Q44491: Tandy 4000 "Invalid Configuration" after "Disk Not Ready"

Article: Q44491
Product(s): See article
Version(s): 4.50
Operating System(s): MS-DOS
Keyword(s): ENDUSER | SR# S890504-158 | mspl13_basic
Last Modified: 17-MAY-1989

It has been reported that a critical error on a floppy disk drive,
such as error 71 "Disk not ready," can change the system configuration
on a Tandy 4000 that is running QuickBASIC Version 4.50.

After a critical error occurs, the drive is unreadable by the program
or the operating system. This error causes the message "Invalid
configuration, press F1 to reconfigure," to appear the next time the
system is rebooted.

The customer reported (after checking with a Tandy source) that the
problem is caused by pin 34 (ready disk connect) on the drive
controller. Apparently, the Tandy system normally ignores this pin,
but when QuickBASIC gets the critical error, the status is changed. To
correct the problem, open the circuit for pin 34.

Microsoft has not confirmed this information.