Black screen after DC board replacement and quick fan clean

[PeroxcideFlowers]

ASUS N53SV - nearly 5 years old

DC port carked it a few months back and I've sort of left it for a while as I needed a new battery and AC adapter as well (originally thought the adapter was the issue so I spliced it). The screen has always worked fine with no issues prior to the day the DC port gave out and the old battery drained.

I opened up my laptop this morning, replaced the DC board and removed the whole motherboard (with the fan still attached) to clean out all the dust. Ran compressed air through the fan while holding the blades still so the fan won't become unbalanced. Put everything back in the right order, aside from the RAM as I couldn't remember which was originally in what slot (I have 4 bits of 4GB RAM).

Finally chucked in the new battery and adapter but now the screen won't come on. All the lights come on, fan works fine, CD drive makes the usual start-up noise. The screen just looks like the laptop was never on in the first place - no backlight or anything.

What would something just suddenly stop working?
Have I missed something?
Could it have something to do with the RAM boards being in the wrong spots?
Could it be because I downgraded the battery from 10.8v 5200mAh/52mAh to 10.8v 4400mAh/48Wh?
Is there anything I can do short of taking it to a repairman?

 

[Laptop_Nerd]

Hi,

Do identify if it's a problem with the display or there might just be a loose connection some where.
- Connect and external monitor while the laptop is on and see if you'll get any display from it because if you that means it may just be a loose connection between the LCD and the motherboard.
- If these will not work do reseat the RAM's, remove them all for couple of seconds then put them back in making sure that they are all seated properly. It actually doesn't matter where they go as long as they are all the same.
- If all these will not work it maybe the motherboard itself that has the problem.

 

[PeroxcideFlowers]

Thank you for your advice! I tried your first step but the external screen wasn't picking up a signal so I checked the RAM. Turns out I hadn't inserted the top two boards properly. I also checked the VGA cable to see if that was properly connected, which it was. However, when those didn't solve the problem either, I tried a step that was suggested in another forum:
- Removed the HDD
- Turned on the laptop with just the AC adapter supplying power to it (no battery). The screen came on and asked me to insert the boot disk/HDD
- Inserted the HDD and started it up in safe mode. It froze while trying to load the system files so I played the risk card and forced shut down via the power button.
- Inserted the old battery and restarted with all components in place.
- Asked if I wanted to do a disk check but I skipped that step because I was too excited and impatient. I would, however, recommend doing that, purely because there's probably a file somewhere in some folder that's been corrupted somehow and I'll come across it one day.

I can gladly say that the HDD step worked! I've checked to see whether anything on the HDD is corrupted or missing and everything seems to be in place so far. I'm so damn happy that it wasn't an issue with the motherboard though, as I'm not keen on paying $150+ to get it fixed by the repair guy.

Again thank you for your help!!

Hi,

Do identify if it's a problem with the display or there might just be a loose connection some where.
- Connect and external monitor while the laptop is on and see if you'll get any display from it because if you that means it may just be a loose connection between the LCD and the motherboard.
- If these will not work do reseat the RAM's, remove them all for couple of seconds then put them back in making sure that they are all seated properly. It actually doesn't matter where they go as long as they are all the same.
- If all these will not work it maybe the motherboard itself that has the problem.