8-38
Troubleshooting
Portable
PLUS
Computer
8.4
Burning
an
EPROM
Use the following procedure to prepare a 27C64 configuration EPROM (AI U30) before installing it in
the system. This procedure requests the serial
number
of the unit,
and
then
burns
the entire EPROM
memory.
A
new
EPROM must be
burned
and
installed whenever the original is
bad
.
1. Turn off the computer (press
00
in the main
PAM
screen or remove power).
2.
Install the diagnostic module in the left receptacle (receptacle
2,
under
the
ill)
key-see
figure 8-
5).
3.
Ensure that a "
good'
EPROM (AIU30)
is
present
in
the memory PCA. A "good' EPROM is
one
that
functions properly,
but
which
may
not
have
the proper serial
number
stored internally (such
as the original one if it still functions, or a
'dummy'
EPROM-part
number
45711-60925).
This
is
/Jot
the EPROM that will
be
burned-it
merely allows the system to operate.
4.
Connect a good
HP
9114 Disc Drive using two good HP-IL cables.
5.
Turn
on
the disc drive,
then
connect a recharger to the
computer-it
isn't necessary to connect the
battery.
If
the
computer
doesn't
turn
on, press @ or any other key to
turn
it
on
.
If
the oscillo-
scope
menu
appears, go to the next step.
Note:
If
the system
isn't
able to
turn
on
properly, press the reset button
on
the
motherboard
PCA.
6.
Exit from the oscilloscope menu by pressing ( Shift )00.
7.
Configure the computer for one disc drive. Press
(ill
(System Con
fig)
in the main
PAM
screen.
Use the tab or cursor keys to select the "External disc drives' field, then use the "Next Choice"
and
"Previous Choice' function keys to select one drive. Use the "Exit Con fig' function key
to
return
to
the
main
PAM
screen.
8.
Insert
the
service disc
in
the disc drive.
9.
Load
and
run
the
disc-based EPROM-burning program. Type
elburn
(Retum)
or else select
"Burn P + EPROM' from the menu.
10.
Turn
on
a 25-Vdc power supply
and
adjust
it
to 24.8 to 30 Vdc.
11.
Connect
the
25V power supply to the red
and
black wires at the two-pin power connector
on
the
extension
of
the module:
RED
(+25
Vdc)
and
BLACK
(Ground
and
Common, if present). (For a
new
module, first trim the insulation from
the
ends of the wires.) (See figure 8-5.)
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