Hi,


A friend has a fancy All in One PC,HP610
Black screen..always..boot included
No VGA or HDMI out.
Turning it on ,it sounds ok from loudspeakers during loading,the typical
Windows start sound is clear.

In a repair shop after 30 minutes the diagnosis is "motherboard to
change"...not less than 350 euros,a big cost.

I said to him wait and bring it to me,because by me
1)I don't think they even opened it
2)The GPU,that is likely to be fault is on a 80 euros removable board,not
a BGA on motherboard
3)At least the LED backlight inverter deserves a check

Once opened i check the inverter,looks like a step up..one inductor,one
diode,capacitor on out
(Cout=2 x 10 uF 100V).Vin=19 V..but Vout=0V
Ok,supposing the inverter is KO,i want anyway to turn on the LEDs,to check
if some image is present on the display.
So i disconnect inverter input,and i apply voltage to Cout from 0 to
90V,with 10 mA current limit,but Iled=0.
Is there a opened LED?Maybe.Is the capacitor connected to output connector
os some burned tracks?
Positive is connected,but negative don't.The negative terminal of Cout
goes to PCB GND,but GND is not connected to output connector.The only path
is across the metal columns supporting the board.
A bit odd.

What is your opinion?Thanks.

Diego

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