Why does my display have artifacts on boot?

Hello All,

I own a HP Pavilion dv6z-3000 notebook, which after previous issues has been sitting in my closet now for over a year. I took it out earlier this week and starting working on it. I fixed the main issues, but now I am faced with a new issue. My display has lots of dancing red artifacts (shown here) only on BIOS screens, and when using the low-performance GPU. Which would lead me to believe it's the GPU, and hence replace the motherboard. However, when I plug in a external VGA monitor, the artifacts are gone! This is puzzling to me, because I believe if it were the GPU, I would see these artifacts on my external monitor, but I don't! If it were the display connector I would see them with both the high-performance and low-performance GPUs, but again, it is not so! So my question for you is, what is more likely problem, the motherboard, or the display connector? While the artifacts are on screen, they seem to be sensitive to any touch on the display connector. I've also disassembled the whole thing, including the display enclosure, reseated the display connectors, it seemed to work for a few hours. Then I rebooted and the problem persisted. It's also worth noting that the display connector runs right over the fan/heatsink, and my laptop runs a little hot at about 59 C while idle. Which could also affect the GPU. I'm confused! Any advice would be greatly appreciated!

Cost of motherboard: ~$100 USD from eBay

Cost of display connector: ~50 USD from HP

Thanks,

Marc