We have a fire monitoring/management panel which has a 40x4 character display attached to provide information in the event of a fire.

It has recently started "glitching out", it displays random characters/glyphs for split-seconds in random places on the display. These are valid alphanumeric characters (not just random pixels etc), which leads me to think the LCD controller is damaged, which happens to be on-board the display PCB.

We have had a quote provided to replace the panel, but we'd much rather replace just the character display (huge difference in price).

I'd like to make sure however, that the display is the part malfunctioning.

What are your thoughts?

This is a very similar character display I found an image of online.
This is a very similar display for reference.

  • \$\begingroup\$ Order the display, replace, check that it still doesn't work, order the panel. Or just order the panel from the start. A miser pays twice they say. \$\endgroup\$ – Dmitry Grigoryev Jun 27 '17 at 16:52

I suggest you let the manufacturer of the fire alarm work on it to keep it in warranty.

The LCD can be easily tested with an Arduino, if you know the pinout.

Problem is, that the issue might be caused by the LCD, the power supply, the main processor or a combination of those. Replacing the LCD and seeing if the issue remains is less work. Those LCD's go for ~$20.

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