How do I check my screen lighting. It is at half strength and the F4 and F5 buttons dont work?

You must have one of the newer OS versions (MP 2.53 and higher). You don't have anything under F5.

In Run screen, press OPTN>F6>F5 (Angl). The Degree/Minute/Second key is the TAB above the F4 Key.
To use the key for example to type in 58 deg 33 minutes, 27 seconds type in 58, press F4, type in 33, press F4, type in 27 then F4. Press EXE. The screen displays 58.5575.
A new tab appears above F5. Press it to convert displayed result to DMS

In Run>Mat press the OPTN key, Then F6:> to move to the next page of options. You will see the ANGL tab as on the screen capture (above F5 key.


Press F5. You will see what follows.


Type in 50, press the F4 key, 25 then F4, 23 then F4. Press EXE. you get the result in decimal degrees as on the screen capture. To convert from DMS to D.D, or from D.D to DMS, vice-versa, press the F5 key

Geoff,
You can Try fn+f4 again or try others eg f3 or f5.

hope it works.

You will need to press the FN key and F4 or F5 to make adjustments.

Maybe you have to press and hold the FN function key at the lower left side of the keyboard, then hit F4 or F5. Most times just pressing F4 or F5 will not work.

First of all check its warranty, if exists, concern the authorized dealer or representative. If not unscrew your calculator and clean keypad with a wet white cotton cloth by rubbing gently you will see black spots on the cloth. place the keypad at where it was placed previously. You will find it working as usual. INSHALLAH.

try the brightness buttons on the keypad on my dell i have to hold a fn button on the bottom and then f4 is brightness down and f5 is up my fathers has its on buttons sorry if you hve already checked the obvious if its not that then its the lcd backlight most laptop screens are different so you might be able to relace just the light pad but you may have to replace whole screen if you google it there are quite a few guides or you tube you can watch them dissasemble one as you do yours if you have any important stuff you need asap you can connect a normal monitor to the back of your laptop and use it untill you get relacement screen dont pay no more than about 70 fitting it your self is so easy

If you can still hear everything else working try adjusting the brightness, there should be keys to do this on the keyboard, if it has no effect i suspect your lcd back light has gone.

Model?
On My Travel mate screen resume after lid closed if I touch any arrow key
or If I use FN + ESC (Zee key)
On other model you can have to use FN F4 or F5 or F6
Check documentation at Acer WEb site