Service manual

12
Note: On the Agilent 60504B/07B modules you must first disassemble the heatsink before you can access the
defective subassembly. First remove the three screws that secure the heatsink spacer to the heatsink. Then
completely loosen the ten screws that secure the heatsink to the T-bar. Separate the heatsink from the
T-bar taking care that the heatsink screws don t fall out of the holes. This makes it easier to reassemble the
heatsink.
• Cut all the transistor leads on the defective subassembly close to the transistor bodies and remove the subassembly.
• Unsolder the cut transistor leads from the power board and clean the corresponding mounting holes.
• When replacing the subassembly, be sure to apply heat-conducting grease or a new thermal pad to the back of the
subassembly before reinstalling the heatsink.
Do not use any heatsink compound using silicone which can migrate and foul electrical contacts
elsewhere in the system. An organic zinc oxide cream such as American Oil and Supply Company
Heatsink Compound is recommended.
Transformer (on mainframe)
• Remove the front panel (see Front Panel).
• Record the color code and location of each wire connected to the transformer.
• Disconnect the wires from the transformer.
• Use a short #2 Pozidrive screwdriver to remove the two screws securing the transformer, and remove the transformer
from the unit.