Servicing Rotary Switches - HP 333A Technical Manual

The -hp- Part Number for the assembly is marked on
the circuit board to identify it.
5-43. The etched circuit boards are of the plated-
The electrical connection between the
through type.
two sides of the board is made by a layer of metal
plated through the component hole. When working on
these boards, observe the following rides:
a. Use a low-heat (25 to 30 watts) small-tip sol-
dering iron, and a small diameter rosin core solder.
b. Remove circuit components by placing the sol-
dering iron on the component lead on either side of the
board, and pulling up on the lead. If a component is
obviously damaged, clip leads off as close to the com-
ponent as possible and then remove leads with a sol-
dering iron.
EXCESSIVE HEAT CAN CAUSE THE CIR-
CUIT AND BOARD TO SEPARATE, OR
CAUSE DAMAGE TO THE COMPONENTS.
c. Clean component lead hole by heating the hole
with the iron and inserting a wooden toothpick Re-
move the toothpick after the solder has cooled and
insert the new component lead
d. To replace components, shape new leads and
insert them in lead holes. Reheat with soldering iron
and add a small amount of new solder as required to
insure a good electrical connection.
e. Clean excessive flux from the connection and
adjoining area

5-44. SERVICING ROTARY SWITCHES.

5-45. The 333A/334A has five rotary type switches
FUNCTION, SENSITIVITY, FREQUENCY RANGE,
MODE, and METER RANGE. When working on these
switches, observe the following rules:
a. Use a low-heat (25 to 50 watts) small-tip sol-
dering iron and a small diameter rosin core solder.
b. When replacing components, attempt to dress
them as nearly to their original alignment as possible.
c. Clean excessive flux from the connection and
adjoining area.
d. After cleaning the switch, apply a light coat of
lubriplate to the switch detent balls. DO NOT apply
lubricant to the switch contacts or allow lubricant to
contaminate components.
TM 11-6625-1576-15
Section V
Paragraph 5-43 to 5-45
5-13