Agilent Technologies 4284A Service Manual page 145

4-1 8. A20 H P-IB INTER FACE SE RVICE SHEET
4-1 8- 1 . CI RCU IT DESCRIPTION
The A20 H P- I B I nterface board hand les all H P- I B interface functions. The H P- I B I nterface
board controls the handshaking between the M icroprocessor and external H P- I B controlled
equipment.
4-1 8-2. TROUBLESHOOTING AIDS
The test points are listed in Table 4-A20-1 .
Test Point
A20TP1
A20TP2
A20TP3
A20TP4
4- 1 8-3. REPLACEABLE PARTS LISTS
The replaceable parts for the A20 H P- I B Interface board are listed in Table 4-A20-2.
4-1 8-4. COMPON ENT LOCATIONS
The A20 HP-IB I nterface board component locations are shown in Figure 4-A20-1 .
4-1 8-5. SCHEMATIC DIAGRAMS
The A20 H P- I B I nterface board schematic diagram is shown in Figure 4-A20-2.
Table 4-A20-1 . A20 Test Points
Signal Name
CND
+5 V
LDS
4MH::;
4-A20-1
Description
Ground reference for the
supply
V digital supply
+5
Lower Data Strobe Signal
4 MHz is counted down from the A7
/CLK I 6 M H :::
V digital
+5