Mike's PCjr Page

A lot of people have reported email from me going into their spam folders. I am not sure why. I am suuuuper anal about my mail server and passing all the gates to not get blocked by receivers. I also get passing dmarc acknowledgements each month from all the major mail handlers. If you are expecting...

...the area from B8000 to BFFFF is aliased to the actual video area. So it seems that the designers intended it to work the way Tandy computers do and it is a bug. That is confusing. 1) Tandy doesn't alias and 2) Tandy came after. The strobe gates for the VGA chip are controlled by a PROM. Someone ...

'Bug' categorization is subjective. I'm not sure if CGA aliases the lower 16KB at BC000 or not or if it even drives the bus at BC000. If so, I suppose the aliasing on the Jr could be intentional. I suspect CGA does not and the Jr aliasing artifact was just a cost decision as a correction would requi...

Brutman wrote:...nobody in their right mind...

and 'posting on this forum' go hand in hand.

Careful about partitioning and formatting a DoM or HD in another machine then moving it to the JR. The JR-IDE BIOS always enables LBA and divides the total sector count by 63 SPT to get heads/cylinders. Whatever tool you use externally may not use that algorithm or do translation at all. I would get...

Do you have a JR-IDE? Do you get any POST writes?

Brutman wrote:

• The two pins from the motherboard to the original power supply card are left free with this new setup. Is this going to be a problem? (I need to check the tech ref to see what they do.)

They are just mechanical anchors. Nothing electrically conductive.

They snap on. Not sure when they were introduced but I only have one set between all my Jrs.

Not really. I never intended to build them for sale. However I 'think' I have the parts for a few more. I need to check. I'll reply here probably tomorrow (Sunday Dec 9) if I have enough for a few more. The TandyMOD+ replaces ZM31 with a small carrier board with a SMT 16v8. It does require you to de...

Does anyone here with a keen interest in Jrs (and who wouldn't?) live in Europe, Great Britain, or Hong Kong? If so, please drop me a PM.

Actually if you live in any country with 240V 50 Hz A/C mains with a European CEE 7/16 or British BS1363A power outlet standard, that would work too.