HP 3478A Technical Manual page 85

3478A 3478A
7-D-1. INTRODUCTION 7-D-1. INTRODUCTION
7-D-2. This Service Group 7-D-2. This Service Group has the
Logic Circuitry troubleshooting information for the 3478A. Logic Circuitry troubleshooting information for the 3478A.
Unless otherwise specified, refer to Schematic 1 when Unless otherwise specified, refer to Schematic 1 when
using the troubleshooting procedures. using the troubleshooting procedures.
7-D-3. The 3478A Logic Circuitr 7-D-3. The 3478A Logic Circuitry can be separ
two major circuitry: Chassis Common Logic Circuitry and two major circuitry: Chassis Common Logic Circuitry and
Floating Common Logic Circuitry Floating Common Logic Circuitry. . The Chassis Common
Logic Circuitry consists of the Main Con- troller (US01), Logic Circuitry consists of the Main Con- troller (US01),
Control ROM (U502), Calibration RAM (CMOS RAM, Control ROM (U502), Calibration RAM (CMOS RAM,
U512), HP-IB Chip (U503), Display, Keyboard, and U512), HP-IB Chip (U503), Display, Keyboard, and
associated circuitry. associated circuitry.
operation of of the operation the instrument. instrument.
Logic Circuitry consists of an A/D Controller (U462), A/D Logic Circuitry consists of an A/D Controller (U462), A/D
Converter (U403, U401, etc.), and associated circuitry. Converter (U403, U401, etc.), and associated circuitry.
Its purpose is to control the A/D conversion, and to Its purpose is to control the A/D conversion, and to
control the Input Hyb control the I nput Hybrid. rid. Com- munications betw
circuitry are done by circuitry are done by the Isola- tion Circuitry the Isola- tion Circuitry
7-D-4. 7-D-4. Most of the Most of the procedures in this Ser procedures in this Service Group re-
quire a Signature Analyzer for troubles quire a Signature Analyzer for troubleshooting.
tion to it, a logic probe and a tion to it, a logic probe and a logic pulser are also re-
quired for some quired for some troubleshooting procedur troubleshooting procedures.
required equipment, before going to the procedures. required equipment, before going to the procedures.
A/D CONVERTER AND LOGIC TROUBLESHOOTING A/D CONVERTER AND LOGIC TROUBLESHOOTING
Service Group D Contents Service Group D Contents
T T i i t t l l e e
Introduction ......... Introduction
Chassis Common Logic Troubleshooting and Chassis Common Logic Troubleshooting and
Failures........................................................ Failures........................................................ ....7-D-5
Pre-Troubleshooting Information Pre-Troubleshooting Information ..........
Turn-On Failure................................................... Turn-On Failure................................................... ...7-D-9
Inoperative Display Inoperative
Inoperative Keyboard..................................... Inoperative Keyboard..................................... ... ... 7-D
HP-IB Failure HP-IB
U.C. ROM Fails U.C. ROM
U.C. U.C. RAM Fails
Calibration RAM Calibration
Voltmeter Complete................. Voltmeter
Address Address Switch
External Trigger External
Floating Common Logic Failures Floating Common Logic Failures ..........
Pre-Troubleshooting Information Pre-Troubleshooting Information ..........
A/D Converter Failures and Tr A/D Converter
Input Hybrid Input
A/D Controller Troubleshooting ......... A/D Controller Troubleshooting
Isolation Isolation Circuitry
has the A/D Convert A/D Converter and
y can be separated into
The Chassis Common
Its purpose Its purpose is is to to control control the
The Floa The Floating ting Common Common
Com- munications between the
vice Group re-
hooting. In In addi-
logic pulser are also re-
es. Obtain the Obtain the
SERVICE GROUP D SERVICE GROUP D
.................. .................. .................. ..................
Display ......... .................. ..................
Failure ......... .................. .................. ..................
Fails.................. ....................................
RAM Fails ........ ................. ..................
RAM Failure....... Failure................
Complete..........................
Switch Failure Failure ......... ..................
Trigger ........ ................. ..................
Failures and Troubleshooting
Hybrid (U102) Inoperative............. (U102) Inoperative......................
Circuitry Troubleshooting.. Troubleshooting............
er and
The instrument contains CMOS Integrated Circuits The instrument contains CMOS Integrated Circuits
which are extremely susceptible to failures due to which are extremely susceptible to failures due to
static static discharge.
grounded tools and wrist straps be used when grounded tools and wrist straps be used when
ated into
handling or troubleshooting these components. handling or troubleshooting these components.
7-D-5. CHASSIS 7-D-5.
TROUBLESHOOTING AND FAILURES TROUBLESHOOTING AND FAILURES
7-D-. 7-D-.
the
Common Logic Failures and Troubleshooting. Common Logic Failures and Troubleshooting.
7-D-7. 7-D-7. Pro-Troubleshooting
7-D-8. 7-D-8.
een the
Logic Circuitry, check and do the following: Logic Circuitry, check and do the following:
a. a. Check th Check the + 5V Powe
good. good. The supply sho
addi-
V. V. If the supply If the supply is inoperative, go
troubleshooting. troubleshooting.
b. b. Make sur Make sure the ALE li
shown in Figure 7-D-1 shown in
7-D-1 7-D-1
P P a a r r a a g g r r a a p p h h
.................. ............ ... ...7-D-1 ...7-D-1
....7-D-5
.................... ........... . ...7-D-7 ...7-D-7
...7-D-9
.................. ............. .... ... ... 7-D 7-D-13
7-D-15
.................. ............. .... .. ... . 7-D 7-D-17
........................... ......... .. ... . 7-D 7-D-19
.................. .................. .......... . .. ... . 7-D 7-D-21
.................. ................. ........ ... ... 7-D 7-D-23
.................. ............ ... .... .... 7-D-2 7-D-25 5
................. ................ ........ ... ... 7-D 7-D-27
.................. .................. .......... . ... ... 7-D 7-D-29
.................... ............ .. ... ... 7-D 7-D-31
................... ............ ... 7-D 7-D-33
oubleshooting . . .. .. 7-D 7-D-35
......... .. .. 7-D 7-D-40
................... ............ .. ... ... 7-D 7-D-42
.................. ........... ... 7-D 7-D-44
discharge. It It is is especially imp
CHASSIS COMMON COMMON LOGIC LOGIC
The The following following paragraphs paragraphs have
Pro-Troubleshooting Information
Before Before troubleshooting troubleshooting the
e + 5V Power Suppl r Supply and ma
The supply should be betwe uld be between + 4.9V and + 5.1
is inoperative, go to Service Group E for
e the ALE line at U501 p ne at U501 pin 11 is good
Figure 7-D-1. . If the s If the signal is missing
TM 11-6625-3071-14 TM 11-6625-3071-14
-13
-15
-17
-19
-21
-23
-27
-29
-31
-33
-35
-40
-42
-44
especially important ortant that that
have the the Chassis Chassis
Information
the Chassis Chassis Common Common
y and make sure it is ke sure it is
en + 4.9V and + 5.1
to Service Group E for
in 11 is good, as , as
ignal is missing or wrong, or wrong,