[sdiy] Why do LCDs die?

[Tony Kalomiris]

>From the MRC service manual:

"A DC to AC converter, T101, converts +5VDC to approximately 100 VAC which
supplies power to the fluorescent lighting on the LCD display via J110 and
is self-adjusting as the LCD ages."

That last part surprised me, self-adjusting backlight? It's not shown on
the schematic but that 14 pin connector, J110, looks familiar (Hitachi
44780).
I don't see how the chip select, CS6, from that NAND gate, could make a
difference in brightness, but hey if you say so, who am I to question why.

Tony

On 18-12-30 11:17 PM, "MTG" <grant at musictechnologiesgroup.com> wrote:

>Anyway the MRC .. U118 is a 74HCTLS on the ones
>I fixed. I had to replace it with a 74LS00. Then it was fine. Don't ask
>me how I came to that conclusion but maybe with a schematic in front of
>me I could say better.