TM9-4120-401-14
4 - 3 9 . TRANSFORMER (T1). - continued
b. Test.
(1) Tag and unsolder wire leads. (See paragraph 4-24.)
(2) Remove four screws (2), bck washers (3), flat washers (4), and transformer (1).
(3) Using a multimeter, check continuity across the input winding pins 1 and 2 and across the output
winding pins 3 and 4. If either winding shows open (no continuity), replace transformer.
(4) Check for shorts between one terminal of each winding and transformer case and also between one
input terminal and one output terminal using an insulation tester, megohmeter or multimeter on high
ohms setting. Replace transformer if a short is indicated.
(5) Apply 208.020.8 volts AC to input terminals 1 and 2. Voltage at transformer output terminals 3 and 4
should be 23.50.7 volts AC. Remove power from transformer. Replace if defective.
(6) Secure transformer (1) to unit with four screws (2), bck washers (3), and flat washers (4).
(7) Solder wire leads to transformer (1) terminals using tags and wiring diagram (figure 4-6). Remove tags.
(See paragraph 4-24.)
c. Replace.
(1) Tag and unsolder wire leads. (See paragraph 4-24.)
(2) Remove four screws (2), bck washers (3), flat washers (4), and transformer (1).
(3) Secure new transformer (1) to unit with four screws (2), lock washers (3), and flat washers (4).
(4) Solder wire leads to transformer (1) terminals using tags and wiring diagram (figure 4-6). Remove tags.
(See paragraph 4-24.)
NOTE
FOLLOW-ON MAINTENANCE:
Install return air buver and air filter (para 4-18).
Connect power at power source.
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