Table of Contents
Advertisement
HP 3242lA Series III Power Supplies
9-37. Dc Enable
The DeE signal is the same
control
line
connected
to
the
HP
30310A DCE terminal.
It turns on (DCE at gnd) and turns off (DCE
approximately +lOV) the +5V output of the HP 303l2A.
The inter-
face board receives the
DCE signal and generates the appropriate
signal to the
Al control terminal
on the
62605M
Power SUpply.
The interface
board circuits delay the
turnoff of the
+5V line
after release of the
DCE
signal by about
0.15 second
to allow
ample time
for the
HP 303l0A
Power Supply to generate
its PFW
signal for the
cpu.
This delay guarantees the +5V output will be
present for at least 1.0 msec after the CPU rece ives the
PEW
s ig-
nal.
9-38. HP 30312A SERVICING INFORMATION
WARNING
While the input
power
is
connected,
use
caution
when working inside the power sup-
ply.
Many exposed conductors carry low
dc
voltages
which
are
capable
of supplying
heavy currents if shortcircuited, resulting
in high heat and the possibility of painful
burns.
Use caution when manipulating metal
tools or probes.
A wrist watch, or a metal
necklace, bracelet, or
ring
must
not
be
worn.
Avoid
dropping
tools, screws, or
other metal objects onto
conductors.
Re-
move
power
and recover dropped obj ects at
once; if
forgotten,
damage
could
result
later.
Ac power line
voltage is
exposed
when covers are removed.
Exercise
extreme
caution
when
working
in the power supply
with covers removed, and never
work
under
this
condition
unless
another
person is
nearby and within sight.
The
HP
303l2A Power Supply is a nonrepairable unit and,
if found
defective,
it must
be replaced.
Except for replacing
an open
fuse or the interface board
(30312-60002),
no repair procedures
are required.
If the computer system is down because the 5-volt
output of
this power
supply is absent,
disconnect the
wire at
terminal Al of the HP 62605M Power Supply.
If power is restored,
the interface board is defective.
If power is not restored,
the
HP 62605M unit is defective.
9-24
Advertisement
Chapters
Table of Contents
Troubleshooting
