mean REALLY HAPPY! Eric

Reply to
etpm
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Yeah, sorta like rule 1 "Reboot" :-)

Reply to
Rheilly Phoull

Very wise!

Might have been a bit flip in memory somewhere (cosmic ray, bad IC, etc.).

Or, is possible to change those parameters under software control that doesn't require the manual "parameter unlock" switch? A garbled command sent to the device - even a one-character error in transmission - might have "silently" changed a parameter in an unexpected way.

Or, maybe, this parameter was changed as a side-effect of some other (legal and reasonable) command?

Reply to
Dave Platt

If this machine's computer uses a battery backup CMOS RAM then your problems could be just starting. If a lithium battery, then change it with the power on so you don't loose any settings (and very clever of you to record that info!), if Ni-Cad then watch out for alkaline leakage and again, replace with power on using an isolated tip soldering iron (batter or propane is easiest) if it requires unsoldering. Extend the wiring to it so it is away from any electronics...

John :-#)#

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Reply to
John Robertson

Just like early Bally SS machines....

Reply to
Terry Schwartz

As far as I know there is no way, oiher than flipping the parameter switch, to change parameters. And besides, it worked one day and then whenturned on the next day did not. Eric

Reply to
etpm

The machine does have battery backup. An alarm condition tells you when it is time to replace batteries. FANUC controls are very good at telling you when it is time to change batteries. Nevertheless I always change batteries on a schedule so the alarm has only happened once, shortly after I bought the machine. Eric

Reply to
etpm

Game Plan MPUs are worse for battery self-destruction. The battery is on the side of the board, not the bottom, so the eating is good (for the alkaline)!

John ;-#)#

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(Please post followups or tech inquiries to the USENET newsgroup) 
                      John's Jukes Ltd. 
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Reply to
John Robertson

Where I worked we had hundreds of devices that had microprocessors in them. For no reason we could tell every once and a while one might do something strange and would have to be reset. This may only happen once a year or so.

When memory chips first came out, it was said that the coverings of them might emit an alpha partical and flip a bit.

Reply to
Ralph Mowery

I figure it was a cosmic ray. Maybe my machine has a nuetrino detector in it! 1 detection in many years fits the bill. How many years I don't know but the machine has been around a long time. I could wrap the machine in lead to protect it but I don't have any two light years thick pieces. Eric

Reply to
etpm

When I was doing CNC repairs at Northrop Aircraft, I had an odd problem with a Pratt and Whitney Starturn lathe. They had these HUGE 3" x 18" helical wound resistors for the spindle braking. Because of the current, the winding wound bounce like a Slinky toy. Eventually breaking off the ceramic nubs on the form. So when they'd apply the spindle brake, the turns would short out and arc. Add that to the crap job the machine installer did with the grounding and you have a major problem.

So, one night, the operator is most of the way through making a 6" diameter hydraulic coupling. The machine forgot to recenter a boring bar and went to rapid retract. Nice, but it pulled the part out of the chuck while it was turning at a high rate of speed. After making 5-6 full loops around the inside of the safety cover, if finally found the sweet spot, exploded the glass and took off past the operators head and through the wall behind him.

On the other side of the wall, it found a 36" Blanchard grinder and hit the wheel, breaking it. The next thing to happen was a seriously off balanced grinder trying to hop across the shop until it ripped it's wiring apart.

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Jeff-1.0 
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Reply to
Fox's Mercantile

You have all the fun.

Reply to
jurb6006

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