HP 70908A, Service Manual

Page: 305 / 335

A12 Controller
CA UTION
This module contains components that can be damaged or destroyed by
electrostatic discharge . It should be serviced at a static-safe workstation.
(Refer to \Preparing a Static-Safe W ork Station " in Chapter 4.)
T o Remove the A12 Controller
1. Remove the module cover . (Refer to the \Module Cover " procedure .)
2. Disconnect the following cables:
W1 (1) from A12J7
A14 front panel board ribbon-cable (2) from A12J6
W2 (3) from A12J2
W6 (4) from both A9J2 and A12J3
W13 (5) from A12J4 and A11J7
W5 (6) from both A9J1 and A11J3
W22J1 (7) from A12J1
3. Remove the eleven screws (8) and carefully slide the A12 controller (9) out of the module .
Do not damage any of the feedthroughs on the A9 2nd converter PLL or A11 last converter.
T o Replace the A12 Controller
1. Slide the A12 controller (9) into the module . Do not damage any of the feedthroughs on the
A9 2nd converter PLL or A11 last converter.
2. Reconnect the following cables:
W22J1 (7) to A12J1
W5 (6) to both A9J1 and A11J3
W13 (5) to A12J4 and A11J7
W6 (4) to both A9J2 and A12J3
W2 (3) to A12J2
A14 front panel board ribbon-cable (2) to A12J6
W1 (1) to A12J7
3. Replace the module cover . (Refer to the \Module Cover " procedure .)
Figure 9-24. A12 Controller Removal/Replacement
9-38 Replacing Major Assemblies