During the last year I've seen numerous messages from MSX users, whose computers stopped working after being removed from the storage or after another power cycle. Many people complained about black screens or about total power failure. It's a known fact that RAM and other elements may go bad during storage or at power-on. Diagnosing those problems usually starts from checking the power rails, clock signals, reset signal's state and activity on data and address bus. It has been decided to create a simple diagnostics cartridge that could help to perform the initial check of a computer and rule out the most common problems.
The cartridge named "iBolit" (https://en.wikipedia.org/wiki/Doctor_Aybolit) was created using the GAL22V10 programmable logic chips, LED assemblies and volt/ammeters from the PC's USB socket tester dongles. There's an additional cartridge slot installed on the top of iBolit cartridge. There one can insert any cartridge including the one with MSX diagnostics ROM (there are a few, but it would be nice to create a universal one). The GAL firmware is very primitive - if there's a high level on input, the LED connected to the output will light up. The cartridge is fairly cheap to build - maximum 12-15 Euro and is relatively easy to assemble.
The drawback is that some signals switch from high to low very fast (for example CLK), so it's impossible to see distinct LED blinking for such signals - the LED will just be lit and the brightness will depend on the frequency. With the current design it's not possible to make the blinking more visible. But that's not planned. It's enough to see that there's an activity on the signal.
A few photos of the prototype:
A few videos of prototype's test:
http://podrezov.com/ibolit/testproto1.mp4
http://podrezov.com/ibolit/testproto2.mp4
http://podrezov.com/ibolit/testproto3.mp4
The project will be put into the RBSC's repository when it's ready. No mass-production is planned at the moment.
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