TM 55-4920-428-13
4-31. Replacement of Undervoltage Detector/Precision Rectifier
a.
b.
c.
d.
e.
f.
g.
h.
i.
Circuit Board TB6B. (CRC)
Remove the panel (para 4-18).
Remove the screws securing the circuit board (19) to the spacers (fig. 6-3).
Tag and unsolder the wires from the circuit board.
Solder the wires to the replacement circuit board. Use solder QQ-S-571 (wiring diagram, FO-21).
Remove the tags.
Align the circuit board mounting holes with the spacers. Secure the circuit board with screws.
Perform the power supply and DVM tests (para 4-40) (Adj. para 4-35).
Install the panel (para 4-41).
Perform the final test (para 4-42).
4-32. Replacement of Transformer T1. (CRC)
a. Remove the panel (para 4-18).
b. Tag and unsolder the wires from the transformer (11) (fig. 6-3).
c. Remove the attaching hardware. Remove the transformer.
d. Install the replacement transformer. Secure it with the hardware.
e. Solder the wires to the transformer. Use solder QQ-S-571 (wiring diagram, FO-21).
f. Remove the tags.
g. Perform the power supply and DVM tests (para 4-40).
h. Install the panel (para 4-41).
i. Perform the final test (para 4-42).
4-33. Replacement of Power Supplies PS1, PS2, and PS3. (CRC)
a. Remove the panel (para 4-18).
b. Tag and unsolder the wires from the power supply (5, 7, or 32) (fig, 6-3).
c. Remove the attaching hardware. Remove the power supply.
d. Install the replacement power supply. Secure it with the hardware.
e. Solder the wires to the power supply. Use solder QQ-S-571 (wiring diagram, FO-21).
f. Remove the tags,
g. Perform the power supply and DVM tests (para 4-40).
h. Install the panel (para 4-41).
i. Perform the final test (para 4-42).
Change 3
4-9
