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Like a few of my other projects, this one started with an old Apple II motherboard that I had in my box of electronics stuff. This too did not have any surviving external peripherals so in order to revive it I had to rebuild a everything including power supply, keyboard, speaker, and ROM card (this is a GTAC-2 clone).
This is the motherboard. It is a clone that has a Z80 CPU on-board and does not require an expansion Z80 card like the Apple II does. This setup takes away expansion slots 0 and 4. The ROM is connected via an external expansion card in a special slot names ROM used to run a clone Apple II ROM, but since this clone is almost an exact copy of the Apple II it can take the original Apple ROMs as well.
Several references exist on the web for this machine:
Here's what I did to rescue this motherboard and bring it back to life
Reconfigured an ATX power supply with a plug adapter and a 5.1v Zener diode to provide a -5v rail (needed by the tape input LM741 op-amp)
Rewired an small 8ohm speaker
Built an expansion card for the ROMs. I consolidated all ROMs into one EEPROM on a normal expansion slot instead of using the dedicated ROM slot. This required adding some address decoding, but otherwise provides a compact setup with plenty of opportunity for adding other expansions on the same large card.
Built a PS2 keyboard to Apple II parallel translator, see GitHub repository https://github.com/eyalabraham/apple2 for details
I had reverse the 50Hz video modification, hook up a composite monitor and load games found on-line through the tape input from an iPad audio output.
Partial setup
Signs of life, color video scan-lines
With Apple II ROMs
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