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TROUBLESHOOTING & REPAIR | ||
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SCR OUTPUT BRIDGE REPLACEMENT
FIGURE F.23 - SCR Output Bridge Removal
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10.Cut any necessary cable ties to allow for the SCR bridge assembly removal.
11.Using a 1/2” socket wrench, remove the four screws (2 on each side) holding the transformer side panels and SCR assembly rails to the main transformer. See Figure F.23.
12.Remove leads #217 and #222 from resistor R2 located on the lift bail assembly. Remove resistor R2 using a 7/16” wrench.
13.With the 5/16” socket wrench, remove the bottom six screws hold- ing the front panel assembly to the base. Carefully pull the front panel forward to allow room to remove the SCR bridge assembly.
14.Clear all leads and carefully remove the SCR bridge assembly.
NOTE: Upon reassembly, apply a thin layer of Lincoln E1868 (Dow Corning
340)heat sink compound to all bolted electrical connections on the aluminum heat sinks.
CAUTION
UPON REASSEMBLY, THE SCR BRIDGE ASSEMBLY MUST BE ELEC- TRICALLY ISOLATED FROM GROUND.
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15.Place insulators between SCR bridge assembly and the output rectifier mounting bracket (see Figure F.23). Check for electrical isolation with an analog ohmmeter.
CAUTION
MINIMUM ACCEPTABLE RESIS- TANCE TO GROUND IS 500,000 OHMS.
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