It's really worth while removing and cleaning the ZIF sockets as they suffer from oxidation and dry joints from years of kids pulling the Program Memory in and out.
Also redo the input and output connectors as I've had a few where a hairline crack develops and cuts power to some of the mainboard.
I sent Hans the workbook from my father's system he used to teach with. I've got a huge pile of of this stuff![:lol:]( "Laughing")
I would suggest doing some preventative maintenance that will make the system far more reliable. My golden test is to code up a simple 6522 timer interrupt that increments the output register every second, then bang the board around and see if it crashes.
It is this instability that was the bane of these Unilab systems BITD and prevented them from being like a true SBC. Once fixed up, I can use the burner to write an EPROM and leave it running for days without any trouble.
I was going to create a shift register controlled Starburst Display module for this with ten digits but I messed up the design and didn't realise that half a 16 segment display is still a lot of current, so I need a strong 5V supply to drive it and I put it on the back burner. I was driving it successfully from a Pi and a BBC so it could work in theory.
I really wish they used a 6502 and a 6522 for the Program Loader.
Also redo the input and output connectors as I've had a few where a hairline crack develops and cuts power to some of the mainboard.
I sent Hans the workbook from my father's system he used to teach with. I've got a huge pile of of this stuff
I would suggest doing some preventative maintenance that will make the system far more reliable. My golden test is to code up a simple 6522 timer interrupt that increments the output register every second, then bang the board around and see if it crashes.
It is this instability that was the bane of these Unilab systems BITD and prevented them from being like a true SBC. Once fixed up, I can use the burner to write an EPROM and leave it running for days without any trouble.
I was going to create a shift register controlled Starburst Display module for this with ten digits but I messed up the design and didn't realise that half a 16 segment display is still a lot of current, so I need a strong 5V supply to drive it and I put it on the back burner. I was driving it successfully from a Pi and a BBC so it could work in theory.
I really wish they used a 6502 and a 6522 for the Program Loader.
Statistics: Posted by maniacminer — Sun Jun 29, 2025 12:57 am