Lincoln Electric IDEALARC SP-255 Service Manual page 95

F-42
PROCEDURE
1. Disconnect lead #208 and Trans-
former Lead X1 from the heat sink on
the left side of the machine (facing
the front) using a 1/2" socket wrench.
See Figure F.15.
a. Thin lead is always on the out-
FIGURE F.15 - Heat Sink lead discon-
nection.
2. Disconnect lead #204 and heavy
lead from the middle heat sink with a
1/2" socket wrench and 1/2" open
end wrench. See Figure F. 16.
3. Remove the diode lead from the neg-
ative capacitor band buss bar on the
right side of the machine using a slot
head screwdriver and 3/8" open end
wrench.
FIGURE F.16 - Heat Sink lead discon-
nection.
TROUBLESHOOTING & REPAIR
SCR OUTPUT RECTIFIER REMOVAL
board side of the connection.
IDEALARC
4. Cut the SCR gate leads G1 and G2
(see wire markers and wiring dia-
gram) using wire cutters.
a. The easiest access to these
leads is from the right side of the
machine.
b. Cut any necessary cable ties.
5. Remove the four screws holding the
SCR Assembly to the floor of the ma-
chine using a 5/16" nut driver.
6. Pivot the SCR Assembly counter-
clockwise to provide access to the
right side heat sink.
See Figure F.17.
FIGURE F.17 - Heat Sink Lead Discon-
nection
7. Remove lead #209 and Transformer
Lead X4 from the right side heat sink
using a 1/2" socket wrench and 1/2"
open end wrench.
8. Clear the leads and carefully remove
the SCR Rectifier Assembly.
NOTE: When installing the SCR Rectifier
Assembly, apply a thin coating of Dow
Corning #340 Compound to the electrical
connections.
® SP-255
F-42