HP 3478A Technical Manual page 137

e. e. If an If any sig y signat nature ures are i s are inco
fault. fault. Replace Replace U501. U501. If If all all signatures
keyboard can be checked by doing the following: keyboard can be checked by
1. 1. Le Leav ave th e the Si e Signa
as in step c. as in step c.
2. 2. By p By pre ress ssin ing a c g a cer erta tain f
the signatur the signature on a e on a port of port of U501 should
example, the signature on U501 pin 27 (port P10) example, the signature on U501 pin 27 (port P10)
should change from "P6H5" to "U878", if the a button is should change from "P6H5" to "U878", if the a button is
pressed. pressed. From this change, From this change, it can be
button (i.e., part of the keyboard) is inoperative or good. button (i.e., part of the keyboard) is inoperative or good.
The following lists the pin numbers of U501, the button The following lists the pin numbers of U501, the button
to be pressed, and the to be pressed, and the change in signature. change in signature.
Figure 7-D-2. Flow chart Figure 7-D-2.
ncorre rrect, U ct, U501 ma 501 may be at y be at
signatures are are correct, correct, the the
doing the following:
gnatu ture A re Ana naly lyzer zer con conne nect cted
in fro ront p nt pane anel bu l butt tton
U501 should change. change. For For
it can be determined if t determined if the
Flow chart A A
7-D-3 7-D-3
7-D-23. Calibration 7-D-23. Calibration RAM
7-D-24. If the "CAL RAM 7-D-24. If the "CAL RAM FAIL" message is di
(after a Self-Test routine), the most likely cause is a (after a Self-Test routine), the most likely cause is a
ed Calibration RAM Calibration RAM (CMOS
RAM can be checked by sending data to the RAM and RAM can be checked by sending data to the RAM and
reading it back. reading it back.
on, ,
Make sure grounded tools and wrist Make sure grounded tools and wrist
he
straps are used, when replacing or straps are used, when replacing or
checking the display. checking the display.
The test in paragraph 7-D-24 cannot be The test in paragraph 7-D-24 cannot be
made without destroying the present made without destroying the present
data in the Calibrati data in t
must be recalibrated, after doing the must be recalibrated, after doing the
test. test.
TM 11-6625-3071-14 TM 11-6625-3071-14
TM 11-6625-3071-14 TM 11-6625-3071-14
RAM Failure Failure
FAIL" message is displayed
(CMOS RAM, RAM, U512) U512) Failure. Failure.
CAUTION CAUTION
CAUTION CAUTION
he Calibration RAM. on RAM. The 3478A The 3478A
splayed
The The