[SSI]

Getting an alarm.. U796 Over run. PLEASE HELP

[Royster]

The alarm points to either a broken wire on an axis stroke limit or if this is a CX machine or similar it could be a SIFA card problem

HTH

[eroprel]

i'm having the same alarm on my fx20 any sugestions??

[Royster]

Hi, We have 8 mitsy EDM wire machines here. They've had all symptoms. Check the alarm page for which axis it points to! then you can simply find the cable. My bet is Y axis and the cable runs along the length of the machine and has probably got trapped and cut through. At the worst the SIFA card in the NC cabinet needs attention this could cost around £500-£800 (£1000-$1500) to repair. If you can't find a broken cable you'll need a service engineer to diagnose. HTH

[Makrep]

If on the alarm screen the alarm tells you all axes are overrun, look at the PD21B in the control cabinet, is the red LED on at the top of the PD21? if so, disconnect the grey honda connector on the MW712, does red led go off? if so then it is definitely on the machine or the SIFA PCB? Let me know what happens.

[CLATHAM]

We have a FA20s i am getting same alarm. I have taken all the covers off, none of my 5 switches are hitting. All wires look good back to electrical cabinet. Any suggestion.

[Makrep]

It could be the fuse on the UPS pcb, do you know where that is situated?

[DarkKazak]

So, I also got this problem on Mitsubishi FX20. At one point, I got an error u796 Over run. I tried all the tips in this thread, but nothing worked.
I tried to fix it myself and it worked. In my case, the contact group was exposed at the back of the machine, and pieces of wire fell on it. I blew everything with a pneumatic gun and the error disappeared.

[TZak]

I got the same error on my fx20 and every time I touched off a part my main power would trip, controller would stay on. That problem seems to have gone away but now I don’t get any contact with my wire. Everytime I try to touch off a part it’s showing no contact the light is off all the time. Usually the problem is reversed and you can find where the contact is. Wondering if something inside the cabinet went or if it’s still a broken cable somewhere.