If it was plug and play then fine, I could do it. But he has to create a work around I think for a couple of the pins, or lack there of (I don't remember). He already knows of a couple solutions. My biggest concern is losing contrast control. I'll only be out like $30 plus labor if it doesn't work out. Not a big deal.
I9;ll let you know what happens soon.
On Wed, Aug 25, 2010 at 4:08 PM, Jack Pratt <woodsworth1@...> wrote:
Swapping LEDs is probably not going to work. Different LED colours have different forward voltage drops and blue LEDs tend to require a larger forward voltage drop than most. A typical LED has a forward voltage drop of around 1.2 - 1.8 volts, whereas blue LEDs often have forward voltage drops of 2.5 to 3.1 volts. If you merely replace the LEDs you probably won't get enough current to get any useful backlighting. Also blue LEDs often require a higher current to generate the same luminosity as other LEDs.
Probably [I haven't checked] the backlight input requires 5Volt (or possibly 3.3Volts) and in that case there will be a current limiting resistor which will be too large a value. You would need to find and replace the resistor(s) with smaller value ones. Alternatively, some LCDs just provide access to the anode and cathode of the LEDs for backlighting and you need to provide some surrent limiting of your own. In this case you will need to find that circuit (perhaps only a resistor) and modify it appropriately.
From: Atom Smasher <atom@...>
To: xl7@yahoogroups.com
Sent: Wed, August 25, 2010 10:00:30 PM
Subject: Re: [xl7] modding LCD ?
On Mon, 23 Aug 2010, James Ulibarri wrote:
> I want a BLUE unit to go with my PX-7. But it's impossible to find a
> unit that is 14 pin. I talked to Chrsystal Fontz today and their tech
> said you probably could use this one, At this point this won't work.
==================
i've done a fair bit of backlight modding, and if it was me, i'd try to
find a "drop in" replacement of any color, then just swap the LED(s). but
i'd do it on the spare, or at least have a spare on standby.
personally, i find green LED backlit LCD much easier on the eye's than
blue LED. the K5000 is a nice blue, but that's EL, not LED.
--
...atom
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