Halt
Code
Test
Area
Tested
Service
Aids
Undefinable Resets all
I/O
devices. Resets
A2, B2, E2,
F2,
G2,
Probe -POR on the
F2
card while
/'
current machine checks and H2,
J2
activating bring up.
',--,
enables parity checking.
Puts
AAAA
in
R3LO.
This halt G2, H2 Use the DISPLAY REGISTERS
code remains in
R3LO
to
the switch
to
check
R3LO.
end
of
the bring up diagnostic.
Tests
read/write
storage
G2,
K2 Use the DISPLAY REGISTERS
/F
---,,\
locations 0020 through 05FF. switch
to
check
RFLO.
If
RFLO
is
~
less than 0080, replace J2.
Blank Resets the CRT buffer on
J2 J2
Use the DISPLAY REGISTERS
card
to
all blanks. switch
to
check
for
a blank display.
The display screen should
be
blank
/"
-'\
in normal mode only.
A Turns all bus
in
bits on. A2*,
F2,
G2,
H2
Probe the 'bus in' lines on the
F2
card. All bus
in
bits should be up
or pulsing.
AB Tests processor G2 Probe the 'RDR error' line on the
microinstructons.
G2 card. Loop on the op code test
in
DCP
if
the problem is
intermittent.
ABC Tests the ability
to
switch
to
F2,
G2,
H2 None.
read/write
storage and back
to
ROS.
ABCD Activates program interrupt A2,
B2,
F2,
all
I/O
Level 1 - B2
"',
levels
1,
2,
and 3. Level 2 - A2,
F2,
tape control card,
./
5106, and 5103
Level 3 -
F2
or
keyboard
ABCDE' Tests all device addresses.
0-
G2 Probe the device address error on
1 -
E2
the device.
4 -
F2,
Kbd
5 - 5103
8 - B2
E -
F2,
tape drive,
5106
ABCDEF'
Tests bus
out
parity. A2,
B2,
E2,
F2,
G2, Remove A2,
B2,
and
E2.
Reinstall
all
I/O
them one at a time. The card that
causes
ABCDEF on
POWER
ON should
/
be
replaced.
If
this does not fix
the problem, the cause might
be
F2
or
G2.
*Not
tested by the bring up diagnostic but can cause bring up halts.
'Interrupt
errors can occur during bring
up
diagnostics ABCDE through ABCDEFGHI
(see
ABCD
for
levels).
3-14
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