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NOTE
1
f
The
Signature
Analyzer
Controls
Should Be
Set
Follows
For
This
Test:
LINE
ON
(IN)
START.
"V
(IN)
STOP
y(OUT)
CLOCK.
J~(OUT)
HOLD
OFF
(OUT)
SELFTEST
OFF(OUT)
NOTE
2
The Following
Is
A
List
Of Components
Which Are Connected
To The Output
Data
Bus.
Schematic 8
Schematics
Schematic 10
AiU23
AWiI
AWSi
A1U24
AWI8
AW54
AW25
AW19
AiU63
AW29
A1U20
AW64
AIU3I
A1U26
AiU65
A1U34
AIU66
A1U3S
A1U67
A1U36
AiU6S
AW37
AIU69
A1U42
AW70
A1U43
Start
Be
Certain
That
The
Test
Jumper
On
The
A3
Assem-
bly
Is
Disconnected,
The
Plug
Is
Disconnected
From
A1J7
And
All
HP-18
Address Switches Are Set
To The
"9"
Position.
Torn
Instrument
ON.
I
Connect
The
Signature
Analyzer
START
and
STOP
Inputs
To
A3TP1.
Connect
The
CLOCK
Input
To A3TP5 And
The
GNO
To
The
Chassis.
(See
NOTE
1
For
Signature
Analyzer Control
Settings,)
I
Use
The
Signature
Anal-
I
zer
To
Check
The
RAM
Output
Signatures
At The
Following
Points:
Location
Signature
A1U34
Pin
2
184P
Pins
7FPH
Pin
9
AFOP
Pin
12
UHUC
A1U42
Pin
2
P6PH
Pin
5
P961
Pin
9
PH16
Pin
12
8CPA
The
RAM
Circuits
Are
Operating Cor-
rectly.
i
Go
To
The
ALU
Trouble-
shooting Procedure.
3455
-
8-20
1
Check The
Signatures
At
The
Following
Points:
Location
Signature
:
A1U44
Pin
9
AFOP
Pin
10
184P
Pin 11
UHUC
Pin
12
7FPH
A1
U45
Pin
9
PH16
Pin
10
8CPA
Pin 11
P961
Pin
12
P6PH
Go
To
The
Device
Select
Troubleshooting
Proced-
ure.
Turn
The
Instrument
OFF
And
Carefully
Remove
A1U44
And
U45.
Turn
The
Instrument
ON,
Output
Buffer
A1U35
Or
AIU43.
I
Check The
Signatures
At
The
Following
Points:
Location
Signature
A1U44
Socket
Pin
1
93AF
Pin
2
U6FF
Pin
3
OHAH
Pin
4
AACA
Pin
5
1UFP
Pine
FF11
Pin 7
671
F
Pin
16
143A
Go To
The
Device
Select
Troubleshooting
Proced-
ure.
1
Turn
The
Instrument
OFF.
Connect
A
10
kO
Resistor
Between The
-t-B
V
Test
Point
On
The A1
Assembly
Artd
The
Probe Tip Of
The
Signature
Analyzer
Turn
The
Instrument
ON.
i
'
Check
The
Signatures
At
The
Following
Points:
Location
Signature
A1U44
Socket
Pin
9
7078
Pin
10
97C6
Pin 11
F757
Pin
12
15FU
A1U46
Socket
Pin
9
62PP
Pin
10
P2F8
Pin 11
H3FH
Pin
12
3A9C
Presettable
Counter
A1U36
Or U37.
Data Bus
Output
Buffers
A1U34
or
U42.
A
Signature
Of 0
0 0
0
Indicates
The
Output
Data
Bus
Line
Is
Being
Held
Low.
Troubleshoot
The
Components
Which
Are
Connected
To
This
Line,
(Sea
Note
2.)
In
Most
Cases,
A
High
Resolution
Voltmeter
(1
pV
Resolution)
May
Be
Used
To
Determine
The
Bed
Component.
In
Gen-
erel.
The Component
Hold-
ing
The
Line
Low
Will
Have
The
Lowest
Voltage
Reeding.
When
Trouble-
shooting
The
Data
Bus,
The
A3
Assembly
Should
Be
Removed
From
The
Instrument.
NOTE
3
Be
Sure
To
Remove
The
10
Resistor
Connected
Between
The
Signature
Analyzer Probe
Tip
And
The +S
V
Test
Point.
Replace
A
1U44
And A
1
U4S.
Figure 8-H-22.
Outguard
Troubleshooting Procedure
Diagram,
RAM
Circuitry.
8-123/8-124
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