HP 3478A Technical Manual page 74

3478A 3478A
nal Trigger, etc.). ). Go to Service Group nal Trigger, etc. Go to Service Group D, paragraph 7-
D-5, if any o D-5, if any of the f the failures are failures are detected.
explains the failures. explains the failures.
a. a. Turn-On Failure. Turn-On Failure. A Turn-On Failure
3478A's Keyboard Display, and HP-IB is dead (i.e., the 3478A's Keyboard Display, and HP-IB is dead (i.e., the
3478A 3478A is completely is completely inoperative). inoperative).
caused by the Main Controller (U501) and associated caused by the Main Controller (U501) and associated
circuitry. circuitry.
b. b. Inoperative Display. Inoperative Display. An In
when part or all of the 3478A's display is inoperative. when part or all of the 3478A's display is inoperative.
This can be caused by the display itself or the Main This can be caused by the display itself or the Main
Controller Circuitry. Controller Circuitry.
c. c. Inoperative Keyboard. Inoperative Keyboard.
Keyboard is when part or all of the 3478A's keyboard is Keyboard is when part or all of the 3478A's keyboard is
inoperative. This can be caused by inoperative. This can be caused by the keyboard
the Main Controller Circuitry. the Main Controller Circuitry.
d. d. Control ROM Failure. Control ROM Failure. A failure
Control ROM normally shows up as a "U.C, ROM FAIL" Control ROM normally shows up as a "U.C, ROM FAIL"
(after the (after the 3478A's Self-Test) 3478A's Self-Test). . The ROM (U502) itself can
be the cause in addition to the Main Controller (U501) be the cause in addition to the Main Controller (U501)
and latch U51 and latch U513. 3. A defective ROM A defective ROM can also show up as a
Turn-On Failure. Turn-On Failure.
e. e. U.C. U.C. RAM RAM Fails. Fails. This failure
"U.C. RAM "U.C. RAM FAIL" after t FAIL" after the 3478A's
shows that the Main Controller's internal RAM has failed shows that the Main Controller's internal RAM has failed
its self-test. its self-test.
f. f. Calibration RAM (CMOS RAM) Failure. Calibration RAM (CMOS RAM) Failure. This
failure can show up as a "CAL RAM Fail" after the failure can show up as a "CAL RAM Fail" after the
3478A's Self-Test routine. 3478A's Se lf-Test routine. The RAM (U512) itself
the cause or the Main the cause or the Main Controller Circuitry. Controller Circuitry.
g. g. HP-IB (Remote) Failure. HP-IB (Remote) Failure. This
likely caused by the HP-IB Chip (U503), but can also be likely caused by the HP-IB Chip (U503), but can also be
caused by other circuitry in the Chassis Common Logic caused by other circuitry in the Chassis Common Logic
Circuitry. Circuitry.
D, paragraph 7-
detected. The following The following
A Turn-On Failure is when t is when the
This is most likely This is most likely
An Inoperative operative Display Display is is
An An Inoperative Inoperative
the keyboard itself or
A failure caused by caused by the
The ROM (U502) itself can
can also show up as a
This failure shows u shows up as
he 3478A's Self-Test routine. Self-Test routine. It It
The RAM (U512) itself can be
This failure failure is is most
7-34. 7-34.
Group D). Group D).
normally caused by the A/D Converter or the A/D normally caused by the A/D Converter or the A/D
Controller (U462). ). Go to Service Controller (U462
he
D-31 D-31 for t for troubleshooting.
failures. failures.
a. a. Overload, Constant Zero, Floating, or Noisy
Readings. Any one Readings.
the A/D Converter or the 3478A's Input Circuitry (Input the A/D Converter or the 3478A's Input Circuitry (Input
Switching Switching or or DC/Ohms
circuitry can cause a failure, a procedure to isolate the circuitry can cause a failure, a procedure to isolate the
circuitry is in both Service Group circuitry is
definition of the failures, go to definition of the failures, go to paragraph 7-30
Failures). Failures).
b. b. A/D Slope Error.
itself or
the A/D Converter or the A/D Controller and shows up as the A/D Converter or the A/D Controller and shows up as
an "A:D SLOPE ERR", after a Self-Test routine. an "A:D SLOPE ERR", after a Self-Test routine.
the
c. c. A/D Test Fails.
by the A/D by the A/D Converter or the A/D
as an "A:D TEST FAIL", after a Self-Test routine. as an "A:D TEST FAIL", after a Self-Test routine.
d. d. Input Hybrid (U102) Failure.
Hybrid receives its set up information from the A/D Hybrid receives its set up information from the A/D
Controller, the controller can cause the hybrid to fail. Controller, the controller can cause the hybrid to fail.
p as a a
7-35. 7-35.
This failure will normally show up as an "A:D Link Fail" This failure will normally show up as an "A:D Link Fail"
(after the 3478A's Self-Test (after the
caused by the Isolation Circuitry, or either the Main caused by the Isolation Circuitry, or either the Main
This
Controller Controller
Troubleshooting information is in Service Group D, Troubleshooting information is in Service Group D,
can be
paragraph 7-D-44. paragraph 7-D-44.
7-36. 7-36.
most
Troubleshooting (Service Group E). Service Troubleshooting (Service Group E).
has some information on how to troubleshoot the power has some information on how to troubleshoot the power
supplies and Reference Circuitry. supplies and Reference Circuitry.
7-4 7-4
Floating Common Floating Common Logic Logic Failures
Floating Floating Common Common Logic
Go to Service Group D, parag
roubleshooting. The followin The following explain
Overload, Constant Zero, Floating, or Noisy
Any one of these failures can of these failures can be caused by
DC/Ohms Input Input Amplifier).
in both Service Group D and Group A.
paragraph 7-30 (DC Volts
A/D Slope Error. This failure ca This failure can be
A/D Test Fails. This failure can This failure can also be
Converter or the A/D Controlle
Input Hybrid (U102) Failure. Since
Isolation Circuit Isolation Circuit Failure Failure (Service
3478A's Self-Test routine). routine). The failure can be
(US01) (US01) or or A/D A/D
Power Power Supplies Supplies
TM 11-6625-3071-14 TM 11-6625-3071-14
Failures (Service (Service
Logic Failures Failures are are
Group D, paragraph 7- raph 7-
g explains the s the
be caused by
Amplifier). Since both Since both
D and Group A. For a For a
(DC Volts
n be caused by caused by
also be caused caused
Controller. r. It shows up It shows up
Since the the Input Input
(Service Group Group D). D).
The failure can be
Controller Controller (U462). (U462).
and and Reference Reference
Service Group Group E E