I have uploaded diags.zip to the cbm area.  This is a D64 file of my
diagnostic disk.  These are diagnostic programs for the various Commodore
machines that I have been using.  Some of them I have written myself.
Some are modified versions of Commodore routines.  Some may have come from
other sources.  I have been collecting these routines for 30 years, and
don't remember where they all came from.

ROM tests:  The various ROM test routines are all modifications of
Commodore's ROM test routine for the PET. In the Commodore routine, a
black rectangle appears on the screen if a ROM is defective.  I have
turned this around.  As the program starts, a black rectangle appears for
every ROM version (for North America). The routine calculates the checksum
for every ROM version.  If it doesn't match, the corresponding rectangle
is blanked out.  You should end up with a rectangle for every ROM.  If a
ROM is missing, it is defective.  The main use for these routines is to
detect intermittent ROMs.  You can let it run as long as necessary.
Sometimes it takes days to find an intermittent ROM.

RAM tests:  The various RAM tests are all modifications of the Dynamic RAM
test for the PET.  The routine attempts to determine the amount of memory
in the machine, and then test whether it will hold its contents for
various numbers of cycles. The Commodore test doubled the number of cycles
each time it writes the memory.  I found this too slow and modofied it to
multiply the number of cycles by 10 each time through.  These are also
used primarily to find intermittents.

Address checker is a short routine to find faulty address or data drivers.
It write numbers to memory and reads them back. If it finds an error, it
writes the address and memory difference to the screen. If the memory was
high when it should be low, the number is positive, the memory was high
wheit should have been low.  If the number is negative, the memory was low
when it should be high.  analysis of the bits of the address and memory
data can indicate potentially defective drivers.

Screen Alignment is the Commodore alignment routine for the 40 column PET.
I don't remember if it also works on 80 column screen.

TV Test puts various test patterns on the screen, and is used to adjust
the rf modulator for best picture.