[sdiy] Why do LCDs die?

[Roman Sowa]

It may be that driving signals were not precise enough. Bad 
non-symetrical levels and bad timing might have caused DC component to 
appear over glass. Mean value of the voltage actross any part of crystal 
must be 0V, otherwise it will be damaged over time.

Roman

W dniu 2018-12-31 o 03:53, Tim Parkhurst pisze:
> So, I have an old Roland U-220 that I haven't used in a few years, but I 
> keep it around because I do love the piano and string samples. The 
> fretless bass and the drums are pretty good too. Also, I'd be lucky to 
> get $50 for it these days. Long story short, I turned it on the other 
> day and the LCD was barely visible, getting dimmer to the point after a 
> few hours where it is completely unreadable. The backlight is okay, but 
> the digits themselves can't be seen. I see there are replacements on the 
> market, so I should be able to resurrect it, but this begs my original 
> point:
> 
> What causes LCDs to die in the first place? Are the crystals themselves 
> unstable? Is it the high-frequency excitation required that causes an 
> eventual breakdown? Or is it mechanical, with small connections or wire 
> bonds breaking down with time? Do we replace them because they are 
> unrepairable, or is it simply a matter of replacement being quicker and 
> cheaper than repair? Is there an internal adjustment to crank up the 
> contrast on this old beast (can't change the contrast from the front 
> panel settings since I can't see the display to navigate)?
> 
> Awaiting the collective enlightenment from the SDIY hive mind...
> 
> Tim (do Borgs get hive mind hives?) Servo
> 
> 
> 
> 
> 
> 
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