Mori Seiki AL-20 with Fanuc OT-Mate control. Fuse "FX14" (1 amp) is randomly blowing after about 30-40 hours. Mainboard, right next to the power supply. Microfuse. Is there power supply voltage that is just a tad bit high?
Fanuc error 905. External 24V line. Gee, only the whole damn I/O & control side is 24V. How many switches etc could that possibly be? AND it is very intermittent... Even Fanuc said good luck finding it. I better get a whole box of fuses, or wire in a 1 amp breaker....
Went weeks using a 1 1/4 amp emergency fuse while waiting for the special Fanuc 1A Microfuse to show up, so..... Typical current draw is
0.21A, so obviously it is spiking randomly.
Anyone have some suggestions on what it is most "likely" to be? There are no obvious symptoms. The fuse blows while the machine is idle.
You might have an intermittent short in the oiling circuit. That is something that probably cycles on a timer regardless the motion on a machine of your vintage. Cooling fans and chillers are also relay operated.
Clay if you have a ladder diagram for the machine then you should easily find the 24v power supply feed on the first few pages where the 3 ph mains etc are described--there you will find a pointer to the page number where your 24 volt ladder starts and thes pages will show a definate ladder resemblence to an actual ladder with 0v on one side and 24 on the other, find yourself several suspect refrence points and then place some additional inline fuses, does not matter if they are on the zero or the +24 side.