Backplane Connector Fault Isolation - Zenith Z-100 PC series Service Manual

Page
4.3
Troubleshooting
If the power supply checked good and one or more of the voltages is
now deficient, the supply is, more than likely, being loaded down by one
of the cards. Remove the cards one at a time until the deficient voltage
returns to normal, then refer to the troubleshooting section for that card.
Backplane Connector Fault Isolation
If you have reason to suspect a defective backplane signal bus connector
of causing a problem, perform the following:
1. Turn off the computer, and swap cards in the suspect location; e.g.,
remove the video card and replace it with the CPU card.
2. Turn the computer back on and perform several operations to deter ­
mine if the problem still is present, or has changed in nature.
If the same problem still is present, it is probable that the cause is on
a card whose function is related to the nature of the problem. Consult
the troubleshooting section for the affected card.
If the nature of the difficulty has changed, try to relate the symptoms
to the particular cards used in a given location to pinpoint the defective
backplane connector.
Once the suspect location has been determined, turn off the computer
and visually inspect the edge connector in that location for physical dam ­
age, poor solder connections, corroded contacts, etc. If no discrepancy
is noted, connector replacement is indicated.