2012 MBP - very slow screen appearance at start up

[planemechanic]

My 2012 MBP screen is acting up. It can take as long as 15-20 minutes before the screen appears. I know the laptop is working because I can see the password screen on a second monitor. Any ideas? TIA

 

[Audit13]

Possible virus? If it's a mid-2012, could be a bad hard drive cable. Failing drive?

 

[planemechanic]

Possible virus? If it's a mid-2012, could be a bad hard drive cable. Failing drive?

I ran three different virus checkers, and I have a 1tb SSD installed. The computer is on, as I mentioned I can see it boot up on an external monitor, but the screen attached to the laptop is black. It eventually comes on, then will work for days or weeks if I don't reboot.

 

[DeltaMac]

15 or 20 minutes before the screen appears?
Every time?
Have you tried both hardware resets (PRAM, and SMC resets)
Do you normally keep a monitor attached (so you have a second display), or did you just try that as part of your testing?
On that long wait, try shining a bright light/flashlight into the screen, to see if there are any icons or menus, or the dock visible (or just the login screen). Maybe it's just the backlight not working properly.
This can be the display panel, or the logic board. My bet would be on the LCD panel.

 

[ZapNZs]

Does this behavior happen when you disconnect all cables from the MBP?
Does this behavior happen only on startup, or also when coming out of sleep or hibernate modes?

Has the PRAM/SMC reset, Apple Diagnostics, starting into safe mode, and/or a OSX reinstall been attempted already?

 

[Fishrrman]

I'd suspect the ribbon drive connecting cable inside.
Cheap and easy fix.

 

[planemechanic]

I'd suspect the ribbon drive connecting cable inside.
Cheap and easy fix.

I doubt it is a ribbon cable, as the display comes on and will stay working for days or weeks, until I reboot.

 

[planemechanic]

One added issue, the slow screen appearance is not just at start up, it happens sometimes when waking from Sleep.