15M won't start

[gtrdavid]

I have a Fanuc 15M. My problem is, it will not start up / boot up. It turns on some days and some days it does not. When I press the start button you here the relay engage momentarily the fans start to turn on then it just stops. On what I believe is the power board there is a Green LED light and a red Alarm LED both lit. When I press the off button the Green LED stays lit but the Red alarm LED goes off. Does anyone have any suggestions?

[underthetire]

Usually that indicates a short in a 24 volt line somewhere.

[memoryman]

I agree. Could also be the power supply, some boards, shorted suppression diodes, wiring shorts and more. Where are you located?

[tc429]

90% of the time its coolant in a limit switch...look for the dirtiest switches, they are usually a good place to start.
get a good DVM that will read to .01 ohm, poweroff, start checking ground to your input terminals, the lowest one is usually the culprit... a normal meter its hard to see as all the OT/Decel switches are normally closed will read under a ohm from one to the other, but using low ohms scale, you can pick up the lowest one because of the resistance/length of the wires.

it can be anywhere, even just a bad cap on a 5v/15v supply- but limits or busted wires are usually it. sometimes you can even just sniff around- the smell of water etching away at anything electrical usually has that 'burnt solenoid/varnish' smell to some extent

[gtrdavid]

memoryman, I am from Massachusetts but currently an in ChangYi China. So getting information in English around here is not easy. I want to thank you all for your help.

tc429 I follow you about the DVM and process. I will trace and check all the wires first then dig into the electronics. Please forgive me I am new to this, where would I find that limit switch you mentioned?

[tc429]

China? let them fix it

switches for overtravel/decel are often a Balluff or Euchner multi-plunger switch that trips at the home/end of travel on each axis, they often get coolant in them and short to ground... sometimes mounted under way covers.

[gtrdavid]

yeah I wish , it's been a struggle, but Thank you so much! I know exactly where those limiters are. I will check that first thing in the morning.