Problem- VF2 power board Fuse blown PIC

[LakesideMachine]

we just picked up a used VF2 and wired it up. On the power board i noticed a blown fuse indicator. it is a 500Ma fuse. the machine starts up, moves, spindle runs, changes tools....etc.....the blown fuse doesn't seem to bother it. What is this fuse for? the fuse that is blown is the middle one in the pic with the amber light to it's left in the upper right corner of the board.

Any ideas??


I did change it out and it blows right away......


http://www.lakesideguns.com/webstuff/haasfuseblown.jpg

[rrbmachining]

According to my service manual fuses 1 to 3 will blow if the incoming 3 phase voltage exceeds 285v ac. They are used to feed a varistor network that feeds the 220 to 24v transformer. When one of these fuses blows it drops out relay K1, but Im not sure yet what relay K1 does

If you post an email address I can send you the wiring diagram

[rrbmachining]

Just found it K1 is the main breaker for the incomming supply

[Masher Mfg]

Be sure to check incoming voltage ( top of main breaker ) then move transformer taps to match recorded voltage. Once you get it set, measure voltage when no and many other machines are running. If the no other machnines running voltage is near the bottom of the range and the other running machines measurement droops to the next lower tap, use the lower tap.

Past that there may be a circuit board issue.

[LakesideMachine]

incoming voltage is appropriate for the supply terminals. the legs are within 1.5 volts of each other. i have the incoming voltage in the right volt range on the transformer. The K relay has the right voltage going out of it too.....

everthing runs on the machine, it does all it is suppose to do....no alarms or anthing....

What is this middle fuse holder for anyway?

The machine is wired for 4th axis, but I'm not using it.....maybe something for that??

[rrbmachining]

Fuse 1 is connected to L1, fuse 2 is connected to L2, fuse 3 is connected to L3 on the supply side. On the machine side of these fuses are 3 varistors which are connected to ground. Then there is another varistor network connected phase to phase. From this network there is a tapping off to the auxiliary supply transformer. This transformer should have between 195 and 260v ac on the primary. and 24v ac center tapped to earth on the secondary. The 24v supply goes through the power on and power off buttons on the pendant to energise relay K1