Hi Everyone,
I embarked on replacing my gear shift indicator LCD, it works but the display is extremely faint. Rather than go to LED I prefer to keep the LCD screen and soon discovered the availability of a single digit seven segment display in the right proportions is non existent, however I did find some screens in 3 and 4 digit display with the correct digit size that are cheap and readily available.
I bought a 3 digit display and printed a mount to fit onto the board and into the cluster so only the center digit shows through the window. 
I wired it to the board but I can only get a zero to appear. Shifting through the gears it disappears in gear 4 and 5 and comes back on shifting down to 1st. There seems to be 5v at the board and drops slightly I assume when the segment is supposed to not display, I tried adding resistors to lower the voltage to about 3v(LCD operating range) but no luck and this is where my electronics ability have ended!
If somebody can add to this or maybe suggest something that would be great. 
http://forum.kforum-tech.com/members-upload/uploads/20221113_072640.pdf


http://forum.kforum-tech.com/members-upload/uploads/20221113_072738.pdf

With a bit of perseverance I've got it working at least partially. Its definitely a voltage issue, I used a mini buck converter between the board and the LCD screen and the segments connected work as their supposed to. I'll keep playing with resistors for now but at least buck converters although a bit bulky, I need 6, will work. 
 The printed mount is available on Thingiverse. Ill post more detail when I complete the project.

the driver chip that operates the lcd has an onboard oscillator that generates the voltage and frequency  required for the lcd to operate , if perhaps the lcd display circuits were loaded with corrosion - leakage (extreemly hard to see with the naked eye ) it may have affected the output of the chip , also dont forget that the electrolytic capacitor closest to the chip could have leaked or dried out , now not letting the oscillator work to its full potential or just corroded power supply pins from the film circuit to the gear indicator board 

i have an indicator on my new to me RED  bike that is verry faint also 

it will have to wait a while , whilst i sort out other running drivetrain issues before i go inside there to sort out a few issues , like led used for charge indicator for alternator and a flakey odometer zero wind assembly not connecting to all gears , plus the lcd display ....perhaps one day soon ?

Ok, after much fiddling about I've finally got the new gear LCD screen to work so it is possible. Turns out I didn't need resistors at all, just connect straight to the board (thanks Charlie!). 
I drilled .8mm holes through the board pads and soldered 2x4 90deg JST female pin headers directly to the board to keep the wires contained. Because of the angle I had to print a new board support piece to clear the JST pin headers. The printed LCD screen mound and the support piece are both on "Thingiverse" for anyone to download if you have access to a 3D printer. The screen came from AliExpress listed under "24pin 3 digit LCD" and cost about $6 delivered. It's non backlit.

JST 90deg pin headers. I would have preferred mini JST headers but these line up with the board pads.


Wires to the screen are hot glued in place. A little less glue would have been better as there isn't much clearance between the screen and the board.


Just enough clearance for the wires and glue. You can see the support piece angled down to clear the JST headers. You could use straight headers but I was worried It might interfere with the Tacho.





and here's the result.

Nice job!

well done, gravelsandwich

thanks for sharing and the detailed documentation

great result , well done

That's great, thanks. I want to do mine now

Very cool.