Illuminating the HP49G LCD display?

[Vtile]

(01-07-2022 07:16 AM)n3mmr Wrote:  I tested my 49G the other day, and it had developed keyboarditis, i e to start it up you have to push hard on the bezel above the softkeys in order for it to wake up.

So: I'll have to open it up and fix the kbd connector.

So I thought I might try to add some LEDs arranged near the display to improve readability of the rather dim LCD.

Has anybody else tried this?
What LEDs could you use? Where should you connect the LED to minimize the strain on the electronics and so it would only light up when the calculator is on?

I suppose you have opened it already, anyway if the internals are similar than in 50g there is no much room for leds. Only point where the leds could work is an edge of the LCD glass edge, but the illumination effect is rather poor and in 50g only SMD devices fit physically IIRC. SD card and IIRC serial port did have place to make software controller FET switch for leds. One option would be removing the entire back coating of LCD and replacing it with something illumination friendly diffusor, but I never did go that far on re-engineering.