Test Pattern Generator (or "TPG") was originally a freeware
application but was soon packaged on a 400k floppy diskette with Larry
Pina?s book Macintosh Repair & Upgrade Secrets (Hayden Books, 1990).
The software is intended for generating test patterns when calibrating
the video and audio output of early Macs.

Two programs are included in TestPatternGenerator.img: "128k-TPG", for
the original Macintosh, and "512k-TPG", for the Macintosh 512k or
later.

The main difference between the two is that "128k-TPG" is specifically
intended for the original Macintosh computer and its built-in 9-inch
monitor, whilst "512k-TPG" can be adjusted to display test patterns
for multiple different monitors, including custom models.
Additionally, only "512k-TPG" can be used to produce test tones for
audio calibration.

Special thanks to Jeff Walther (Trag) and tt for imaging and archiving
this software. It was previously available on another website, but it
has since gone down.

March 29, 2020 UPDATE: Added TPG-128k.dsk & TPG-512k.dsk because the
*.img file does not work as is with Mini vMac. Jeff Walther kindly
provided the original files this week, which enabled creation of these
DSK files. The DSK files boot Mini vMac and are confirmed to work on
an actual Macintosh 128K and 512K computer too. They are MacBinary
encoded, so to use them with Mini vMac, just decode them, then use the
DSK file. ?JDW

Download #4 contains version 1.06 which was released as freeware
before the publication of Macintosh Repair & Upgrade Secrets.

See Also
[Color Test Pattern Generator][1]
[Test Character Generator][2]

Compatibility
Architecture: 68k

TPG is intended for use with early Macs such as the 128k, 512k, Plus,
and SE, as well as the Macintosh XL (Lisa 2). However, 512k-TPG has
been tested to run correctly on a Macintosh LCIII with VGA output
running System 7.5.5, and tested on a Macintosh 512k with 64K ROMs,
and may run fine on other models and system versions that are capable
of running 68k software. NOTE: TPG-512k.dsk includes Macintalk in the
System Folder, but the program continues to issue regular beeps and
does not use voice at all, for reasons unknown.

  [1]: http://macintoshgarden.org/apps/color-tpg
  [2]: http://macintoshgarden.org/apps/test-character-generator