TM 11-6625-3087-12
APPENDIX B
MAINTENANCE ALLOCATION CHART (MAC)
Table 3. Remarks for Frequency Selective Level Meter, AN/USM-490
REMARKS
CODE
REMARKS
1
Visual inspection of all external surfaces only.
2
Normal operational test.
3
Replacement of fuses, knobs, and any other maintenance on the external surface of the
AN/USM-490.
4
Visual inspection of all internal and external areas.
5
Fault isolate to piece parts. Circuit cards tested as part of end item.
6
All mechanical and/or electrical adjustments need to return the AN/USM-490 to
operational status.
7
Governed by TM-43-180 and the associated TB.
8
The following are repaired by replacement circuit card assemblies: A31, A32, A51,
A52, A53, A61, A62, A80, and cable assemblies W1, W3-W15, W17 and W18.
9
To be returned to the depot only in the event that TSG is unable to repair the AN/USM-
490 either due to a lack of parts or time factor.
10
Some procedures require the use of 75 ohm coaxial cables.
11
Tool number 5, circuit card extender kit, consists of the following:
A. 44 pin extender board (2 each) PN 03586-66590
B. 30 pin extender board (2 each) PN 03586-66591
Change 1 B-7(B-8 Blank)
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