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Model l l l 80A
Section V
SECTION V
MAINTENANCE
5-1. INTRODUCTION.
5-2. This section contains information for incoming inspec-
tion and troubleshooting of the l l l
80A.
No adjustments or
calibration is necessary for the l l l
80A.
5-3. EQUIPMENT REQUIRED.
5-4. The following equipment is required to check the
performance of the l l l 80A:
3480A/B Digital Voltmeter
3481
A,
3482A, 3484A or 3485A plug-in unit
5050B
or
5055A Digital Recorder
Oscilloscope, general purpose
5-5. PERFORMANCE CHECKS.
5-6. To check the performance of the
l l l
80A for incom-
ing
inspection,
it is recommended that the minimum checks
to be made are the Data output on IBCD and Storage
modes; and Limits, Preset Triggers and Scanner operation
(if a 3485A is available) on the Storage mode (Storage
Enable line held low).
5-7. IBCD Check.
5-8. In this
check,
the Storage Enable line is left open to
allow the
l l l
80A to operate in the Isolated BCD (non-
Storage)
mode.
The Scanner Units l.D., Data, Range (or the
Scanner Tens Channel I.D.), and function (or Scanner
Range) are checked with the Digital Recorder at the
l l l
80A Storage Connector shown on Page 3-1. See the
BCD OUTPUT CHECK in the 3480A/B Manual.
5-9. Storage Check.
5-10. In this check the Storage Enable line is grounded to
allow Storage mode of operation. The Storage Units I.D.,
Data, Range (or Scanner Tens channel I.D.), Function (or
Scanner Range), and the Storage Tens Channel 1.D. are
checked with the Digital Recorder at the
l l l
80A Storage
Connector shown on Page 3-1.
5-11. Basic Operation. Refer to Paragraph 3-6 and Figure
3-2 for basic operation with a digital recorder. Exercise all
of the Storage Limit lines to insure that the
l l l
80A will
store and output 10, 20,
30,
40 and 50 readings. Check the
Storage and Status Flags with the
oscilloscope.
5-12. Preset Trigger Operation. Refer to Paragraph 3-9 and
Figure 3-5 for Preset Trigger Operation. Use a slow trigger
rate so that the input voltage to the 3480 may be changed
at the time a Preset Trigger line is grounded. This allows the
"X" readings that occur before Preset Trigger to be
distinguished from the
"Y"
readings occuring after Preset
Trigger. Exercise all three of the Preset Trigger
lines.
5-13. Scanner Operation. Refer to
Paragraphs
3-24 and
3-25 for operation with the 3485A Scanner. The Scanner
Enable line as well as the Storage Enable line must be
grounded.
5-14. TROUBLESHOOTING.
5-15. The Troubleshooting Table 5-1 is an outline of the
circuits to be checked for five major failure symptoms
:
I.
Data Output problem
II.
Isolated BCD control problem
III.
Storage control problem
IV.
Address problem
V.
Scanner-Storage problem
5-16. A Data output problem is related to the circuits on
Figure 7-10; all other problems will occur in the circuits on
Figure 7-9. Decide whether the problem is strictly in the
Data output or in control on the IBCD or Storage
mode.
Other possible problem areas are in the output address and
Scanner-Storage
operation.
These five major problem areas
are further broken down into more particular problem areas
within the Troubleshooting
Table.
Table 5-1. Troubleshooting.
I.
Data Output problem
.
A. Compare the data on IBCD and Storage modes
.
1 . If they both have the same error, check the Data
Outguard Flip-Flop on A2.
a.
*If a datum is always high, then the pulse transf-
ormer
,
coupling capacitor, or flip-flop is bad
.
b.
*If a datum is always low, then the fl ip-flop is bad.
* Note: The D4000 line has the opposite logic sense of
the other data lines.
2
.
If the Data is alright in I BCD mode but has an error in
Storage mode, check the MOS Shift Register and
Memory Transfer Gate on A
1.
3.
If the Data is alright in the Storage mode but has an
error in I BCD mode, check the Present Transfer Gate on
A1.
B.
Front panel readout has an error, but the IBCD is alright
.
1 . Check the Panel Transfer Gate on A 1
.
2. Check the mainframe (3480) Reset, Test Point No. 1, on
03480-66502 assembly
.
5-1
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