Chapter 7 147
Troubleshooting the Processor, Power Supply, and Display
A25 Motherboard Description
A25 Motherboard Description
Purpose. The A25 Motherboard provides the following functions:
• Provides a load to the power supply assembly for the +9 V, −5.2 V,
−15 V, +5.2 V supply lines. This allows a minimum set of PC board
assemblies to be present for power supply operation. See the power
supply troubleshooting section of this manual for a list of minimum
assemblies required. This will help isolate power supply problems.
• Provides regulated +12 V and −12 V supplies to the CPU assembly.
• Provides interconnections between many assemblies.
• Location of the on/off switch.