Hi,
I'm working on 820-3787 which has problem with disorted image on internal screen. First, when customer came in image was OK. The only problem was that it wasn't passing login screen or was turning off while loading system. I thought it's typical VCORE problem. After one day laying on shelf waiting in queue I took it and turned on. The image was disorted, showing yellow rectangles while loading system and mixed colours on login screen. I took board out, it has no signs of liquid, no missing SMD components. I resoldered U9300 just in case, but with no changes. I've tried another good screen - the same thing. After disconnecting internal screen I get image on external monitor and it's the same disorted like on internal screen. My first bet was damaged VRAM, but later I've measured coils on GPU VCORE and readings seem pretty low. Both PPVCORE_S0_GFX_PH1 and PPVCORE_S0_GFX_PH2 have ~1,4ohm resistance to ground (I have another board with damaged PCH and it reads 27ohm). With U9300 removed I get the same value. I bet dead GPU. Should I give it a try and replace VRAM before touching GPU?
PS. I've noticed that the plastic "lever" which is locking left fan flex in connector is missing and fan doesnt spin since I don't press the connector. I guess beacuse left fan wasn't spinning GPU just got fried because of temperature.
I'm working on 820-3787 which has problem with disorted image on internal screen. First, when customer came in image was OK. The only problem was that it wasn't passing login screen or was turning off while loading system. I thought it's typical VCORE problem. After one day laying on shelf waiting in queue I took it and turned on. The image was disorted, showing yellow rectangles while loading system and mixed colours on login screen. I took board out, it has no signs of liquid, no missing SMD components. I resoldered U9300 just in case, but with no changes. I've tried another good screen - the same thing. After disconnecting internal screen I get image on external monitor and it's the same disorted like on internal screen. My first bet was damaged VRAM, but later I've measured coils on GPU VCORE and readings seem pretty low. Both PPVCORE_S0_GFX_PH1 and PPVCORE_S0_GFX_PH2 have ~1,4ohm resistance to ground (I have another board with damaged PCH and it reads 27ohm). With U9300 removed I get the same value. I bet dead GPU. Should I give it a try and replace VRAM before touching GPU?
PS. I've noticed that the plastic "lever" which is locking left fan flex in connector is missing and fan doesnt spin since I don't press the connector. I guess beacuse left fan wasn't spinning GPU just got fried because of temperature.
Attachments
Last edited:
