Agilent Technologies 4284A Service Manual page 155

4-20. A31 HANDLER I NTERFACE (OPT.202) SERVICE SHEET
4-20-1 . CIRCUIT DESCRIPTION
The A3 1 handler interface board consists of photo couplers, and peripheral interface adapt­
ers (P IAs).
[ Photo Couplers ]
Photo couplers A3 1 U1 through A3 1 U 1 4 opto-isolate the i n put and output signals. Then
timing of the input/output signals is determined by setting j umpers A3 1 W3 through A3 1 W1 3 .
For more detail information about the input/output signals a n d the jumpers, refer t o the
handler interface operation note in the HP 4278A Operation M an ual .
[ Peripheral Interface Adapters ]
Peripheral interface adapters ( PIAs ) A3 1 U 1 9 and A3 1 U20 interface between the A7 C P U
board and the A3 1 board .
4-20-2. TROUBLESHOOTING AIDS
The test pOints are listed in Table 4-A3 1 -1 .
Test Point Signal Name
A31 TP1
A31 TP2
A31 TP3
A31 TP4
4-20-3. REPLACEABLE PARTS LISTS
The replaceable parts for the A3 1 Handler I nterface board are listed in Table 4-A3 1 -2 .
4-20-4. COMPONENT LOCATIONS
The component locations on the A31 H an dler I nterface board and the board connector pin
assignments are shown in Figure 4-A3 1 - 1
4-20-5. SCHEMATIC DIAGRAMS
The schematic d iagram of the A3 1 handler interface board is shown in Figure 4-A3 1 -2.
Table 4-A3 1 -1 . Test Point List
Description
G round line
CND
+5 V
DC
+5 V
BE
792 kHz Clock signal
START I N signal
.
4-A31-1