Have you measured the -5V supply to see what voltage it actually is? A low -5V (closer to 0V) will make for a dim display.
Jeff Birt -----Original Message----- From: M100 <[email protected]> On Behalf Of Scott Lawrence Sent: Friday, December 24, 2021 6:50 PM To: Model 100 Discussion <[email protected]> Subject: [M100] Tandy 200 lcd The lcd on my 200 has horrible contrast. I’d use the thing more but I just can’t read the screen. Have any of you done any mods/repairs for this? Would the “bivert mod” common for gameboy DMGs work? (Electronically invert the screen, and replace the polarizer with a modern one rotated 90) Are there maybe power supply repairs that would help? Thoughts? Sent from your iPhone.
