Service manual

70 Diagrams
Table 6-2. Signal Name Mnemonics
Mnemonic Description Mnemonic Description
A(0)--A(15)
Address lines
MSRQ
Microprocessor service request
AD (O)--AD(7)
Address bus
NDAC
Not data accepted (GPIB)
AMB_SENSE Ambient temperature sense NEG_IMON Negative current monitor
ANA(0)--ANA(7)
Analog Signal readback bus
NRFD
Not ready or data (GPIB)
ATN
Attention (GPIB)
OV
Overvoltage
BIAS_OK
±15V bias supplies have stabilized
OV_CLR
Overvoltage clear
BOVPROG
BuFfered OV programming
OVCMP
Overvoltage comparator
BSTX
BuFfered secondary transmit
OVP_BIAS
Overvoltage protection bias
cc
Constant current status
OVPROG
Overvoltage programming
CCPROG Constant current programming OVSCR Overvoltage SCR (crowbar)
cv
Constant voltage status
PCLR
Primary power clear
CVPROG
Constant voltage programming
PREF
Primary reference voltage (2.53V)
D(0)_D(7)
Data lines
PREF_2
Primary reference voltage (1.0V)
D101--Dl08
Data lines (GPIB)
PREN
Primary remote enable
DAV
Data valid (GPIB)
PRX
Primary receive serial data
DFI Discrete fault indicator PTX Primary transmit serial data
DFI-EN
Discrete fault indicator enable
PWM_EN
Pulse width modulator enable
DPS
Downprogramming shunt
RAM
Random access memory
DN_PGM
Down programming
RDY
Ready
DRIVE_A/B
FET drive signals
REF_PWM
Reference pulse width modulator
EOI End or identify (GPIB) REN Remote enable
FAC_CAL
Factory calibration
RI
Remote inhibit
FAN_PWM
Fan pulse width modulation
ROM
Read only memory
FPRX
Front panel receive serial data
SPCLR
Secondary power clear
FPTX
Front panel transmit serial data
RX
Receive serial data
FS
Fast sense
RxD
Receive Serial Data
HSRQ GPIB service request SA Signature analysis
IFC
Interface clear (GPIB)
SRQ
Service request (GPIB)
IMON
Current monitor
SRX
Secondary receive serial data
INH_CAL
Inhibit calibration
STX
Secondary transmit serial data
IP
External current programming
TxD
Transmit Serial Data
IPROG
Current programming
UART
Universal asynchronous receive/transmit
ISEN Current sense VMON Voltage monitor
ISRQ
Interface service request
VPROG
Voltage programming
KO(0)-KO(5)
Keypad output data bus
WR
Write
KI(0)--KI(5)
Keypad input data bus
Table 6-3. Test Points
TEST POINT No. & Loc. Signal Tested Measurement and Conditions
A2 GPIB BOARD
J106-4
Primary/chassis ground Connect meter or scope common here. Make
measurements at test points 2 through 8.
U101- 1
+ 5V primary bias + 5V + 0.2V
U101-6
PCLR
Goes high for approximately 40 ms at power on,
then goes low.
U101-8
PCLR*
Held low for approximately 40 ms at power on,
then goes high.
U110-3
STX
Toggles between 0 and +5V.
U111-6
SRX
Toggles between 0 and +5V.
U119-4
FPRX Toggles between 0 and +5V.
U119-18
FPTX
Toggles between 0 and +5V.