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1Back to top Go down   Gear Shift Indicator LCD Screen Empty Gear Shift Indicator LCD Screen Sat Nov 12, 2022 6:14 pm

gravelsandwich

gravelsandwich
active member
active member
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

    

2Back to top Go down   Gear Shift Indicator LCD Screen Empty Re: Gear Shift Indicator LCD Screen Thu Nov 17, 2022 3:08 pm

gravelsandwich

gravelsandwich
active member
active member
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.

    

3Back to top Go down   Gear Shift Indicator LCD Screen Empty Re: Gear Shift Indicator LCD Screen Fri Nov 18, 2022 2:38 am

charlie99

charlie99
VIP
VIP
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 ?


__________________________________________________
cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%OGear Shift Indicator LCD Screen Au-log10

'86 k100 rs.. #######..  "Fred " (f(rame) red ) ( Fredrick leichtundschnell ) - -
bits and pieces from many kind friends across the k100 world ...with many thanks ..
    

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