This document contains information about the utilities provided with Mac OS 9.
My favorite may be the 5xxx/6xxx Tester:
This program tests Performa and Power Macintosh 5200, 5300, 6200, and 6300 computers for a possible hardware problem. If you have a Performa or Power Macintosh 5200, 5300, 6200, or 6300 series computer, you should use the tester before installing Mac OS 9. See the document inside the Tester folder for instructions on using the tester.
IMPORTANT: The Power Macintosh or Performa 6320, 6360, and 5260 computers do not have this hardware problem. If you have a Power Macintosh or Performa 6320, 6360, or 5260 computer you do not need to use the tester program.
The document doesn’t get into what the hardware problem is, but this 1996 article from CNET shines some light on the issue:
As CEO Gil Amelio prepares to unveil a turnaround plan for the company next week, Apple Computer suffers more bad news, this time hardware defects that are forcing the company to recall certain models of Power Macs, Performas, and PowerBooks.
The company yesterday notified its resellers of hardware problems in various Macintoshes, including the 5200 and 5300 Power Macintoshes; PowerPC-based Performas with the model numbers 52xx, 62xx, 53xx, and 63xx; and PowerBook 5300 and 190s.
[…]
Apple is describing its response as a “repair extension program” rather than a full-fledged recall because it is not asking Power Macintosh and Performa users to send their computers into the company. Instead, Apple said it will pay for repairs–which include unexpected freezes and intermittent changes in a monitor’s hue–when a user takes the system into an authorized service shop.
Apple is encouraging users to take care of the problems now but will continue to reimburse for repairs up to seven years after the company stops manufacturing both systems, whenever that occurs.
Apple is ordering a full recall, however, of the PowerBook models, asking dealers to return all unsold stock. Users also will be asked to send their PowerBooks–which have cracks in the plastic casing near the display hinge and problems with AC connectors–to a central Apple repair depot. Users can expect repairs to take less than two weeks, according to spokeswoman Nancy Morrison.
The PowerBook 5300 model appears to be jinxed. Last fall, workers discovered a battery defect in the model that could cause it to catch fire.