[SRT Mike]

I have an LC40 and last week I was running parts and after a couple of hours of cranking out parts, I load the next bar and hit start and the coolant turns on but it just sits there.

Hit reset, nothing. Turned off the control and back on, didn't help. Turned off the whole machine and went to lunch. Came back and turned it back on and it was fine.

Today it did the same thing again... turned off the machine and almost immediately back on and it was fine for 2-3 more parts then it did the same thing.

I know the program starts when I hit the cycle start button because the coolant turns on. I opened the cabinets in back and I don't see any error lights on the spindle drive - only two green lights.

Any ideas what could be happening? It seems maybe temperature related since it happens only after a while of running the machine.

[underthetire]

Ok, you need to get a test program in. You need to narrow it down. Do one test with just moving the axis down and back. Then do another with turret index only (if it passes the first one), then if it passes that one, do one with spindle on/off. That will narrow down what we are looking for. The LC40's of that vintage have several banks of ice cube relays, my guess is one of those if failing. Pretty common now with the age of those things. Relays are cheap.

[SRT Mike]

Well, when the spindle refuses to start, I can click into manual mode and jog the axes fine. Actually the first thing the program does it move the turret back, then start the spindle... so the turret moves back, coolant turns on - then it just stops. It seems like the control is waiting for a "spindle running" notice which it never gets.

I think you are right about those relays - I've replaced a couple of 'em already... only thing is there must be 50 of them back there Any idea how to narrow it down? I am at the shop alone today but tomorrow I will have a couple people here - when my chuck clamp pedal was on the fritz, I could see the red light turning on and off on the relay when I had my helper press the foot pedal. I will start there trying to narrow down the spindle issue, unless anyone has any idea what relays to look at?

Thanks!

[underthetire]

Ok, some EARLY LC40s have a Yasnac/yaskawa 626 spindle drive. I have had issues with the relays on the top board. EASY way to tell is command the spindle, when it doesn't start, tap (not pound!) on the top board of the spindle drive with the plastic handle of a screwdriver. If it starts, its one of the little metal can relays soldered on the board.( this is only if it has the Yaskawa drive BTW)

[SRT Mike]

Ended up being a relay after all.

There are two that operate the chuck, one is "chuck open (command)" and one is "chuck open". I guess one just sends the signal to the control, the other does the actual opening.

The former has an LED on the relay that was working - but I replaced it. The latter has no light, but I figured out it was that relay, replaced it and it's working great now.

Thanks for the help!

I am gonna start another thread on getting some servo drivers repaired

[underthetire]

There is a place in the us that repairs them, I'll see if I can dig up the info.

[SRT Mike]

There is a place in the us that repairs them, I'll see if I can dig up the info.

The servo drives you mean? When I was doing Google searches, there were tons of places that will repair them... but they want $1000 or so for the job. I can buy LDU-600's on Ebay for $400-500 or so... now granted you don't know how long they will last, but it's a lot less than $1k.

Also, I don't really use the other axes on the machine... I'm looking to drop maybe <$1k to get all three drives working. I design electronics for a living, but nothing as power-hungry as these servo drives, so I'm slightly out of my element repairing myself, but I wouldn't mind starting with the transistors and see if it works