Lincoln Electric RED-D-ARC E500 - Manual (Page 17)

D-7 TROUBLESHOOTING D-7
E500
Low output, low OCV
, or erratic welding
T
urn control pot. to minimum
Check OCV
OCV is 35-55V
OCV is 40-45V
OCV is 0
Rated OCV but
OCV less than rated
erratic welding
but more than 55V
OCV 45-55V
OCV 35-45V
Possible machine
Check leads 76, 77,
Possible
Loose lead
Possible intermittent
Possible
Possible wrong connection
Possible defective
is being
212, 213, 210, 21
1
defective
connections
or loose connections
defective
of gate leads if recent
PC board
single phased
& SW2 for open
PC board
on shunt
in control circuit.
PC board
PC board or rectifier
Check aux. voltages
Check PC board con-
stack change.
on PC board
nector
, switches,
potentiometers, etc.
201-202 = 120V ±
10%
Replace
Retighten
Replace
See wiring diagram
Replace
201-202 = 120V ±
10%
leads
and correct
202-203 = 120V ±
10%
Remove and replace Gate leads
G-1, G-2, G-3 from PC board
one at a time.
If aux. voltages
are incorrect,
If aux. voltages
If removing each gate lead
If removing and replacing
check &
repair
.
are OK
one at a time changes OCV
each gate lead one at a
time does
NOT
change OCV
Codes below 9500
with power of
f, remove leads from
Identify gate lead that, when
Codes above 9500
75, 76, 77 terminal strip and
removed, OCV did not change.
with power of
f, disconnect
welding leads from output terminals
Remove gate lead. V
oltage
remote control amphenol
between gate lead and 204 must be 13-17V
.
and welding leads from
output terminals.
Check resistance of each
If voltage OK
If voltage is
terminal on this terminal
not correct
strip to ground. Resistance
Check the following pins
must be as follows:
Defective power SCR
for resistance to ground.
75-GND 2K minimum
Possible defective
Resistance must be as
76-GND 2K minimum
PC board
follows:
77-GND 12K minimum
Replace
75-GND 2K min. 76-GND 2K min.
Replace.
77-GND 12K min.
If not, clear terminal strip
If resistance is OK,
and leads, and also check
possible defective
If not, examine amphenol
SW2 and R1 for dirt.
PC board.
assembly for faults.
If fault found, repair or
If amphenol OK, possible
replace amphenol assembly
.
defective PC board.