Agilent Technologies 4284A Service Manual page 126

4-14-2. TROUBLESHOOTING AIDS
Since the A7 board has been set up under the exchange program, when the A7 board is
defective, you replace the A7 board. The board isolation procedure is given in SECTION 3.
4-14-3. REPLACEABLE PARTS LIST
The replaceable parts for the A7 board are divided into two groups: a ROMIess A7 board and
a set of programmed ROMs. This protects against the mismatching of ROM versions be-
tween the replaced CPU board and the defective CPU board. O n l y the ROMless A7 board
has been set up under the exchange assembly program. I f the A7 board is defective without
ROMs installed and the ROMs are not defective, order a ROMless A7 board. (Install the
ROMs from the defective A7 board on the replacement A7 board.) I f both the A7 board and
the ROMs are defective, order a ROMIess A7 board and the four ROMs.
The replaceable parts for the A7 board are listed in Table 4-A7-2. T h e part number for a
rebuilt exchange board is listed on the first page of the A7 board's replaceable parts list.
4-14-4. COMPONENT LOCATIONS
The component locations for the A7 Digital Control Board are shown in Figure 4-A7-1.
4-14-5. SCHEMATIC DIAGRAMS
The A7 Digital control Board's schematic diagram is not supplied since of the ROMIess A7
board has been set up on the exchange assembly program.
4-A7-2