Mike's PCjr Page

I have recently pulled jr out of mothballs, after an extended period of time. Gosh, the things I have forgotton! The first problem I experienced, is a constant vertical roll , that will intermittently return to normal. I found what I am guessing was the last boot disk I was using, it is labeled MS DOS 3.3 - jr hotshot version 3.2, I was able was able to boot from it several times. After several reboots, I would get an error j, and then after a few more reboots, the process would stop with some ascii charactors displayed. Anyone have advice for me?

Do you have your guide to operations handy? Error 'J' is supposed to be related to the speech adapter.

If you have sidecars on the system I would remove them all and then run diagnostics. Ctrl-Alt-Ins if you don't remember. You will need to refer to the GTO (Guide To Operations) on how to run the different tests.

If the base machine checks out ok, then start adding sidecars back on. Test them as you do it.

Lastly, be careful not to bend any pins.

Boot problems solved, thx for your help. My boot disk must be bad...... Really surprised I don't have a back up. Sooooooooo, now I can boot from my DOS 2.1 disk. Could I buy a DOS 5.x disk from you? Need to re-learn what device drivers and such I will need to add. Also... could I trouble you to remind me of the differences between cartridge basic and basic loaded from disk? Thx in advance.

bbter wrote:Boot problems solved, thx for your help. My boot disk must be bad...... Really surprised I don't have a back up. Sooooooooo, now I can boot from my DOS 2.1 disk. Could I buy a DOS 5.x disk from you? Need to re-learn what device drivers and such I will need to add. Also... could I trouble you to remind me of the differences between cartridge basic and basic loaded from disk? Thx in advance.

I think the BASIC Cartridge just frees up some of the system memory when you are using BASIC since it can use the cartridge instead of main memory.

There are a few ways to get a DOS 5 boot disk.

If you have a 'modern' machine that has a 5.25 inch drive on it too, then I can email you an image of the diskette. That lets you create the diskette locally, and nothing has to go through the mail. If you have DOS 5 you can do the patches yourself. I think I have the patch procedure posted. If you absolutely have no other way to do it, then I guess we mail diskettes.

The absolutely necessary device driver for anything more than a 128K PCjr is JrConfig. That's been my favorite for 20 years.

Here are the levels of BASIC:

• Cassette BASIC - built in, no diskette support
• Disk BASIC (basic) - diskette support, missing some 'advanced features'
• Disk BASICA (basica) - diskette support with 'advanced features'
• Cartridge BASIC - with disk (or without disk, no difference) and supports PCjr video and sound

You normally can't run the disk BASICs on a PCjr because DOS is looking for the 'BASIC' or 'BASICA' command and will tell the machine to use Cartridge BASIC instead. Which is a real bummer if you don't have the cartridge inserted. To get around this rename 'BASIC' to 'DBASIC' or 'BASICA' to 'DBASICA', and that will fool DOS. Anything you do in those versions of BASIC will be compatible with normal PCs. Some things you do in Cartridge BASIC are PCjr only and will not work on other machines.

As pointed out, Cartridge BASIC is in a ROM so it saves a little bit of RAM.