TRANSFORMER MAINTENANCE

TM 9-4120-430-14

0030 00

UNIT MAINTENANCE

AIR CONDITIONER, COMPACT, HORIZONTAL

TRANSFORMER MAINTENANCE

REMOVAL, TEST, AND INSTALLATION

INITIAL SETUP:

Tools and Special Tools

Tool Kit, General Mechanics (Item 1, Table 2, WP 0067 00)

Test Equipment

Multimeter

Variable voltage power source (AC/DC)

Materials/Parts

Solder (Item 2, WP 0069 00)

Flux (Item 15, WP 0069 00)

References

Wire List and Schematic Diagram (WP 0038 00)

Personnel Required

One

Equipment Condition

Power disconnected from unit

Top covers removed (WP 0018 00)

Junction box partially removed from unit (WP 0028 00)

WARNING

Ensure power source is disconnected.

REMOVAL

1. Remove two screws (1) and two lock nuts (2) to remove transformer (3) from junction box chassis (4). See figure 2.

2. Verify labels to wire list and schematic diagram (WP 0038 00) and disconnect transformer leads (1/4 in. quick

connects).

3. Lift transformer (3) out of unit.

TEST

1. Using a multimeter set on lowest OHMS scale, check for continuity across primary terminals COMN and (208 Vac).

Continuity should be indicated. See figure 1.

2. Using a multimeter set on lowest OHMS scale, check for continuity across secondary terminals (24 volts).

Continuity should be indicated.

3. Using a multimeter set on lowest OHMS scale, check for continuity between primary (208 Vac) and secondary (24

Vac) coils. Multimeter should read NO continuity.

4. If transformer fails steps 1, 2, or 3, transformer is defective. Replace transformer.

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