Fanuc power unit problem

[sbp]

Hi every one;
We have a Fanuc 6M controller with power unit
type:A14B-0061-B002-02.Our problem is that the
machie will not start to work when we push the ON(start)button.
The main relay behind the controller will be activated and ,soon after, deactivated and the red ALM(alarm) LED on the I/P unit board
(A20B-0007-0340-06A) will turn ON.
BUT WHEN WE PUT A READING LAMP NEAR THE POWER UNIT FOR
ABOUT 5 MINUTES BEFORE START(I HAVE SHOWN THE AREA ON
THE ATTACHED PICTURE),THEN EVERY THING WILL BE OK !!
1-Does Aaybody have exprienced this problem?
2-Does anybody have schematic diagram(circuit diagram) of power unit?
Atleast the diagram of the area that we have problem in there.
3-In the attached picture I have specified 2 capacitors which will
get to hot when the machine is working.It seems this is not normal,
Am I right?

Please help us what is our problem.Is there any element or part
in Fanuc 6M to be sensitive to enviroment temperature(and our problem
is of this kind)?Do we have any problem regarding over current problem?

Thank you in advance.
Bahmanpour

[Al_The_Man]

I think those 'Capacitors' are actually resistors? At least that is what it appears you have pointed to.
The symptom you have sounds like a classic symptom of short on the DC output, most likely on the 24vdc, I would disconnect the 24v connections on the RH side of the PS one at a time and see if it stays on.
The last one I had, was a shorted 5v regulator (24vdc fed) on the video board.
It can also be limits switch etc shorted.
Al.

[sbp]

Thanks for your reply Al The Man but if we have Dc shortage or
24V problem or limit switches fayulty or any other probelm,why the machine
will start to work after we warm up the specified area on the PS unit?
What do you mean by "the capacitors are acually resistores"?
Do you have the schematic (circuit)diagram of this section?
WHY WE DO NOT GET ANY ERROR MESSAGE AND ALARMS FOR LIMIT
SWITCHES,if they are supposed to be faulty?

[HillBilly]

There is a good block diagram of that unit in the maintenance manual.

I have put together a 15 piece kit that repairs 90% of the problems with that unit. The price of the kit is $30USD + shipping.

Darek