06-10-2022, 10:17 AM
The Thick brown wires look to be repairs for the keyboard matrix.
Some of the blue wires (at the Font Rom) are mods to take the 4732 dual font rom.
The black wires near IC33,34 are most likely the mods to allow the baseboard to work with the DRAM coreboard (CIAB upgrade).
The Blue wire near IC30,32 is most likely due to the 12Mhz -> 13.5Mhz clock upgrade (Cpu 2Mhz -> 3.375Mhz)
The baseboard looks to have been part of a kit bee from the soldering, although from the component side it looks like a factory build.
As to the miscellaneous resistor changes, other links, perhaps look at the hardware notebook in regards to upgrades to the cassette interface, serial port, parallel port
and video output circuitry.
Some of the blue wires (at the Font Rom) are mods to take the 4732 dual font rom.
The black wires near IC33,34 are most likely the mods to allow the baseboard to work with the DRAM coreboard (CIAB upgrade).
The Blue wire near IC30,32 is most likely due to the 12Mhz -> 13.5Mhz clock upgrade (Cpu 2Mhz -> 3.375Mhz)
The baseboard looks to have been part of a kit bee from the soldering, although from the component side it looks like a factory build.
As to the miscellaneous resistor changes, other links, perhaps look at the hardware notebook in regards to upgrades to the cassette interface, serial port, parallel port
and video output circuitry.