820-00165 no backlight

[vinzmt]

hi to all
i have this logic board with no back light, image is present.
unknow istory.

on q7707 pin 5 EDP_BKLT_EN found 3.3 v, pin 1 gnd damage, pin 2 BKLT_PLT_RST_L only 0.08v (but is 3.3 on r2088 pin 2)
remove q7707 and find this

any suggestions?
thanks

[mon2]

Post voltages for Q7706/07.

[vinzmt]

q7706:
1:0v
2:0v
3:8.3v
4:8.57v
5:0v
6:0v

q7707 without cip
2:0.004v
3:8.2v
4:0v
5:3.13v
6:0v

[mon2]

Remove all power. Meter in diode mode. Short your meter probes and you should hear a tone beep.

Connect one meter probe (either color) to R2088, pin # 2 and other meter probe to BKLT_PLT_RST_L on the removed mosfet PCB pad. You should hear a tone beep. If you do not, then the PCB trace is broken.

Repeat with R2088, pin # 1 - same tone beep should be heard.

[vinzmt]

trace is broken. What do you advise?

[mon2]

Locate a thin insulated wire and solder it point to point. Share the pic of the wire and joints if in doubt.

[vinzmt]

Ok, tomorrow i try, thanks 🙏🏻

[vinzmt]

I found this wire, does it seem too big?

[kevingill]

Don't think the picture made it on to the website

[vinzmt]

[reformatt]

If you were fixing a car or something, that might be appropriate. But way too big for this application.

From the boardview, the connection to Q7707/2 is from a via underneath that area. I'm guessing its to the test pad, which has been eaten away. Since there are no other connections on that side of the board, you'll need to run a jumper that wraps around the board from one side to the other. You will need 0.1mm enameled wire plus some way to tack it down. I use dabs of conformal coating (which you cure with a UV lamp).

[vinzmt]

I don't have this material at the moment. I'll get it and try it, thanks