Wyse WY-60 Maintenance Manual page 54

ACTION
11. Press the F10 key again.
12. Wait until the screen displays
the scrolling ASCII test
pattern, then hold down the
SPACE BAR until the test pattern
stops flashing.
13. Call test pattern 0 by
pressing the CTRL and A
keys simultaneously.
COMMENTS
This saves the selection
you've made and starts
the diagnostic self-test.
You should see a flashing
test pattern of
asterisks.
You will see test
pa t tern M.
You can toggle between
patterns 0 and M with the
CRTL A keystroke command.
Both test patterns are
described and illustrated
in "Test Pa tterns" in
this chapter.
When toggling between
test patterns 0 and M,
you will find another
pattern--the character/
attribute test pqttern.
It contains several rows
of characters, each
displayed wi th a
different attribute.
Look at this pattern when
you are troubleshooting.
You should not depend on
measurements from this
test pattern during
alignment.
14. Use the DVM to check the +5V
supply at R20 on the terminal
PCB. The keyboard socket is
ground.
See
Figure 4-1, "Power
Supply Component Layout."
15. Adjust VR101 until the digital
voltmeter reads +5V +2 percent.
4-7
If you can't adjust the
power supply into
tolerance, see
"Troubleshooting,"
Chapter 3.