HP Integral Personal Computer Service Manual page 101

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,..... 84. Po ..... SUppl, VerItIutlon (Coldinuedt
Step
I. If the power supply functions eottectly by
itself, but you still have a tum-on problem,
the voltages may be affected by the other
circuitry of the computer. For example, there
may be a short circuit or
an
excessive load
on a component. To isolate the problem, re-
connect the circuits to the power supply
following steps 9 through 16.
In tach of
these steps, always turn off the power before
you connect or disconnect a cable, or replace a
component.
I. 'fum off the
power.
Reconnect the power-
cable harness to the logic A PCA (leave the
power supply test tool connected).
f
o.
Turn on the power and measure the volt-
ages on the test tool as in step 7 above.
f f.
Disconnect, each in turn, the following
components from the logic A PCA: the key-
board, the I/O backplane PCA, and the
keyboard-connector assembly. After remov-
ing each component, turn on the power and
measure the voltages on the test tool
as
in
step 7.
J
1Ie.ltlngAction
If the voltages are all within specification, go to
step 13.
If any of the voltages are out of specification, or
if the fuse blows, the problem is on the logic
A
peA, the keyboard assembly, the I/O backplane
PCA, the keyboard-connector assembly, or the
ROM assembly. Proceed with step 11.
If the voltages are in specification after one of
the components is disconnected, troubleshoot or
replace that component (or its corresponding
cable).
If the voltages are still not within specification,
or if the fuse blows, go on to step 12.