HP 8340B Manual page 257

SHIFT M4
When to Use SHIFT M4
After you have determined the failure mode (using the processor self test LEDs and Table F-3),
you can use the
SHIFT M4
diagnostic to further isolate
the failure. This service diagnostic tests
DACs and
control circuitry
in the instrument, and allows the results of the self test to be displayed
in the front panel
ENTRY DISPLAY.
What SHIFT M4 Does
SHIFT M4 does not perform exhaustive DAC tests, but provides
an indication to direct
your
troubleshooting to
a
specific device or circuit path.
Table F-4 lists all the tests performed when
you press
[SHIFT] [M4].
As you can see, this service
diagnostic tests more than just the A60 assembly. All of the tests are listed because only one test
(0)
is not dependent on the test results of
one or
more of the other tests.
The Interdependence of the SHIFT M4 Tests
Table F-5 illustrates the
interdependence of the SHIFT M4
tests. The
vertical axis (Test
Number) lists
the tests,
0
through
31.
The horizontal axis (Dependent
On) lists the test numbers and indicates which
test(s) must pass for
a
given
test result
to be valid. An
X
in
a
Dependent
On column indicates that
a
given test is
valid only if
the test in
that
column also
passes.
Example:
Test
11 is
only valid
if
tests
0, 5, and 6
pass.
If
test
11 fails, verify
that tests
0, 5, and 6
have passed
before
troubleshooting the assembly exercised in
test
11.
SHIFT M4 Test Procedure
1.
Press [SHIFT]
[M4].
While the tests are running, the
ENTRY DISPLAY shows DIAGNOSTIC TESTS IN PROGRESS.
When the tests
are
through, the instrument displays
TEST:?FULL DIAGNOSTIC
and then displays
PASS or FAIL. PASS indicates that
all of the tests related to this
diagnostic have passed. FAIL
indicates that one or more of the tests failed.
2.
If
the display indicates FAIL, use the
RPG
or the step keys to
move
through the test results and
determine which test(s) failed.
HP 8340B/41B
A60
Processor Assembly-Level Troubleshooting F-19