TRANSFORMER, RECTIFIER, CAPACITORS, AND

TM5-4120-384-14

4 - 3 1 . TRANSFORMER, RECTIFIER, CAPACITORS, AND

(7) Inspect electrical parts for obvious damage such

cracks, evidence of overheating, and broken terminals.

(8)

Replace

all

damaged

broken

parts.

Test.

(1)

Transformer

T1.

Do not remove jumper between

(a) Tag and disconnect leads.

pins 3 and 4 on transformer.

Check for continuity across the

primary winding pin 2 to pin 5 (on models F18H-3S, F18H-3SA and

F18H-3SB) or access pins 1 and 6 on model F18H-1S and across the

If either winding is open,

secondary winding pin 7 to pin 8.

replace transformer.

(b) Check for shorts between one terminal of each winding

and transformer case and also between one primary terminal and one

secondary terminal using an insulation tester, megger or multimeter

Replace transformer if a short is indicated.

on high ohms setting.

Voltage at

volts AC to terminals 2 and 5 (input terminals).

Remove

transformer terminals 7 and 8 should be 27 to 33 volts AC.

Replace defective transformer.

power from transformer.

Apply 230 volts AC to terminals 1

(d) (On model F18H-1S)

Voltages at transformer terminals 7 and 8

and 6 (input terminals).

Remove power from transformer.

should be 27 to 33 volts AC.

Replace defective transformer.

(2)

Rectifier

CR1.

(a)

Tag

and

disconnect

leads.

(b) Using a multimeter on high ohms setting connect

negative (-) lead to terminal 2 and positive (+) lead to terminal

A low resistance reading should be obtained.

or 3.

and negative lead

A very high resistance or

open circuit reading

to terminal 1 or 3.

should be obtained.

(d) Connect positive lead to terminal 4 and negative lead

A low resistance reading should be obtained.

terminal 1 or 3.

(e) Connect negative

lead

to terminal 4 and positive lead

A very

high

resistance or open circuit reading

to terminal 1 or 3.

should be obtained.

(f)

Replace

defective

rectifier.

4-89

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