Hello everyone, as the title mentioned i own a Casio Fx Cg-20 which i use in my classes and it's backlight is not working. The screen itself is working as i can see it working with enough ambient light. The brightness setting is obviously useless here. Batteries are fresh too. Does anyone have experience with these things or can maybe identify the problem just by looking at the board? I should add that the backlight works occasionally, for example, it worked for like 15min. after i put fresh batteries and it also sometimes worked when i took out the old batteries and put them again. The calculator also showed 2/3 battery before i replaced them so battery problem is out of the way i think. Thanks in advance.

 

Holy hell i think i've just solved it... I think this is my luck of the year. I'm sorry if i wasted anyone's time but i will still leave this here for anyone with the same problem in the future.

So, in my understanding that big connector uptop is what connects to the screen itself, and that little 2 pin connector is what powers the backlight as far as i know. Mine was a little raised and i thought it was normal, i tried pushing it down anyway by hand and put it back together and still didn't work. There's no way to test things since the batteries have to be off to access the back btw. So what i did was to put a little piece of toilet paper stuck on the back piece (check attached files) and it's working. I took the batteries out and put them back in a couple of times, restarted it and it's still working.

 

Is this the month of broken CG20s? My son's CG20's display light is also broken I learned today and your fix doesn't seem to help here

 

Correction: I gave it a second try using toilet paper instead of normal paper. IT WORKED.

Thanks for your tip.

Nevertheles, I'll try and get it repaired after his maths exam.

 

Glad I could help

 

Holy hell i think i've just solved it... I think this is my luck of the year. I'm sorry if i wasted anyone's time but i will still leave this here for anyone with the same problem in the future.

So, in my understanding that big connector uptop is what connects to the screen itself, and that little 2 pin connector is what powers the backlight as far as i know. Mine was a little raised and i thought it was normal, i tried pushing it down anyway by hand and put it back together and still didn't work. There's no way to test things since the batteries have to be off to access the back btw. So what i did was to put a little piece of toilet paper stuck on the back piece (check attached files) and it's working. I took the batteries out and put them back in a couple of times, restarted it and it's still working.

It really works thx man

 

Had the same issue and your fix worked perfectly. Thank you so much!

 

Hello everyone, as the title mentioned i own a Casio Fx Cg-20 which i use in my classes and it's backlight is not working. The screen itself is working as i can see it working with enough ambient light. The brightness setting is obviously useless here. Batteries are fresh too. Does anyone have experience with these things or can maybe identify the problem just by looking at the board? I should add that the backlight works occasionally, for example, it worked for like 15min. after i put fresh batteries and it also sometimes worked when i took out the old batteries and put them again. The calculator also showed 2/3 battery before i replaced them so battery problem is out of the way i think. Thanks in advance.View attachment 222411View attachment 222412View attachment 222413

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Holy hell i think i've just solved it... I think this is my luck of the year. I'm sorry if i wasted anyone's time but i will still leave this here for anyone with the same problem in the future.

So, in my understanding that big connector uptop is what connects to the screen itself, and that little 2 pin connector is what powers the backlight as far as i know. Mine was a little raised and i thought it was normal, i tried pushing it down anyway by hand and put it back together and still didn't work. There's no way to test things since the batteries have to be off to access the back btw. So what i did was to put a little piece of toilet paper stuck on the back piece (check attached files) and it's working. I took the batteries out and put them back in a couple of times, restarted it and it's still working.

Idk if you're gonna watch this or not but thank you. That hack just saved 80€, the toilet paper works wonderfuly well

 

Here is a solution to the issue. If you have a soldering iron available set the temp to 380. De-solder the backlight ribbon cable by placing the soldering iron tip across the 2 two connection points of the cable. Add additional solder to the display board you just de soldered the backlight ribbon cable from. Use tweezers to push down backlight ribbon cable onto the display board. With your soldering iron contact one of the top two connections of the display ribbon cable with the soldering iron until the solder underneath melts and ribbon cable sits flush with the board. Repeat. Repeat this step for the additional connection.