This seems like a good time to publish the EEPROM information regarding the 8757 family.? This includes all models although some only applies to the C/D/E models.? The chart does not mention the D model since that was introduced after this was written, but it still mostly applies.
To upgrade a monochrome display (E model) to a color display, two things must be done.? As mentioned, A14J2 pin 5 must be grounded.? Also, the value of Hex address 0C08DC must be set to any value such that Bit 0 = 0; generally, this mean any even number.? If Bit 0 = 1, then this tells the firmware that this is a monochrome display.? The values can be changed using the built in Hex Read/Write function described in the service manual.
Below are other values that may be useful; not all were ever used. Most were useful only to service personnel.
CV
? EEPROM DATA FOR OVERALL 8757C/E? ****? REV. 9/9/88? ****
????????? HEX
? #? |? ADDRESS? |????????????????? DATA
?----|-----------|--------------------------------------------------------------
? 0? |? 0C08C0 * | Free address for checking write protect? (normally 0000)
? 1? |? 0C08C2?? |??? UNDEFINED
? 2? |? 0C08C4?? |??? UNDEFINED
? 3? |? 0C08C6 * | Bit pattern?? data = HEX? A5A5
? 4? |? 0C08C8 * | Bit pattern?? data = HEX? 5A5A
? 5? |? 0C08CA * | 8757A/C/E Serial number validity code???? HEX? B38F
? 6? |? 0C08CC * | 8757C/E serial number suffix minus 32768
? 7? |? 0C08CE?? | 8757C/E serial number prefix minus 32768
? 8? |? 0C08D0?? |??? UNDEFINED
? 9? |? 0C08D2?? | Color monitor serial number? MSB
?10? |? 0C08D4?? | Color monitor serial number? LSB
?11? |? 0C08D6?? | Monitor installation date code YYMM
?12? |? 0C08D8?? | Original model number;? ASCII "C" or "E"
?13? |? 0C08DA?? | 8757C/E validity code????? HEX 4C70
?14? |? 0C08DC?? | Color Enable Flag (random #);? Bit0:? 0= color; 1= monochrome
?15? |? 0C08DE?? |??? UNDEFINED
???????????????????????????????????????????????????????????? * = Same as 8757A
?-----------------------------------------------------------------------
?------------------? ****? ADC INFO? ***? --------------
???????? HEX
? #? |? ADDRESS? |?????? CONTENTS
?----|-----------|-------------------------------------------------------
???? |?????????? |
? 0? |? 0C08E0?? | ****? UNDEFINED? ****
? .? |?????????? |?????????? .
? .? |?????????? |?????????? .
? .? |?????????? |?????????? .
?31? |? 0C091E?? | Checksum +1 for all the above addresses from 0C08C0
?-------------------------------------------------------------------------
?NOTE:? The checksum contained at address 0C091E is used for both the
??????? ADC block AND the OVERALL 8757 block; a total of 48 words.
??????? UNDEFINED locations should have hex data of? 0000.
------------?? ?? MONITOR PRESETS?? ? -----------------
???????? HEX
?? # |? ADDRESS? |????? CONTENTS
?----|-----------|-----------------------------------------------------------
?? 0 |? 0C0920?? |? Intensity DAC; 100 Nit? Data = 5AXX? where XX = DAC value
?? 1 |? 0C0922?? |? Intensity DAC;? 20 Nit? Data = 5AXX? where XX = DAC value
?? 2 |? 0C0924?? |? Backround DAC; nominal? Data = 5AXX? where XX = DAC value
?? 3 |? 0C0926?? |???? UNDEFINED
?? . |??? .????? |???????? .
?? 7 |? 0C092E?? |???? UNDEFINED
?----------------------------------- END --------------------------------------
