CQ50z-100 - black screen after taken apart for cleaning

Took apart my old CQ50z-100 to clean the fan, put it all back together, and the screen didn't turn on. It was working fine before I took it apart, but I honestly have no idea what went wrong.

Currently, I have it plugged in with damn near everything removed (keyboard, touch pad, battery, optical drive, WiFi card, RAM, HDD) and only have the "Power/WiFi" button attached via ribbon cable. Everything lights up and the fan spins, but the screen stays black.

1) Shouldn't I be getting some sort of audio response with no HDD or RAM installed?

2) I'm assuming this is another case of bad screen-to-motherboard cable, but it was working perfectly before and everything was put back exactly the way it was

The screen has 4 cables: two little pop-on connecters to the WiFi card, one cable that looks like this (probably the LCD cable), and a smaller version that I believe is the mic.

Hopefully me cleaning out the laptop wasn't all it took for this thing to go kaput -___- Thanks in advance, all.

 

You need RAM in order for the machine to POST. So put that back in.

A lack of display signal doesn't necessarily indicate the LCD or LVDS cables, the system may not be getting far enough to POST due to any number of hardware issues like a short somewhere or a dislodged CPU or badly seated RAM, etc.

 

Could have sworn there were supposed to be audio warnings for undetected RAM/hard drives so you could theoretically "build up" to the problem.

With what I've seen online regarding this line of Compaq laptops and troubleshooting (mainly screen related) I think my safest bet would be to buy a cheap VGA cable and use my desktop monitor to check if the laptop screen or cables were the issue. If one or the other is the case then I'm not sure how to proceed. Will post back with more.

Thanks for the help, AL.

 

Sometimes there are beep codes, sometimes you'll get flashing LEDs, sometimes nothing. It depends on the system. Your best starting place is to check all of your connections over and make sure all the components are seated properly.

 

Done that multiple times already, hence suggesting the VGA cable. Guess another couldn't hurt...

 

Really hard to tell what happened out there. I am too cautious with my laptop and end of tenancy cleaning gold coast it is a big headache for me.

 

Oh, there's no doubt cleaning out laptops is a pain in the backside (haven't come across an easy-access one yet), but you can't beat the increased airflow and while I'm in there I'll reapply the thermal paste to the CPU, anyway. Lowers the overall temperature by a handful of degrees.