Lincoln Electric POWER WAVE C300 Service Manual page 49

F-30
SWITCH BOARD TEST PROCEDURE (continued)
TABLE F.6 – SWITCH BOARD RESISTANCE MEASUREMENTS
Description
100 O hm Pre -Ch arge
Resistor
Pre -Charge Relay
Coil Resistance
"Buck " Converter
IGB Ts
"Buck " Converter
Diode
"Boost " Converter
IGB Ts
"Boost " Converter
Diode
Ful l Bridge High Side
IGB Ts
TROUBLESHOOTING AND REPAIR
Meter Test Points
and Polarity
B10( +)
To
B12 (-)
J41 Pin 5 (+)
Receptacle on Switch
Board
To
J41 Pin 6( -)
Receptacle on Switch
Board
B12( +)
To
B28( -)
B28( +)
To
B49( -)
B49( +)
To
B29( -)
B48( +)
To
B29( -)
B48( +) To
B37( -)
Also
B48( +) To
B41( -)
POWER WAVE® C300
Expected Readings
100 Ohms
15,000 to 30,000
ohms dependent on
meter being used .
Two diodes are in the
circuit path to the
relay coil.
High Resistance
Greater than 100,000
ohms
Typical failure is a
"short"
High Resistanc e
Greater than 100,000
ohms
Typical failure is a
"short"
High Resistance
Greater than
100,000 ohms
Typical failure is a
"short"
High Resistance
Greater than
10 ,000 ohms
Typical failure is a
"short"
High Resistance
Greater than
10,000 ohms
Typical failure is a
"short
Conditions
Machine "o ff" no
input power applied
Machine "o ff" no
input powe r applied.
Plug J41 removed
fro m the Switch
Board.
Machine "o ff" no
input power applied.
The input choke
disconnected from the
Switch Board at B2 8.
Machine "off" no
input powe r applied.
The input choke
disconnected from the
Switch Board at B28
Machine "o ff" no
input power applied.
The input choke
disconnected from the
Switch Board at B28
Machine "of f" no
input powe r applied.
The input choke
disconnected from the
Switch Board at B28
Machine "o ff" no
input power applied.
The Pla nar
Transfor mer
electrically isolated
fro m the switch bo ard
at test points B37 an d
B41 .
F-30