16x2 Character LCD - Dead Segments

Does anyone have experience with character LCD segments becoming stuck to solid black?

The LCD in question, I believe, is contains a S6A0069 controller. This seems to be a replacement for the HD44780.

Upon simply powering the display, the 8 right hand segments are completely blacked out at all contrast levels. Running the LiquidCrystal Hello World example allows for the top line to display the first 8 segments of "hello, world" with everything after the 'w' remaining as darkened out segments. The second line initializes the same as the top line, with the right 8 segments being darkened out too.

After reviewing the spec sheet and given that the counter in the Hello World example works fine in the bottom left hand side, it would seem that the memory addressing works fine, and rather the segment drivers for the right hand segments of the S6A0069 controller have become damaged.

Just wondering if this has ever happened to anyone else before. The LCD in question was purchased almost 7 years ago and seemed to work fine back then. The only thing I can think of is that I had to solder some wire to the connector of the D7 line and that potentially overheated some other components, but I recall this display working in spite of that.

If nothing physically traumatic has happened to the LCD unit, is it common for cheap segment LCDs to crap out over time?

I think those drivers actually drive 8 characters:

A single HD44780U can display up to one 8-character line or two 8-character lines.

Thus to get 16 they put two drivers on the board, and it sounds like one has failed. You could check for dry solder joints or something that might account for that.

If nothing physically traumatic has happened to the LCD unit, is it common for cheap segment LCDs to crap out over time?

I have been using the same LCD modules for more than 20 years, but they weren't cheap, they are name brand (Optrex) devices.

... it would seem that the memory addressing works fine, and rather the segment drivers for the right hand segments of the S6A0069 controller have become damaged.

Give the man a cigar.

The S6A0069 controller contains the main microprocessor and all of the memory needed for your module but it only controls characters on the left half of your display. Your LCD module also has an auxiliary controller (probably a S6A0065 or S6A20670) which may be covered by the same epoxy blob as the S6A0069 that controls the characters on the right half of your display.

So, it appears that this auxiliary controller is the culprit but it is most likely the connections between the pc board and the glass that are the problem. You could try applying pressure to the bezel that surrounds the glass and see if anything changes.

Don

If the pixels are black all the time, it's not a bad connection to the LCD glass. It's a problem with the connection between the two controller chips. The chips you have onyour display is not a replacement of the HD44780, it's a 1:1 clone.

// Per.