Fadal 4020 keeps shutting down

[matt_d]

Hi all
I have an old 1995 VMC4020 that I picked up cheap on e-bay. It is not in to condition all things considered. I saw it on ebay and it was on my floor running 4 days later, and up until the last few weeks, it was good.
The problem has developed over the last couple of months and is now a real pain in the butt.
Initially, it was just the machine cutting out on startup, and it would take maybe 2 or 3 presses of the CNC ON button to get it started. Then it started to cut out on cold starts, and now it is cutting out during operation. It is worse in the morning, and by midday it runs OK.
I thought that it was the ballscrew bearings as they all were pretty noisy and clunky, so I pulled them all and got them reballed, and replaced the support bearings (nightmare to source).
So all that done and to problem is still there. After thinking logically, it would seem to be more of a power supply issue than an overload issue, as the machine just cuts out, no alarms, no blown fuses.
So, has anyone had similar issues? Any suggestions welcome cause I need somewhere to start. I have no manuals at all for the machine so am shooting blind on that front.
Cheers
Matt

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[hanermo]

Fadal manuals are online someplace iirc.

Usb-connected volt meters, logging, maybe 60€ each, are available.
Get 2 or so, track power from whatever fails, upwards till mains power.

It might be main control stuff..
or just as well anything silly, like say a coolant pump, air-pressure solenoid, error-signal, or maybe a short to ground from one of the ancillaries, causing a power-down.
Try to find a way to make it fail reliably and fast.

Then keep disconnecting/bypassing stuff till it does not fail.
Work on power-2, binary,
Repeat 2-3 times.
Always disconnect/connect twice the stuff, no more or less.
Then work backwards, reconnect half the stuff from the failing block-o-stuff.

Do not guess.
Repeat.
Re-test.

Sometimes, one-affects-another unrelated.
A good rule, always, is replacing electrolytic caps on power supplies, transformers, similar.
Likewise, cooling electronics.
Cool electronics = 20+ year lifetime.
Hot, 1 year or less.

Your issue could very well be heat, with a failed fan somewhere.

[jbranting]

Technical Docs | Manuals & Diagrams | FadalCNC.com

There are the manuals and other documents that are helpful.
I had a similar problem, it ended up being an ELE-0070 solid state relay that was failing. Good luck

[matt_d]

Thanks for the fast replies guys.
I will check all the cooling fans and give the whole thing a good clean up.
Relays would make sense for what is going on. I might change them out and see how it goes
Cheers
Matt

[warrenb]

Technical Docs | Manuals & Diagrams | FadalCNC.com

There are the manuals and other documents that are helpful.
I had a similar problem, it ended up being an ELE-0070 solid state relay that was failing. Good luck

Ditto on the relay. My FADAL did something just like the problem you are describing and it traced to a bad relay.

[carbidecraters]

That can also be a dead and dying power supply.