10M powerup-bad power supply?

[MackBMF]

Helllo to all. I have a Tree 310 with Fanuc 10M control from about 1984. The guy I got it from said that it just shut off one day. I ran power to it and the green LED on the input unit board comes on, I push the power on button on the HMI and the contactor pulls in, then kicks out right away and the red ALM LED comes on also. If I push power off on HMI the Red LED will go out. From all the similar posts I have read it seems that most knowlagable people would suspect that my power supply would be bad. What I can't find is a procedure for testing this without exchanging. I see that there are test pins on the bottom of the power supply but how could I test these if the control wont stay on?

[Al_The_Man]

This is the catch 22, there are quite a few types of Input units, but principally they check the system power supplies at power up and if they do not come up in a certain amount of time, it shuts down, so it makes it hard to assess where the problem is.
Fortunately there is a way by way of a service jumper across P1 & P2 of the input unit, this picks up RY1 or what ever is on the particular unit and prevents the shut down.
The only thing to be aware of is if the problem is due to a short etc, the power supply will remain across the short circuit.
Some input units also have a door interlock terminals that in most cases is jumpered out.
Al.

[MackBMF]

Al, I see that the door interlock is jumpered. I also see the P1 & P2 you are refering to, they are pin terminals. If a short existed and was causing this alarm, I would be cooking my power supply and maybe something else using this method. Is that right? To add to the information there are no blown fuses or tripped overloads. I know an electical engineer at a company in town who may be able to test this power unit off the machine, perhaps I should take that route.

I intend to strip the controller and sell it, but I would like to find out whats wrong so I don't sell someone a bad part. Is this risk worth it to diagnose the problem or should I just take it as the power supply is probably bad. Also do you know if ths control has fixed memory? It has been unhooked from power for 6 months and the D batteries in the back up are 8 years old.

[Al_The_Man]

I have used this method without any harm so far, it is just a cautionary note that Fanuc offer when using it.
There should be a list of parameters etc that have to be reloaded if they have been lost due to bad batteries.
Either hard copy or on disk.
Al.

[fanucman]

this is easy.. red light one input unit or on the power supply on mainboard?

i forget now but for the input unit.. remove all outputs and see if control comes up.. if it does then you need to trace it down to what output it is.. if you still get a red light then the input unit is bad..

if its a red light on the power supply do the same..

[alexfanuc]

Remove the connectors at the I/O board and see if the control will come up.
Sometimes there is a short.