HP 16500B - Manual (Page 75)

Test the Mainframe CPU Board
1 Remove power from the HP 16500B system and unplug the power cords from both
the mainframe and the expansion frame.
2 Reinstall the bottom cover on the expansion frame. Set the mainframe on its side
with the strap handle facing up, then remove the bottom cover.
3 Plug the power cords into both the mainframe and expansion frame, then apply
power.
4 In the System Configuration menu, select Configuration. Select Test, then touch the
box to load the test system.
5 Select Test, then select Mainframe Tests. Select Option Board Tests, then select
Run-Repetitive.
6 Ground the oscilloscope probe to the metal portion of the frame near the rear panel
of the mainframe and check for TTL activity on the following pins. Reference
designator J10 is indicated on the bottom side of the CPU board.
•
J10 pins 11 through 18
•
J10 pins 21 through 28
•
J10 pins 48 through 50
If there is TTL activity on all of the pins indicated, then the mainframe CPU board is
operational.
If one or more of the signal pins on the expansion frame interface board did not
show TTL activity, then the HP 16500L or the interface cable are suspect. Using an
ohm meter, check continuity of the interface cable.
If the interface cable is good, then replace the HP 16500L circuit board.
7 Remove power from the HP 16500B system, and unplug the power cords from both
the mainframe and expansion frame. Replace the faulty components, then
reassemble the mainframe.
Troubleshooting
To test the expansion frame interface
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