Sharp MZ-2000 Upgrades
Amongst the machines I am currently renovating is a Sharp MZ-2000, the successor to the venerable Sharp MZ-80B. This machine not only provides the ability to run MZ-80B software but adds 48K VRAM for full colour output and all encapsulated in a very aesthetic design based on the Sharp MZ-80A casing.
Like most machines from Japan which werent intended for export, the power supply runs at 100V (it will operate at 110-120 so countries such as the USA have no issue). As this machine uses a transformer rather than the more recent switch mode supplies, it is easier to adapt to run off 220-240V.
Testing on the transformer indicates the primary winding only has one coil and it is limited by design to input voltage. The input current rises exponentially as the voltage goes > 140VAC (tested using a VARIAC) so my new solution is to replace the original laminated core transformer with a toroid, the toroid has 2x22VAC@2Amp + 15-0-15VAC@1Amp outputs, 3 coils are required by the MZ-2000 PSU. The toroid will sit on a metal adapter and be held down by the original transformer screws so no damage to the machine is incurred.
Of the issues encountered so far during renovation, the cassette tape pinch roller has disintegrated, turning into a tar like paste so this will need sourcing and replacing.
I have tested the tranZPUter SW-700 board in the MZ-2000 and not only does it fit, the machine runs reliably. Using the tranZPUter SW-700 requires a few cable adapters and the video GRAM card cannot be installed but the tranZPUter board can fulfill all video and graphics functionality the video GRAM card provides yet add many more features.
One of the advantages in working with a real machine is knowledge gained. It is alright working from books and schematics but interacting with real hardware, at least from my point of view, offers a great deal more insight and you have a benchmark to compare an emulation against.
I have held off from finishing the MZ-2000 emulation in the Sharp MZ Series for a few reasons but now I have no excuse. Adapting the tranZPUter SW-700 v1.3 board I can upgrade the Video Module to match the VRAM card and have both to hand for comparison. Any changes I make to the CPLD/FPGA to make it operate in the MZ-2000 will no doubt feed back into the emulation.
The Sharp MZ-2000 prior to renovation, this is my new machine, it doesnt need so much work as it is a very clean example, just the electronics, monitor and tape deck need servicing and calibrating.
Work In Progress! Watch this space!
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