Casio-TV LED-backlight mod question.

Meff · Post by **Meff** » Fri Mar 16, 2007 1:30 am

HI!
I have just bought my Casio portable TV and it sucks power so much (4W on 6 AA's!) that I want to make a LED backlighting mod on it. And I have some questions. If I install 2 LEDs like Ben did here, will I still be able to change the brightness of the screen with the potentiometer? And is this mod worth it? Is it good for watching TV on this portable TV?

Thanks in advance,
Meff

Kurt_ · Post by **Kurt_** » Fri Mar 16, 2007 10:45 am

The LED mod will save you energy. But half an amp isn't a whole lot of power drain (roughly 4-5 hours battery life).
If you feel you must, do the LED mod. The backlight won't be adjustable, but you can easily add a potentiometer into the LED circuit to make it so.

Meff · Post by **Meff** » Fri Mar 16, 2007 11:19 am

Kurt_ wrote:The LED mod will save you energy. But half an amp isn't a whole lot of power drain (roughly 4-5 hours battery life).
If you feel you must, do the LED mod. The backlight won't be adjustable, but you can easily add a potentiometer into the LED circuit to make it so.

Okay, thanks. But did somebody use this mod on portable TV's to watch television? I have to know if it will be still possible to watch the television with the LED backlight.

vskid · Post by **vskid** » Fri Mar 16, 2007 11:21 am

The LED mod only affects how the screen is lit, it still has all of its original features.

jeroen · Post by **jeroen** » Fri Mar 16, 2007 11:21 am

It should be possible as long as you don't remove the tuner? what makes you think it won't work?

Meff · Post by **Meff** » Fri Mar 16, 2007 1:01 pm

Uhh, I didn't really say what's the problem. ^^'
I don't think it won't work. I just think that the LED backlight would 'destroy' the 'comfort' of watching television on the original backlight, but I don't really know, so I want to make sure by asking you guys.

And sorry if my english is bad. I'm from Poland.

G-force · Post by **G-force** » Fri Mar 16, 2007 2:45 pm

Just a note: if there is a a "brightness" adjuster on your LCD, a trim pot, or buttons, or whatever, that really is a contrast adjuster, it has nothing to do with the backlight itself. The screen's brightness/contrast adjuster will make the screen appear brighter/darker. The backlight, whether it's the original or not, will always stay the same brightness level. The only reason you would need to dim an LED backlight is if.... actually there is no reason, since LED's tend to be rather weak, and you want them as bright as you can get them (without overpowering them of course.)

So you're worried about the quality of backlight then? If you do it right, it's pretty nice. Not quite as good as the original will be, but not enough that you will wish you had not done it.

c_mon · Post by **c_mon** » Fri Mar 16, 2007 7:18 pm

Kurt_ wrote:The LED mod will save you energy. But half an amp isn't a whole lot of power drain (roughly 4-5 hours battery life).
If you feel you must, do the LED mod. The backlight won't be adjustable, but you can easily add a potentiometer into the LED circuit to make it so.

Did you mean replacing a potentiometer with the resistors or just adding it to the circuit? Also what kind of potentiometer shoud be used? Do you have any schematics or diagrams?

Kurt_ · Post by **Kurt_** » Sat Mar 17, 2007 9:42 am

Well, like G-force said, if your TV is adjustable now it will be after. In short, don't worry about it.

But if you must carry this out, this is how it's done:

Did you mean replacing a potentiometer with the resistors or just adding it to the circuit?

Just adding it into the circuit. If you remove the resistors, their purpose will be defeated, since a pot can go to 0 ohms, but the resistors have a set value to limit current flow.

Also what kind of potentiometer shoud be used?

Any that suits your needs. Almost any should work fine. Experiment a bit, have some fun, or get 10,000 ohms or more. More will decrease the sensitivity and less will increase it.

Do you have any schematics or diagrams?

No, but follow the original how-to, and add the pot in between the resistor(s) and the power source.

(And your english is very good. Don't worry so much about it)

Haku · Post by **Haku** » Sat Mar 17, 2007 5:47 pm

I got a Casio EV-660 today for the bargain price of Â£8.20, planning on making a portable with it but can't decide what system to go for (I have a dead Atari Lynx mk1 that might be suitable for the case), anyway I've seen the guide for the EV-680 and I had a peek inside this EV-660, powered it up with the front half of the shell off to see where the florescent tube actually was.

The guide puts 2 3mm LEDs into the ends where the florescent tube wires come out, but has anyone tried putting a string of say 4 LEDs inside for a brighter screen or does 2 provide enough light?

I've experimented with filing down 3mm LEDs to embed them in 8mm thick polycarbonate sheets to light them up as part of a sculpture, and also putting a row of 4 filed-down LEDs inside a 4mm clear tube so I'm confident it's possible to fit several 3mm LEDs in place of the florescent tube.

Meff · Post by **Meff** » Sun Mar 18, 2007 6:50 am

Thanks go to G-force and Kurt_. You guys helped me a lot! xP

Back to the topic - I opened up my Casio TV-6500 to look on the backlight. Well, what I've seen was just unbelievable. The backlight in TV-6500 isn't just a small 3mm in diameter light bulb. In 6500 there are two big (about 10mm in diameter) light bulbs! And that's why it sucks 4W of power! I think I'll have to make two 5mm neons (?) and place them where the original bulbs were.

And by the way. While I was closing the TV I did something wrong, and now it doesn't catch any channels on UHF so I think I'll make it just as a monitor for A/V without the ability to watch TV. xP