Mike's PCjr Page

Since I've been unable to find a comprehensive list of the various PCjr diagnostics tests, here's what I've been able to confirm on my own hardware:

1 Diskette Drive Test (drive 1)
2* Diskette Drive Test (drive 2)
3
4 Television and 40 Column Display Test (plus 16k graphics modes up to 300x200)
5 Light Pen Test
6 Attachable Joystick Test
7
8 80 Column Display Test (plus all graphics modes)
9 Sound Test
0
A Graphics Printer Test (LPT1)
B* Graphics Printer Test (LPT2)
C Parallel Printer Attachment Test (LPT1) (Service Mode)
D* Parallel Printer Attachment Test (LPT2) (Service Mode)
E Joystick Port Test (Service Mode)
F
G Modem Test
H* Compact Printer Test
I RS232 Test (Service Mode)
J Keyboard Test (62-key)
K Keyboard Test (83-key)
L* Cluster Attachment Test
M* Cluster Status Test
N* Speech Attachment Speech Test
O* Speech Attachment
P* Speech Attachment Microphone Test

Items with * only appear when option is attached.

For the tags I can't confirm:
3: I assume this is for the third floppy drive the BIOS supports.
O: I have no idea what this is actually testing, and I don't have the additional pages for the Guide to Operations that came with the Speech Attachment that cover the tests.
0, 7, F: Are these used by anything? I can see there not being a 0, but 7 and F are suspiciously empty

Did you consult ftp://ftp.oldskool.org/pub/drivers/IBM/ ... ervice.pdf ? It might have a complete list of tests.

Documentation for the Speech sidecar is here: ftp://ftp.oldskool.org/pub/drivers/IBM/ ... 20Sidecar/

It might be impossible to determine what the additional diag letters are, since BIOS extensions (sidecards, etc.) added themselves to the diagnostics during POST. So the only way you'd figure out what F is, for example, is if something was attached that registered F.

Since you've tested both cluster and speech sidecars, I don't think there are any additional letters/diags to discover.

OK. The BIOS show 3 as being a floppy test, and 7 being a joystick test, but was unused. I can't help but wonder if F was going to be another joystick port test.

FYI, the joystick test (and other tests) might fail if the PCjr is sped up. The BIOS joystick support doesn't return the correct ranges if an NEC V20 or a speedup mod is performed... but then again, this shouldn't be a surprise, if you think about it.

Or if you've ever tried to play an old enough game that uses a joystick on a faster PC.

Right. Prior to 1984, there weren't faster systems, not even announced. And for the PCjr, there was no intention ever to speed up the system.