METER FUNCTION SWITCH AT REGULATED DC: LOW OR HIGH READING ON TEST METER

TM 11-5805-387-34-2

MALFUNCTION/SYMPTOM

PROBABLE CAUSE

TEST PROCEDURE

INDICATION

YES

(4) METER FUNCTION SWITCH AT

Defective: Circuit board A9, Series regulator

REGULATED DC: LOW OR HIGH

Transistors Q1, Q2, Q3

READING ON TEST METER

NOTE

Series regulators Q1, Q2, Q3 automatically cut off when the +22 volt dc output of preregulator

board A9 is shorted. Normal operation will resume when short is removed.

1. Connect ME-26BIU across junction of L1

+22 vdc

Go to 2.

Replace

and C22; measure voltage.

1.0

defective

board A9

2. Connect ME-26B/U between terminals (E35

+1 to 5 vdc

----------

Go to 3.

and E37) of resistor R8; measure voltage.

3. If voltage less than 1 vdc, check series

Short

Replace

Go to 4.

regulator transistors Q1, Q2, Q3 for shorts.

defective

transistor

4. If voltage greater than 5 vdc, check series

Open

Replace

----------------

regulator transistors Q1, Q2, Q3 for open

defective

condition.

transistor

2-12