Screen goes dim during fresh MacOS install

Hey everyone,

I wanted to tell you all a story today what happened on a Macbook mid 2010 13” unibody model.

Anyway’s, the customer brought it to me for repair. I changed the HDD to a SSD. So that went well…. I made a bootable Yosemite USB drive.

I went to boot it via OPTION command on startup. The setup loads across with the Apple with the loading bar. Loads perfectly… Now it goes to the start screen to install MacOS Yosemite and the screen randomly goes completely dark.

I knew the installer was still on because I heard voice assistant and if you flash a light over the screen, you can see a very dim image.

Anyway’s, I played around the macbook for a few minutes (rebooted and tried again) did same thing over and over. I found out placing my finger over the IR Sensor at the bottom right of the MacBook, the screen will come back (full brightness)… The HD cable/IR sensor runs together and that IR sensor only works for IR remotes…. I ended up placing a piece of black tape over the sensor and the installer completed without a screen dim issue.

Now…. If anyone can tell me, why would that sensor cause a screen to go dim? I thought the ambient sensor would have caused that issue but I put my finger over that (near front camera) and it didn’t come back. I was told the HD cable in this model are prone to fail and cause issues with hard drive not booting (not cause screen to dim)… After the installer, i removed the tape and the screen stays on without dimming…

Has anyone ever has that issue? Needing to place a piece of black tape over the IR sensor on the from of the system to get the screen to work?

I will end up replacing the cable anyway’s.