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Cydrome Leader Cydrome Leader is offline
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Default A sign of dirty connectors?

wrote:
Greetings All,
One of my CNC mills has a problem. The machine, a Fadal 15XT, built in
1998, (I think), keeps showing an alarm for a malfunction the machine
can't have. There is a machine interface board that, among other
things, monitors for lube oil and air pressure with a couple sensors.
My machine uses grease instead of lube oil and does not use air in the
spindle oil mist system because my machine also has a grease packed
spindle. So there are not even sensors for the board to monitor and
report to the operator. Anyway, after the machine has been running a
while so that the electronics cabinet is warm inside the alarms start.
If the cabinet is opened and the board in question is allowed to cool
the alarms would stop. But then even the tactic of running the machine
with the cabinet open would not prevent the board from throwing alarms
after being on a few hours. If I turn off the machine and let it cool
for even 4 hours the board will still throw alarms. However, if I
remove the board and put it back in the alarms stop. After running the
machine several days the whole thing starts over again and the only
remedy seems to be removing and re-inserting the board. I have cleaned
the contacts with alcohol and "contact cleaner". The contact cleaner
is some type of chlorinated hydrocarbon solvent, the same stuff is
also sold as brake cleaner from the same maker. So after the long
winded explanation above I am wondering if dirty contacts could
somehow make the board run warm and cause the alarms. If that's the
case I'll buy some Deoxit or similar and try it out. Otherwise I'm
looking at about $500.00 to get a repaired board on an exchange basis.
The only boards available for this machine are as old as mine.
Eric


I'm not sure of what contacts and connectors you're dealing with, but
consider the solder to them may be bad. The wear and tear on a flakey
connector (if that's the problem) only goes up when you fuss with it more.

Bad connectors can get hot, if they're handing enough current. I've seem
them go up in flames once the arcing starts. There's nothing like
scrubbing black soot off circuit boards after the fireworks show is over.

Not surprisingly discolored, or melted looking connectors are always a
warning sign.

Intermittent problems with heat still point to connection problems, even
if on the PCB itself, and not the connector.

I fixed one board recently in a timer board that was "intermittent" that
had only 7 broken and bad solder joints. How it worked at all was a
mystery.