Picked up a new PCjr in good condition, except that it doesn't boot!

[sgifanatic]

Got lucky today and found a PCjr still in the original box, with the diskette drive safety card insert still present! The pics will do most of the talking, but I got the IR keyboard, two joysticks, power adaptor and the PCjr system unit itself. No sidecars or other expansions, however.

Without further ado, here is the young man:







Of course, the issue I'm having is that I can't seem to boot this with a 360k DOS boot floppy that was working fine in the Commodore PC10 (8088). I get an Error H, which I understand from searching the forum and Mike Brutman's PCjr site, is a disk error. Other than some very elementary exposure to a PCjr at the age of 6 or 7, I've never used or owned one before, so am the furthest thing from an expert.

I did ensure that all cables and cards were properly plugged in. The drive does seek, and the keyboard also works. Post floppy boot failure, the system goes into ROM BASIC just fine (see pic below).

Any thoughts? Do I need a specific DOS version for PCjr?

 

[sgifanatic]

The obligatory BASIC three liner...

 

[Stone]

Try cleaning the heads. Just a guess but thirty years of sitting idle could possibly have allowed the heads to get crusty.

 

[sgifanatic]

Always sound advice. The heads were ok, but I've watched the seek over and over and determined that there appears to be a minor slip in the drive. The heads end up in an unexpected place and that's what causing this. I think this is fixable as I have been able to loosen the drive enough to where I've seen a "Starting MS-DOS..." message. It gets stuck after that. Probably because this system has 128KB of RAM and I've got a DOS 5.0 floppy in there. I believe 6.22 had a minimum RAM requirement of 512KB, so I would be surprised if 5.0 isn't pretty close.

Will try a little bit of WD-40 along the drive gear and shaft, as well as a DOS 3.3 boot floppy.

 

[jmetal88]

It might be a problem with your drive cable. I've gotten Error H on my PCjr several times due to the 2-drive cable I hacked together. It is a disk error, but I think it's more of when the controller to drive communications aren't going as expected.

 

[ClassicHasClass]

I gotta find a spot for my Peanut to be out and play instead of sitting in its hard case. It's a fun machine because of its quirks.

 

[jharre]

Does it make noise when the heads are seeking? Many old floppy drives end up with dried lubricant gunk on the rails that the heads slide on.

A cotton swab with a little WD-40 on the parallel metal rod rails will often free up the head mechanism. With the power off, you can gently slide the assembly front and back to clean both ends, top and bottom. I hear that a better long-term lubricating solution is a product called Dri-Slide.

Jim

 

[Trixter]

ERROR H is a generic diskette read error and so far you're doing everything correctly. The drive rails gum up over the years and a complete rail clean and re-lube almost always fixes the problem. If the belt is slipping, there is a small amount you can adjust the tensioning but there was a PCjr Forum (http://www.brutman.com/forums/) post a few years ago that had a source for new belts. The fact that you are getting closer to booting means you're doing the right thing.

Those Qume drives are generally considered low-quality... but the more I've had to repair them, and found them very well-documented and very easy to service, the more I have mentally upgraded them to "medium" quality

Don't boot DOS 4 or later because those DOSes require patching and will hang on boot. Boot DOS 2.11 through 3.3. You can use later DOSes but you'll need to patch them using ftp://ftp.oldskool.org/pub/misc/Software/PCjr/PATCHDOS.ZIP before trying to boot them.

Now that you own a PCjr, you should grab ftp://ftp.oldskool.org/pub/misc/Hardware/IBM/IBM PCjr Hardware Maintenance and Service.pdf and probably everything else in that directory.

 

[vwestlife]

Make sure you don't use it in front of a CFL light bulb!

 

[sgifanatic]

Thanks, Trixter. Will grab those patches and the PDF. Appreciate the links.

I'll get a chance to work on this some more over the weekend. Am pretty sure at this point the mechanical drive/shaft/gears are the issue and cleaning/wd40 seems a good fix.