Keithley 2750 - Display Board

4-6 Troubleshooting Model 2750 Multimeter/Switch System Service Manual
Display board
Display board components are shown in the digital circuitry block diagram in Figure 4-2.
Figure 4-2
Digital circuitry block diagram
O
P
T
O
I
S
O
U175
U150
U155
68332
μP
U135
XADTX
XADCLK
XADTS
XADRX
ADTX
ADCLK
ADTS
ADRXB
Analog
Circuitry
(See
Figure 4-3)
Display Board
Controller
U401
Display
DS401
Trigger
U146
Trigger
Link
TRIG IN
TRIG OUT
NVRAM
U136
ROM
U156, U157
RAM
U151, U152
U164, U193
XTAL
Y101
RS-232
U159
RS-232
Port
GPIB
U158, U160,
U161
IEEE-488
Bus
IN
OUT
Data IN
Data OUT
Keypad
Slot
Control
Battery
Back
Control/
Realtime Clock
U171
BAT
BT100
Y103
U122
U127
U170
U173
U174
U195
U196
Digital Output
U188, U189
Digital Input
U146, U191
U192
Digital OUT
Digital
I/O
Line Sync
Control
U179
U180
U181
U182
U183
U184
U186