820-00244 no display

Hello, we have an 820-00244 that came in for battery replacement. After the battery was replaced, we have a black display. We have tried a known working display and same situation. Display completely black, so its not no backlight. I checked, we have 5V (C8512) for a second and then drops to 0v, and 0.144v on Backlight IC (C8500). Pin 23 from LCD connector 0v. Any idea what can cause this. I connect to external display and that works. Also noticed KBD not working (worked before). Could it be related to i.e. a damaged keyboard flex cable? Will try another cable tomorrow as first I am backing up the data from this pile of trash.
 
SMC_LID = 3.2v

Some more info. I checked with another board and this display and it works. When I connect the non working board I did find EDP_BKLT_EN = 0v on the working board it is present. The issue is not no backlight though, as I have no image at all. Also when I connect to external display, keyboard did not work, but Trackpad I can feel clicking.
 
Last edited:

2informaticos

Administrator
Staff member
Same TP/KB work with the other board?

Backlight is the last to appear; image must come first.
You may have no backlight issue at all; find why there is no image.

Check if both 3V3/5V_S0SW_LCD appear at J8500 in the first seconds (when chime).
If yes, DP_INT_HPD should come high at same time.
 
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