Fanuc 18i-mb5 BAD Connections / Relays??

[JoeCraftsman]

We have a Fadal VMC4020 with a Fanuc 18i-mb5 Controller. We bought it used.

Occasionally the machine just stops wherever it is whether it be a rapid motion or during a cutting operation. The error flashes so quick you can't read the error message.

We figured out finally that it is connection issues. Tightening here and there. Now, The relays (A row of about 9) are acting flaky.

Looking for anybody who has had similar issues with this controller and any recommendations?

Thanks!

[Al_The_Man]

If all 9 appear to act up in unison, then first I would suspect a intermittent connection on the common feed to the relays.
Have you identified the function of each output?
This may give you a clue as to what alarm is flashing, although I would have suspected an input to cause an alarm, the controller usually does not know the status of the outputs after it has left the connection unit.
This is why I suggest identifying the output functions.
Usually the only other way all 9 would drop out together is if they all have a common logic bit in the ladder that changes somehow?
Al.

[JoeCraftsman]

Where we once had loose wires here and there, it now apears to just be in a hand full of relays occasionally. One realy works but the LED does not light up. Another, after the machine has stopped, will 'jump' back & forth making connection when you tap on it! A third relay, not possitive for sure that it has problems, has 'smoke-like' markings on the housing near the contacts.

I've ordered three new ones and have taken notes of the behavior of the different relays. Odd thing, the machine stopped 8 hours ago today from the relay that makes random contacting when you tap on it to another slot that does not seem to be used much if at all... Been working fine all day.

My guess, after some more serious hogging one of the other relays will act up again!

Thanks for the reply... Was not sure if this is common behavior with relays or fanuc controllers in general.