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Service
8-8-34. Unless otherwised
troubleshooting
information
paragraphs are used in conjunction with Schematic 8.
Also, the common ground used is ground 114.
8·8·35. Pra·TroubleshDoting Information.
8-8-36. Before troubleshooting the Inguard Logic,
check for the following:
a. Make sure the + 5 V Power Supply is good
(A30U l 3 pin 40).
b. Check and make sure pins 2 and 3 of U l 3 have a
5.85 MHz (60 Hz Option) or 4.875 MHz (50 Hz Option)
Clock Signal. If they are not present, troubleshoot the
clock circuitry. Do the following:
I .
Check for a clock signal (5.85 MHz for the 60 Hz
Option or 4.875 MHz for the 50 Hz Option) at
A30TP3. If the signal is not present, replace Y I ,
Q I . o r V12.
2.
If the signal is present. replace U12.
c. Make sure the RESET Line of the processor
(A30UI3) is good. The line can be checked by doing the
following:
I .
Using a logic probe, monitor pin 4 of A30U l 3 .
The line should be high.
Paragraph 8-8-39 for troubleshooting.
is high, continue with the next step.
2.
Using a logic pulser, toggle pin 40 of A4U I 5
(momentarily short pin
Schematic 9, to ground).
3 .
The RESET line of the Inguard Processor
tr
(A30U 1 3 pin 4) should go from high to low to
high.
this does not happen, go to Paragraph
8-8-39 for troubleshooting.
RESET line is good. (Note: The
may continue toggling for certain Inguard
failures.)
d. Check the ROM of the processor (A30UI3). Do
the following:
I .
Turn the 3456A Off.
2.
Unplug the cable from the Isolation Logic Con
nector (A3U7, Schematic 12).
3 .
Move A30J35 and 136 t o the Non-Run (2 and 3 )
position.
4.
Turn the 3456A On.
5 .
Using a logic probe. monitor U I 3 pin 8. With the
3456A's Front/Rear Switch in the FRONT posi
tion. pin 8 should be high. With the switch in the
REAR position, the pin should toggle. Replace
U 13, if other conditions are noted. (Note: Make
sure the Front/Rear Switch is good, before
replacing VI3.)
e. Check and make sure pin 1 1 of A30U 1 3 is tog
gling. I f it is not toggling, replace A30U13.
8-8-10
noted,
all checks and
in
the
following
t r
tr
the line i s low, go to
the line
40
o f U 1 5 , shown on
RlsE4'
tr
it i
the
line
r.
Check and make sure pin 9 of A30U6 is oscillating.
tr not oscillating, do the following:
I .
Make sure pin 10 of U I 2 is oscillating. If not
oscillating, replace U12.
2.
Make sure pin 8 of U5 is oscillating. If not
tr
oscillating, make sure pin 1 2 of US is oscillating
(or high).
wrong, replace U6. If the pin is
good, replace U5.
3.
If pin 8 of U5 is oscillating, replace V6.
8·8·37. R.nge .nd Ingu.rd logic failura.
8-8-38. To troubleshoot for a Range or Inguard Logic
Failure, do the following:
a. Turn the 3456A Ofr.
b. Make sure the Front/Rear Switch of the instru
ment is in the FRONT position.
c. Make sure the cable from the Isolation Logic Con
nector (A3J7) is unplugged (Schematic 12).
d. Move A30J33/J34 to the "2" (middle) position,
as shown in Figure 8-8-2.
e. Move A30J35 and 136 to the Non-Run (2 and 3)
position.
r.
Connect (to A30 Assembly) and set the Signature
Analyzer as follows:
Start:
A30J31 -STR
Stop:
A30J31-STP
Clock:
A30J32-A
Gnd:
A30J31-GND
Hold:
Self-Test:
g. Using the SA probe. take the following signatures
and check for the correct condition of the probe (Off,
On. or Toggling). Check the following:
SA Connedion
A30P21
Pin 1 (F/R)
Pin 6 (PROG)
Pin 7 (LMES)
Pin 8 (LGND)
A30P30
Pin 4 (TRIG)
Pin 5 (ALE)
Pin 6 (LRU)
Pin 7 (HSA)
Pin 8 (HSq
Pin 9 (HS8)
Pin J O ( + 5V)
h. If any signatures or the condition of the SA Probe
are wrong, continue with the next step. I f the signatures
are good. go to step j .
i. Do the following:
I .
Turn the 3456A Ofr.
Model 3456A
.r )
(
'-
( .r
(
)
)
OUI
Oul
P
r
e
l
ob
Sla
e
Off
On
7F0 4
Toggling
9A76
Toggling
ODFO
Toggling
0000
Toggling
Toggling
6578
P242
Toggling
3718
Toggling
Toggling
4661
ODFO
On
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