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Old 04-18-2017, 05:49 PM   #22
eaarnoudse
Erwin Aarnoudse
 
Join Date: Mar 2016
City & State: Rijnsburg
My Country: The Netherlands
Line Voltage: 230VAC 50Hz
I'm a: Knowledge Seeker
Posts: 26
Default Re: HP ZR2440w backlight cutting out

I did some additional investigation of the power supply and it seems like that the LED driver IC and the LED strips in the panel are OK. I found something really weird in the primary part of the power supply. When I connect all boards and cables and I switch on the monitor, it stays dead. Ok, here is the trick. When I HOVER my screwdriver over the PWM IC (OZ531GN), the monitor and the LED backlight turn on. It looks like there is some capacitive "sensing" that activates the IC and the rest of the circuit. I will try to measure the circuit with my oscilliscope later this week.
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