Kervyn
Im getting power to the computer.
but no display.
fuse is good.
just before this started,the alternator 25 amp fuse would pop.
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78buckshot
Kervyn, I would start by diagnosing why the fuse blew, if we are going to be any help we need more info about the unit your working on. Model and serial at the very least.
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Kervyn
Fuses are good 12 volts goin to the board. 
0066800 model
8600428 serial
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Peddler
It is possible the bridge rectifier in the field flash circuit failed and allowed field DC voltage from the voltage regulator to be pushed back into the DC system.  This could be 20 or more volts which could have gotten to the controller.  I have never seen that alternator fuse blow so something interesting happened.  Did the battery seem alright?  When you have that high DC voltage pushed back into the system the battery will absorb it for a while but that would ultimately end badly.  How old is this unit, any other unusual events recently? 
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Kervyn
So i tested the 15 pin the ground pins on the 32 pin plug ro the controll box.Voltage was good ground was good.
its my understanding  that my computer bit the dust.
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Peddler
Maybe it did bite the dust, pretty rare, but if it did why?
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Birken Vogt
I don't know what the problem is but I have had that 25A fuse blow on more 22 kW units than I can count.  Customer calls, dead unit, I find out which model it is, tell them check the fuse, they say it is blown, put a new one in and it will be fine again for months/years.
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Gray
I must agree with Mr. 78buckshot (although for anything serious I have been know to use Breneke hard cast slugs).

It would seem to be imperative to know the source of the fuse failure.
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murphy
Did the fuse "blow" or did it suffer a fracture.  Fuses mounted horizontally, that carry a significant percentage of their maximum current, will get warm and expand so gravity makes them sag.  Continued heating and cooling over time results in a metal fatigue failure.
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Gray
Murphy,

Excellent piece of information! I have never seen that published anywhere else.
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Kervyn
Can i get my computer repaired?
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Peddler
There is a company in Lancaster PA called Flight Systems that works on some boards and controllers, you can google them and they may be able to help you.
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