156 Chapter 7
Troubleshooting the Processor, Power Supply, and Display
Isolating an A5 Power Supply Problem
Remove these assemblies first
(refer to Chapter 11 for removal instructions):
• A11 Reference assembly
• A12 Synthesizer assembly
• A10 Third Converter assembly
• A7 Digital IF assembly
• A9 Second Converter assembly
• A8 Analog IF assembly
Other assemblies to remove include:
• A13 Front End Driver - the front end driver supplies voltages to the
RF section assemblies and the input attenuators. Therefore, if the
problem goes away upon removing the front end driver, suspect any
of the assemblies it provides voltages to.
•A6 SCSI
• A2 Front Panel Interface assembly - (disconnect the ribbon cable)
• A23 Floppy Disk Drive
The Minimum Assemblies required to power up the instrument are:
• A25 Motherboard
• A5 Power Supply assembly
• A26 CPU assembly