What did I break on my phone?

[omerfbingol]

So, I was trying to hard reset my Lumia 925, halfway through the job, I got bored and started to play with circuit boards at the back, under the battery cover. Either I short-circuited something or the phone went bad somehow, the display gone black, no lights on the navigation bar. Then I tried to reinstall ROM with Windows Device Recovery Tool, and it recognized and flashed phone succesfully-minus the display. It is still off, and after multiple ROM flashes, the display won't turn on and yet I can browse files on the phone when it's connected to PC and it shows up as Windows Phone, like nothing's wrong.
Where's the problem? Do you think I'm going to have to get a new motherboard/I mean use it as an ashtray and get a new phone?

 

[gordonfink]

Sounds like maybe you disconnected the display cable. They sometimes look like they are snapped down, but aren't. I'd unsnap that and snap it back to make sure it's seated well.

One other possibility is a damaged component on the board. To verify that, you will need to look carefully at all of the little soldered doohickeys (technical electronics term), to see if any of them are twisted, broken on one end, or missing.

If it's item one, you're fine. If it's item two, you're hosed.

You can post a pic of the motherboard if you like and we can see if there's anything visible.

I have ruined a couple of motherboards by tearing a component on the board.

 

[omerfbingol]

I checked every flex cable, connectors, pins, etc. Everything seems okay. I might have short-circuited some stuff between the display pins and the cpu, while trying to remove its metal cover, maybe metal cover came in contact with something and burned them because of short-circuit. If that's not the case, I believe that was a trick by Nokia considering its warrant been over just a month ago. I experienced the same thing with my ASUS laptop, a little while after its warranty ended, the motherboard got bricked after a BIOS flash.
Anyways, I just sent it over to a repair shop waiting for a call about the problem. Thank you for the tips!

 

[djslofstra]

Well, I think you killed the PCB with static electricity or by short circuiting it. I think I had the same problem with a Lumia 820. The glass was broken but the screen still worked. After replacing the glass, the screen didn't work any more.

 

[omerfbingol]

I'm not sure I killed the PCB, considering that I can see device via USB and flash it and all.. Maybe I just killed it partially or I just burned my display...