I'll check out the cup washer issue.
I already rebuilt that valve - It was very clean and found no issues with it.
I think the key is that the output of that valve is getting constant air into OUTPUT side of the valve. The line should not have any pressurized air in it until the valve opens and gives it air, so why does it have constant air ? Did something blow downstream that is bleeding air into this line ?
Look at the cup washer under a magnifine glass, you might see a small tear on the top. Mine had one couldnt even tell.
contant air is because a valve is always on. usually you have issues with the high and low gear change always being on. rarely Ive seen the tool problem.
now assuming what your saying is whats happening other things to look at are the electonics side. the mag switchs mainly
, it could be as simple as a relay( they dont go bad often , but they get dirty and need to be cleaned. its a little switch on the board just to the right of the transformer. youll seems some small 1/2" wide by 2" long boards plugged in. you can switch them and see if you still have an issue.(one way to tell)
the coolant mist from the fans always gum those up. usually on the back of the main board they plug into. but also the relay boards as well.
they were part number ELE-OO70 yours is a newer mill so I think you have the solid state(black covered ones) ones, the ones in the older machines where just a open green pc card with some electronics on them. there on the main board to the right of the transformer and at the very bottom of the cabinet.
the air on all the time might be a combination of a few things as well, Like I said I dont ever remember any of my fadals dropping tools just not saying it couldnt happen. the low and high gear change might be the cause of that. as that might be another problem.
you said you rebuilt that valve WHY? what was going on?
did you recently do any work to the machine and valves then have the problem? if you did again why were you and what was going on.
the mac valves go bad alot and fast if you dont have a dryer in your air system and I dont mean a paper one I mean a real one, if you ever spit out water those mack valves will fail.
was the machine running good than just drop a tool?
did you hit a button and it stuck or did it just drop all by itself?
reason I ask is if it dropped by itself that usually means you had made electrical contact somehow some way to drop the tool(but not always) why I say also look at the relay chips ELE-OO70 and make sure everything is clean.
so to clean them do like what I said above.
while the air system in a fadal looks like a cluster fuck its pretty darn simple to figure out.
oh yeah one other thing, check to make sure your draw bar plate is going back up, if its not that is a problem that is also a problem with the valve that has the cup washer in it.
to check mack valve you can push the little plunger in (on the right side) and let it go.
find out the valve that is seeping air follow the wires to the board that will tell you what its for.
sorry my reply is scattered all over the place, was looking for better pics and then something else would pop into my mind.