fANUC OT Mori Fuse blows

Mori Seiki AL-20 with Fanuc OT-Mate control. Fuse "FX14" (1 amp) is randomly blowing after about 30-40 hours. Mainboard, right next to the
power supply. Microfuse. Is there power supply voltage that is just a tad bit high?
Anyone seen this in the past?
ca
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AL-20 EX OFFSET CURRENT V
Need to have the motor megged if it checks ok you will be replacing the servo amp.
DaveB
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On Fri, 12 Sep 2008 23:01:26 GMT, snipped-for-privacy@nt.org (DaveB) wrote:

Sorry I thought you had alarm #20 DaveB
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clay wrote:

Fanuc error 905. External 24V line. Gee, only the whole damn I/O & control side is 24V. How many switches etc could that possibly be? AND it is very intermittent... Even Fanuc said good luck finding it. I better get a whole box of fuses, or wire in a 1 amp breaker....
Went weeks using a 1 1/4 amp emergency fuse while waiting for the special Fanuc 1A Microfuse to show up, so..... Typical current draw is 0.21A, so obviously it is spiking randomly.
Anyone have some suggestions on what it is most "likely" to be? There are no obvious symptoms. The fuse blows while the machine is idle.
ca
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clay wrote:

You might have an intermittent short in the oiling circuit. That is something that probably cycles on a timer regardless the motion on a machine of your vintage. Cooling fans and chillers are also relay operated.
--

John R. Carroll
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a
Make up some nice long test leads and put a dc ammeter in series with the fuse---carry it around with you while start jiggling switches wires cable connectors etc.
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or stick in a piece of brass round stock and wait for the magic smoke to point out the problem.

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Gunner Asch wrote:

Gunner:
    I think you should of put a smiley at the end of that sentence. Never can tell who might actually try that as a last resort to replace the offending part. LOL
--
BottleBob
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wrote:

<G>
Ive seen it done before.
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wrote:

Clay if you have a ladder diagram for the machine then you should easily find the 24v power supply feed on the first few pages where the 3 ph mains etc are described--there you will find a pointer to the page number where your 24 volt ladder starts and thes pages will show a definate ladder resemblence to an actual ladder with 0v on one side and 24 on the other, find yourself several suspect refrence points and then place some additional inline fuses, does not matter if they are on the zero or the +24 side.
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