Bram Jacobse

Tinkering CD Players & Digital Audio

CD 100 Servo and Sub-Code CPU ROM backups

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Some time ago i had a development F 8421 Compact Disc Player Handmodel nr. 85 on my workbench , The player had two development MAB processors and ROMS chips , i made a backup copy’s of these ROM’s

The MAB8400 Piggy back processor  with  E252 Firmware for the Servo.

The  MAB8400 Piggy back Processor with E536 Firmware for Subcode

After some searching I found new and working MAB8400 piggyback processors ,I did not have the right eproms , after some  workarounds ,  i could test the Rom copy’s

Testing in a CD100/30 Piggyback Servo and Subcode Processors with ROM copy’s

a backup is a backup if you could restore it: Testing Copy roms in CD 100/30

 

In production CD 100 the Servo Processor can have the following firmware versions

Movie showing difference in TOC reading and  acces speed , on the left CD 100 with D011 vs on the right CD 100 with  D023 firmware : CD100 D011 versus D023

In production CD 100 the subcode Processor  can have different firmware versions

  • B002
  • B007 this version has Absolute and Track time, used in de CD 202 and CD 303 and Late CD100/30

 

I also recieved photo’s of F 8421 Compact Disc Player Handmodel nr. 394