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7D01/Repairs: Difference between revisions
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However, there are pin headers P207, P208, P209 and P210 next to the CPU, originally used to connect the memory daughterboard or a test system, that make it easy to add a small custom piggyback board with a decoder and a more modern E(E)PROM. An 8k×8 chip (2764, 2864) is sufficient to hold the 6kB needed for the DF2. As a bonus, this upgrades a DF1 to a DF2 if the missing front panel key is added as well (pads are present on the PCB). The stock ROM chips are removed. | However, there are pin headers P207, P208, P209 and P210 next to the CPU, originally used to connect the memory daughterboard or a test system, that make it easy to add a small custom piggyback board with a decoder and a more modern E(E)PROM. An 8k×8 chip (2764, 2864) is sufficient to hold the 6kB needed for the DF2. As a bonus, this upgrades a DF1 to a DF2 if the missing front panel key is added as well (pads are present on the PCB). The stock ROM chips are removed. | ||
<gallery> | |||
Tek DF1 DF2 ROM replacement board schematic.png | ROM piggyback board schematic (click to enlarge) | |||
</gallery> | |||
''Board files will be added after verification'' | |||
[[Category:Instrument repair reports]] | [[Category:Instrument repair reports]] | ||