Compaq 420CX 486 DX4/75 MHZ 420 MB 8 MB 10.4 Personal Computer User Manual


 
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Battery contacts Remove the keyboard
not making good assembly and examine the
contact with battery contacts. Ensure
battery. that the battery is making
good contact with all 4
contacts.
Replace the system board.
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Defective system Replace the system board.
board.
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Problem Probable Cause Solution(s)
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The computer has a Short circuit on 1. Remove the following
crowbar condition: it one of the power parts one at a time
powers up for a short supply outputs. until the short circuit
period, then shuts off. is located:
indicators flash on,
then off (this takes NOTE: After verifying
place in less than 3 that a part is not the
seconds). cause of the short
circuit, reinstall it
before removing the next
part. In addition, note
that the first three
parts can be checked by
the user.
a. PC card
b. Battery pack
c. Hard drive
d. Diskette drive
e. Internal AC power
supply
2. Disconnect the display
cable from the system
board and power the
unit up. If the unit
powers up, the display
cable or display
assembly has failed.
Plug the display cable
back into the system
board and attempt to
find the defective
part in the display
assembly by completing
the following steps
one at a time until
the short circuit is
located:
a. Disconnect the
display cable from
the inverter board