LK204-25 Display clears text and seems to reset w/keypad use


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LK204-25 Display clears text and seems to reset w/keypad use

Post by jason »


I've got a couple of devices that are controlled by micros that have the LK204-25 displays attached to them. When I'm running the equipment (A lot of RF in the area) and I have the keypad plugged into the display, the display loses it's text and the backlight flickers on and off. If I unplug the keypad, the display works fine. (Note: When I have the device turned on, everything works, it stops working when I'm actually running/driving the equipment) I've tried emi sheilding on both sides of the keypad but that didn't do anything for me.

Any thoughts or suggestions? I've tried other displays and other keypads and they do the same thing.


Matrix Orbital
Matrix Orbital
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Location: Calgary

Post by Tom »


What you can try is if your keypad has a grounding plane, connect it to a ground location on the LK204-25. Have you also enclosed the display, so it is shielded from noise? You may also want to try placing 470 ohm resistors inbetween the keypad and the keypad connector. The lines to the keypad go straight to the pic, so you can experience some interference from the direct connection.

Try these suggestions, and let me know how it works out for you.

Best Regards,

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