Rap 2.5 Dc Power - Challenge CMT-130TC Service Manual

RAP 2.5 DC Power

This procedure troubleshoots the 5, 15, 24 VDC
power supplies.
WARNING
Lockout power! Perform the Power Lockout
Procedure on page ix before removing and
installing components.
WARNING
HIGH VOLTAGE! Use extreme caution when
testing high voltage lines. Serious injury or
death may result from unsafe testing prac-
tices.
1. Switch the main power OFF using the
red/yellow switch on the front of the trimmer,
and lock out power to the machine.
2. Remove the electrical panel door located on
the lower right side of the machine. Visually
inspect all circuit breaker switches to see if
any are tripped or turned off. Are all circuit
breakers ok?
Y N
Reset tripped or off circuit breakers. If a cir-
cuit breaker continues to trip, use applicable
schematic to troubleshoot affected circuit
(Section 7, Wiring Data).
3. Unlock main power and switch power ON.
4. Is there 120 VAC between wire 21 at CB3
and wire 22 at T1, and also 120 VAC be-
tween wires 24 and 25 at EMI filter #2 (Fig-
ure 2-2)?
Y N
Go to RAP 2.4 Input Power
2. Status Indicator RAPs
5. Check the following AC voltages (see Figure
2-4 for wire locations):
8VAC between the red wire at H5-1 and
red/yellow wire at H5-2.
8VAC between the red wire at H5-3 and
red/yellow wire at H5-2.
16VAC between the red wire at H5-1 and
red wire at H5-3.
12VAC between the blue wire at H5-7 and
the blue/yellow wire at H5-9.
12VAC between the blue wire at H5-8 and
the blue/yellow wire at H5-9.
24VAC between the blue wire at H5-7 and
the blue wire at H5-8.
Do all these voltages measure correctly?
Y N
Disconnect main power and replace T2
transformer (Figure 2-4) (PL 5.16 Power
Panel EE-3503 (1/2)).
6. Check the following AC voltages:
9 VAC between wire 18 at CB9 and wire 22
near CB9 (see Figure 2-4).
19 VAC between wire 47 at CB8 and wire 48
at BR1.
53 VAC between wire 19 at the IR relay and
wire 78 at CB7.
Do all these voltages measure correctly?
Y N
Disconnect main power and replace the T3
transformer (Figure 2-4) (PL 5.16 Power
Panel EE-3503 (1/2)).
7. Is there 19 VAC between wires 48 and 49 at
BR1 (Figure 2-4)?
Y N
Reset circuit breaker CB8. If circuit breaker
continues to trip, use applicable schematic
to troubleshoot affected circuit (Section 7,
Wiring Data). Check and repair wires 48 and
49.
MAY 2019
2-12
8. Is there 5 VDC between wires 7 and 8 at the
main PWB (Figure 2-4)?
Y N
Disconnect main power and replace main
PWB (PL 5.16 Power Panel EE-3503 (1/2),
REP 4.23 Main PWB Replacement).
9. Is there 15 VDC between wires 63 and 74
(Figure 2-4)?
Y N
Disconnect main power and replace main
PWB (PL 5.16 Power Panel EE-3503 (1/2),
REP 4.23 Main PWB Replacement).
10. Is there 24 VDC between wires 73 and 74 at
BR1 (Figure 2-4)?
Y N
Check for an open diode on bridge rectifier,
BR1 (Figure 2-4). Is the bridge rectifier
okay?
Y N
Disconnect main power and replace the
bridge rectifier (PL 5.16 Power Panel
EE-3503 (1/2)).
Check and repair wires 73, 74, 48, and 49.
DC power is normal.
CMT-130TC Book Trimmer