From: legg@nospam.magma.ca   
      
   On Sun, 24 Dec 2023 09:45:39 -0800 (PST), three_jeeps   
    wrote:   
      
   >On Sunday, December 24, 2023 at 11:22:45?AM UTC-5, legg wrote:   
   >   
   >> I've seen LCDs that have obvious damage/discoloration   
   >> and flakey elements before, but never something that   
   >> was permanently, uniformly dark.   
   >>   
   >> There's no carbon press strip to degrade, just 15   
   >> solderable in-line pins.   
   >>   
   >> I would suspect the controller chip, or its ceramic   
   >> resonator, but the chip seems to be performing normally.   
   >> The unit runs.   
   >>   
   >   
   >"All necessary wiggles being delivered to solderable pins" -   
   > Not sure what this means so I'll make an inference:   
   > All the LCD segment lines change state appropriately?   
   > Checked voltages on all segment pins at the same time   
   > (with perhaps a 16 line digital analyzer)?   
   dream on   
   > Bias voltage on the LCD correct? If all true then the LCD is dead.   
   >Does this model have a separate LCD controller chip or does it use a micro   
   with a number of DIO lines?   
      
   Service manual shows 4x9 connections more suited to an LED display   
   coming from a 64pin micro through a quad buffer and nine unbuffered   
   lines from paralleled ports with 100R series limiters.   
      
   The current rev board is a 56pin QFN package driving the 15 pins of   
   the display directly.   
      
   3 of the 15 pins generate quad-state ~ramps between 0 and 5V.   
   Pins 1 , 2 and 10.   
   The rest just clock (150Hz) between the two mid-state levels, in   
   sync with the ~ramping steps.   
      
   This controls segments of 4 digit clock, its middle colon and   
   5 symbols for mode of operation, spaced ~ equally below the digits   
   and mid-colon.   
      
   I've searched all over for a more accurate service manual, or   
   a revision that includes the change to micro and display, but   
   this is only reflected in purchasing spares. The old control   
   panel assy number is retired to be replaced by . . .   
      
   A custom LCD-only part for the control board assembly isn't a   
   likely after-market item. The whole panel is available for $$$.   
      
   This one is from 2012, about half way through the product's history.   
      
   RL   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)