A20 Digital Motherboard Removal (For Serial Prefix My433 And Later); Tools Required; Procedure - Agilent Technologies E4991A Service Manual

A20 Digital Motherboard Removal (for serial prefix MY433
and later)

Tools Required

• Pozidriv screwdriver, pt size #1 (small)
• Torx screwdriver, T15

Procedure

Step 1. Remove the mouse, the external keyboard and the parallel printer cable if they are
connected to the rear panel.
Step 2. Remove the outer cover as described in "Outer Cover Removal"
Step 3. Remove the power supply as described in "A50 Power Supply Assembly Removal (for
serial prefix MY433 and later)"
Step 4. Disconnect the following cables.
• A26 to A20 Digital Motherboard floppy flat cable (item 1 in Figure 6-16 on page 260 )
• A26 to A20 IDE1 flat cable (item 2 in Figure 6-16)
• A26 to LCD mylar ribbon cable (item 4 in Figure 6-16)
• A26 to Floppy mylar ribbon cable (item 7 in Figure 6-16)
• A26 to A27 Mass Storage Disk Drive flat cable (item 8 in Figure 6-16)
• A26 to Backlight primary cable (item 9 in Figure 6-16)
• A21 to the A10 Analog Motherboard flat cable (item 3 in Figure 6-16)
• A21 to the A22 Front Panel Keyboard flat cable (item 10 in Figure 6-16)
• A21 to the system fan cables
Step 5. Remove the following boards.
• A21 Analog Interface board as described in "A21 Analog Interface Board and
EEPROM Removal"
• A24 GPIB board as described in"A24 GPIB Card Replacement (for serial prefix
MY433 and later)"
• A26 Display board as described in "A26 Display Board Removal"
Step 6. Remove five screws fastening the A20 to the bottom panel and remove the A20.
NOTE To replace the A20, reverse the above procedure. And, configure the several jumpers and
BIOS parameters as described in "To Configure the A20 Digital Motherboard and BIOS
(for serial prefix MY433 and later)" on page 210.
Chapter 7

A20 Digital Motherboard Removal (for serial prefix MY433 and later)

Replacement Procedure
293