LESSON 2
ISOLATE MALFUNCTIONS AND REMOVE AND REPLACE DEFECTIVE COMPONENTS
Section I. ISOLATE MALFUNCTIONS
2-1.
CIRCUIT DESCRIPTION
In describing the circuit configuration, we will use the parallel method beginning
with the black wire, hot side, and complete the circuit with the neutral (common) side.
Refer to figure 2-1 for the Dynac II schematic.
a. Armature Circuit.
(1) With the power cord plugged into the wall outlet (receptacle), close the
lid. When the cover latch snaps into place, it automatically closes the lid interlock
switch, which is on the neutral side of the line.
NOTE:
Reference is now on common at the power cord side of S-1.
(2) The 120vac will be on the black wire through fuse F-1 to one side of switch
S-1. Close S-1 and continue on the white/tan wire to J2-5, to J3-7, red wire, to switch
S-3, the timer switch. When time is selected, S-3 will close the 1-2-3 points. The 120 vac
will now be at one side of the timer also. From S3-2, 120 vac will be on the black wire
to the speed control through the speed control to J3-11.
NOTE:
At this point, the speed control regulates the voltage.
(3) From J3-11 to J5-1 through the normally closed (spring loaded) S2,
run/brake switch, to J5-8, to J1-6, to the brown wire, to one side of the armature.
NOTE:
Reference on F1-2, 120v (hot side).
(4) For the neutral side, 120vac will be at S-1, white wire, through S-1, to
the red wire, to the lid interlock switch, S-4.
NOTE:
S-4 is a number assigned by the school for clarification. The mfg only lists it
as lid interlock.
(5) When the lid is closed, S-4 is closed, and 120 vac will be on the black
wire to J2-11, to J3-1, and jumped with a white/black wire to J3-2 through the pc board
to J1-2. From J1-2, white wire, to the field windings. From the field windings, the
voltage will be variable (depends on speed control setting) to J1-3. From J1-3, pc
board, to J5-4, orange wire to S-2 (run/brake switch), through S-2, to J5-2, brown wire,
pc board, to J1-5. From J1-5, yellow wire, to one side of the armature.
MD0368
2-2