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Old 06-07-2011, 07:21 PM   #27
jackr
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jackr has learned how to buy an e-book online
 
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Quote:
Originally Posted by ivanjt View Post
OK, I have a little time while the server racks are installed.

Something doesn't seem right here, I'm not saying your measurements are wrong. just that the backlight should work since you are getting the nominal 5v at point 1.

Can you check that you get the same voltage (4.88v) at the + terminal of the LED array.

There may be two other explanations, Pulsing the supply to a higher voltage or they are switching the negative supply line. The first is possible but there is no logical reason for the second.
The closest I can get at the moment to the led's is where the led array ribbon is soldered to the lcd ribbon on the display. I have run 7.79v through it before and got the leds to light up; I also tried 6.47v but the leds didn't light up. 4.88v is present @ where the ribbon is soldered.
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