Lincoln Electric SP-250 service manual Leads

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F-20

TROUBLESHOOTING & REPAIR F-20

STATIC SCR RECTIFIER ASSEMBLY TEST

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TEST PROCEDURE

1.Disconnect main AC input power to the machine.

2.Disconnect Plugs J3 and J6 from the G2252 Control Board or remove Plug J3 from the G1992 Control Board (Code 9402 only.) This elec- trically isolates the SCR bridge assembly. See Figures F.2A and F.2B.

SP-250 CONTROL

G2252

J2

J8

J7

J4

J9 J3

J5 J6

FIGURE F.2A - Remove Plugs J3 and J6 to Perform Static SCR Rectifier Assembly Test.

SP-250 CONTROL

G1992

J2

J8

J7

J4

J9

J5

3.Test with an Analog Volt-Ohm meter that capacitors have completely dis- charged.

4.Disconnect leads X2 and X3 from the negative capacitor bank using a fi" open end wrench. See Figure F.3.

LEADS

X2 AND X3

NEGATIVE

CAPACITOR

BANK

BUSS BAR

FIGURE F.3 - Location of Leads X2 and X3.

5.Separate leads X2 and X3 from the negative capacitor bank buss bar. Be sure there is no electrical con- tact. See Figure F.3.

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J3J6

FIGURE F.2B - Remove Plug J3 to Perform Static SCR Rectifier Assembly Test.

IDEALARC SP-250