Viewsonic N3252W No display

[benV]

Hi everyone,

My Stepfather gave me his Viewsonic N3252W to (try) fix it. Suddenly, one day, the display went off. The power button stay green and the sound work but that's all. I already replaced a NKS N3856VG chip on the under side of the power board because the area around was brown (heat) and because i found some people talking about this possible faulty piece.

After that, i took pictures of the board and i made measurements. Here they are:

To the logic board CN801 :
number color power off power on
1 black 0 0
2 black 0 0
3 black 0 0
4 black 0 0
5 yellow 0 2.49V
6 yellow 0 2.49V
7 red 5.15V 5.12V
8 red 5.15V 5.12V
9 red 5.15V 5.12V
10 brown 60.8MV 3.49V
11 orange 0.623V 4.86V
12 blue 6.2MV 4.87V

To the inverter board (i think) CN701 :
1 light gary 6.2MV 4.87V
2 gray 0.62V 4.87V
3 purple 0 104.7MV
4 blue 0 104.8MV
5 green 0 104.9MV
6 yellow 0 105MV
7 orange 0 0.1MV
8 red 0 0.1MV
9 brown 0 0.1MV
10 black 0 0.1MV

I hope that those numbers will help you to help me ;-)
Thanks.

[paulstef]

Re: Viewsonic N3252W No display

I have a 3752w right in front of me. Completely different boards but same symptom.

There seem to be no voltage (about 24V) going to the inverter board. That's connector CN701 according to you.

You also need to find out which signals control the backlight (assuming it's the backlight that doesn't turn on). CN701 pin 1 and 2 look like good candidates.

But first you need to find out why there is no 24 or similar voltage. Looks like a problem on the power board. Check for visible damages, cold solder joints, check FETs and diodes first.