5920 black screen after uninstalling display drivers

I recently installed an hd 3650,and it was all working fine. However, I attempted to uninstalling drivers through device manager, don't rebooted my laptop as I wanted to go back to stock drivers.

Now, I just get a black screen. Laptop still boots, but I can't do anything with it!! Please let me know how I can sort this out

Have tried my old graphics card too, an nvidia, which displays a picture until it boots, then goes black screen. Have I screwed it up??

Right - after some fiddling about, I've realised that for some reason, my screen stays completely black until Windows boots - as soon as the mouse cursor appears, the screen comes back to life.

Every time I restart, it's always blank until Windows "starts" (i.e. at cursor appear), and then it's fine.

Any ideas?

 

Most likely your D-Sub or HDMI connector has a short, causing the graphics card to think that an external display is plugged in.

 

I have found the following thread that describes my problem, with post number 12 offering some insight:

"All graphics cards/chips have two modes they work in. The first mode is a VGA mode that is not dependent on any special installed drivers. This mode always works when the computer is first started. After the computer enters the operating system then the advanced features of the card/chip are activated by means of installed drivers."

- Blank screen UNTIL windows loads

I'm thinking that when I uninstalled drivers through device manager, somehow I managed to "wipe" the default VGA setting from my card. If this is possible, can I re-flash my 3650 to contain its VGA settings?

 

That is definitely not the problem. Installing or uninstalling a Windows driver won't write anything to the card's VBIOS ROM. Accidentally uninstalling the VGA driver will cause the opposite error (correct display on boot, then black screen once Windows loads).

More likely it's a coincidence - one of your external display connectors has a short. Try plugging in an external display to see if you have BIOS output on it.

 

I connected a monitor to VGA output and it worked perfectly... What does this mean??

 

That confirms my theory - either your VGA or HDMI port has a short. Check with a multimeter.

 

I shall do. Can this be fixed?

 

Yes, if you have a soldering iron. Possibly even without one, if it is caused by an object stuck in the HDMI port (the usual cause).

 

That's strange though. My HDMI port works perfectly... can you elaborate further on what I should be looking for? :S

 

Measure the voltage on pin 19 (Hot Plug Detect) of the HDMI socket. It should be low (close to 0). Chances are, it will be high, close to 5V.

Your HDMI port still works because pulling pin 19 high is the standard method of indicating that a HDMI device is plugged in. With pin 19 high, the 5920G turns off the internal display and outputs image to the HDMI port.

The reason why you still have image in Windows is that Windows is somewhat smarter than the BIOS, and it also checks for a valid DDC signal (in addition to pin 19 being high) before switching to the HDMI device.

 

Thanks. Can you advise on how I should fix this? Is it a case of replacing the HDMI port, or re-wiring it? How do I get to the port, and what should I do?

Thank you

 

Disassemble the machine, and look for a short on the traces leading to the HDMI socket. Also, try desoldering the HDMI socket and checking if the short still persists on it - if so, the socket itself is broken, replace it.