ARMY TM 9-6115-464-34
AIR FORCE TO 35C2-3-445-2
NAVY NAVFAC P-8-624-34
d. Testing and Repair.
NOTE
Disconnect leads to components prior to testing to avoid erroneous readings.
(1) Test individual components using figure 3-66 as a guide and perform the following steps:
(a) Using a VOM, check for continuity between the following test points of transformer T1, figure 3-66:
TP1 and TP2, TP8 and TP9, TP15 and TP16, TP5 and TP6, TP6 and TP7, TP5 and TP7, TP12
and TP13, TP13 and TP14, TP12 and TP14, TP19 and TP20, TP20 and TP21, and TP19 and
TP21.
(b) If continuity is not indicated in all of the above checks and open circuit exists in the transformer
windings, replace transformer (25, figure 3-64).
NOTE
Continuity of secondary windings of transformer T1 can be checked by using pins K
and A, L and B, and M and C of plug P7 if desired. This method could show continuity
if the connector P7 is faulty, even though the transformer has an open winding.
(c) Using a VOM, check for open circuit indications (infinity) between the following test points of
transformer T1, figure 4-13; TP1 and TP5, TP1 and TP6, TP1 and TP7, TP2 and TP5, TP2 and
TP6, TP2 and TP7, TP8 and TP12, TP8 and TP13, TP8 and TP14, TP9 and TP12, TP9 and TP13,
TP9 and TP14, TP15 and TP19, TP15 and TP20, TP15 and TP21, TP16 and TP19, TP16 and
TP20,TP16 and TP21, TP7 and TP12,TP14 and TP19, TP2 and TP8, TP9 and TP15.
(d) If continuity is indicated in any of the above checks, replace the transformer (25, figure 3-64).
(e) Using a VOM, check diodes (1 through 6, figure 3-66). Check diode CR1 by placing the positive
probe of the VOM on TP3 and the negative probe on TP5. The VOM should indicate continuity.
Reverse the probes: the VOM should indicate open circuit. If the diode fails either of these tests,
replace the diode (26, figure 3-64).
(f) Check the remaining diodes, CR2 through CR6 using the same procedure. Replace any diodes
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
found to be defective.
Install load measuring unit in the test circuit shown in figure 3-67.
Remove load measuring unit cover.
Adjust load bank R1 so that it will apply no load to power source G1.
Activate power source and adjust to obtain a reading of 208 Vac on voltmeter M1.
Adjust load measuring unit load resistor (17, figure 3-64) to obtain a reading of 0.0 to 0.4 Vdc on
voltmeter M2 (figure 3-67).
Place load bank on the line and check reading of voltmeters M2 and M3. Readings shall be 9.6 ± 0.2
Vdc and 5.4 Vac respectively.
Slowly adjust load bank from zero to full load while observing voltmeter M2 and M3. Indication of
voltmeter M2 shall vary from 0.0 to 9.6 ± 0.2 Vdc as indication of voltmeter M3 varies from 0.2 ± 0.2
to 5.6 Vac (figure 3-67).
If necessary, adjust load measuring unit load resistor (17, figure 3-64) to obtain the relationship
shown in figure 3-67.
3-155
