Philips pm2521 - Page 174

2
5.
SETTINGS AND
CONNECTION OF
THE SIGNATURE
ANALYSER.
!
SETTING
SIGNATURE
ANALYSER
CONNECTION
SIGNATURE
ANALYSER
NAME
EDGE
NAME
TESTPOINT
SIGNAL
NAME
START
“L
(neg)
START
TP 14
pTtI (D1904
pin
34)
STOP
(pos)
STOP
TP
14 P17I
(D1904
pin
34)
CLOCK
J~
(pos)
CLOCK
TP
15
ALE {D1911 pin
11)
GROUND
—
GROUND
TP 1
Logic
0
(neg)
D1903
pin 7
AZC/P
QUALIFIER
QUALIFIER
-
iT
(pos)
D1903
pin
2
AZ
NOTE: 1.
The qualifier is
only necessary
for test 3
and 5.
2. The
testrom must
be
placed
in
the D 1909
socket.
6.
BRIEF
DESCRIPTION
OF THE
TESTS
Free
run test
With this
test it is
possible te
measure
signatures on the
address
latches
and the
databus of
the processor.
This is
necessary to check
if the data can
be taken
from the
testrom.
Test
0
(ram
and
I/O
test)
This
test
checks the
internal RAM of
the
microcomputer.
When the RAM is
good it
will also test the I/O
ports
of the
microcomputer.
Only
then
can signatures
be
measured
on
the I/O ports,
databus
and ROMs.
It also
activates the
connections
of the L.C.D.
unit.
Test
1
(visual L.C.D.
test, no S.A.)
The test
fills the
display, segment
after segment.
When a
connection
to
a
segment is
broken, that
segment
will not light.
When two
connections
are short
circuit, then
two segments
will be lit
simultaneously.
In this test
signature
analysis is not
provided.
Test
2
(switch
decoding test)
Test 2 activates
the circuit
necessary
for reading the
function switch,
and the
+/—
,
AUTO,
DOWN,
UP,
10 Amp.
input bus,
and the
battery low input.
Signatures
can be
measured on IC's D1912, D1916,
D1919
and on I/O
port 2.
(P20' P21
' P22'
P23'and[P^
)-
The signatures on|P25|
depends
on
the position of the
function
switch and keys,
pressed or
not
pressed.
Test
3
(relay
/fet switch test)
This test
activates the circuit
for relay/fet switch
control.
Signatures
can be
measured on the inputs of D1908,
and the
outputs driving the
relays.
The outputs
of D1908 are
activated
sequentially.
Outputs driving
the fet's
will give stable signatures,
but with
an oscilloscope it is
also
possible to see
if
the
fet's are switching.
Test 4
(static
relay/fet
switch
test, no S.A.)
This
test is
not
intended for
signature analysis.
It
sets
the relay
/fet's in
the
state, according
to
the
selected
function
and range. It
can
also
change
the
internal program
status.
With
the
button
+/-,
the
polarity
can be
changed
if the V-,
Att.,
or the
function
trigger
level is
selected.
With
the
button
AUTO/MAN*,
the
internal
program
status
can
be changed,
(normal
measurements,
AUTOCAL
0,1V
or IV,
IZERO
200mA
or 2A).
So
it is
possible to
make
measurements in
the analog
part
of the PM2521
.