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Now that I have my machine mostly working, I want to try to load Basic through the serial port. I have the basic Hex that I downloaded from the net so I'm ready to go. My questions are: - Do I load Basic at $A000 onwards - Do I then launch Basic from with a .A000G ? I have seen reference on the web ...

Re Drives again: I forgot to mention that the machine came with a funky little adaptor board attached to J4. No idea what it does. See attached images:

Thanks for moving the thread, and thanks for the info on both the drives and the RAM boards. Regarding the RAM boards: My present switcher supplies 5V @ 5A. so it may not be enough to power the second card. I have already ordered another switcher from ebay (cheap $25). This is the switcher I was goi...

SUCCESS! I decided to wire up a serial connection on the off chance the board was already jumpered for it...well, what do you know, it worked! http://web.mac.com/lord_philip/other_computers/OSI_C2-4P_Fix.html#19 Now that the main machine is fixed (although I'm still having issues with the other 24k ...

Firstly, apologies. Seems I posted this thread in completely the wrong place. Hopefully Dave can move it somewhere more appropriate. Hi Steve, yes the switcher seems to work quite well. The one I have does get quite hot. Hopefully once the case is all fixed up and everything is back inside, the fan ...

After a bit of searching it seems that the two wires that come off the keyboard do connect to the reset circuit which are triggered by the 'Break' key. Please let know if I'm mistaken.

Thanks to Mark Csele for pointing out the error of my ways. I was assuming that the machine had reset on power up, but like many machines of that era it was manually triggered. It's been soooooo long since Ive used a OSI machine I have forgotten all this stuff.I'm 42 now, and was maybe 10 when I use...

Well, I've made a lot of progress in one day. I now have the prompt, and even ran a very small program from the monitor. I'm not getting reset on the CPU, so I have to force it by briefly grounding pin 40 of the 6502. Can anyone point me in the right direction on where (and how) to look for the faul...

Hi everyone, This is my first post here. Some of you may know me as that annoying guy trying to track down an OSI machine...well, I finally got one, but it's a real 'fixer-upper' for sure. The machine arrived yesterday and smelt bad like mouse poop. I decided the first thing was to take it apart and...