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TROUbLESHOOTING

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REMOTE CONTROL CHECK

2. Power Diode Test

 

Disconnect the remote output control and connect an ohmmeter across 75 to 76 and rotate the rheostat in the remote control. The resistance reading should go from zero to 10K ohms. Repeat with ohmmeter across 75 and 76 with same results. Connect ohm- meter across 75 and 77. The reading should be 10K ohms. A lower reading will indicate a shorted or par- tially shorted rheostat. A very high reading will indi- cate an open rheostat. In either of the last two cases, replace rheostat. Check cable for any physical dam- age.

POWER RECTIFIER bRIDGE ASSEMbLY

CHECKING PROCEDURE

a)Establish the polarity of the ohmmeter leads and set to X10 scale.

b)Connect the ohmmeter positive lead to anode and negative lead to cathode.

c)Reverse the leads of the ohmmeter from Step b.

d)A shorted diode will indicate zero or an equally low resistance in both directions. An open diode will have an infinite or high resistance in both directions and a good diode will have a low resistance in Step b and Step a much high- er resistance in Step c.

WARNING

ELECTRIC SHOCK can kill.

•Have an electrician install and ser- vice this equipment.

•Turn the input power off at the fuse box before working on equipment.

•Do not touch electrically hot parts.

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1.bridge and Device Isolation (See the instruc- tion manual parts list for the exact location.)

Disconnect the following leads from the bridge, shown in Diagram 1:

a)Unplug P3 (G1, G2, G3 and 204) from the Control PC Board.

b)Unplug P5 from the Snubber PC Board.

c)Secondary leads X1, X2, and X3 from the anodes of the SCR’s and cathodes of the diodes.

d)Disconnect positive bridge lead from shunt and positive capacitor bank lead and from lug with triple 204 leads.

e)Perform the following steps 2 and 3. If diodes and SCR’s are not shorted, bridge test is com- pleted. If any device appears shorted, discon- nect the cathode lead of each diode (4 total) and repeat Steps 2 and 3.

3.Power Silicon Controlled Rectifier Test

a)Connect the ohmmeter (set to m X10 scale) leads to the anode and cathode.

b)Reverse the leads of the ohmmeter from Step a.

c)A shorted SCR will indicate zero or an equally low resistance in one or both directions.

d)Establish the polarity of the ohmmeter. Connect the positive lead to the gate and the negative lead to the cathode.

e)An open gate circuit will have an infinite or high resistance. A good gate circuit will read a low resistance, but not zero ohms. If gate circuit reads zero ohms, check gate harness for shorts between gate leads and 204 before replacing SCR.

CAUTION

If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact your Local Lincoln Authorized Field Service Facility for technical troubleshooting assistance before you proceed.

IDEALARC® DC-400

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Lincoln Electric DC-400 manual Remote Control Check, Power Diode Test, Power RECTIFIER bRIDGE ASSEMbLY, Checking Procedure
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DC-400 specifications

The Lincoln Electric DC-400 is a versatile and robust DC arc welding power source designed to meet the demands of various industrial applications. Known for its reliability and performance, the DC-400 is ideal for both professional welders and fabrication shops requiring robust equipment that can handle challenging welding tasks.

One of the main features of the DC-400 is its ability to provide a smooth, stable arc, which is essential for achieving high-quality welds. This welding machine is capable of delivering a wide amperage range, typically from 20 to 400 amperes, making it suitable for various welding processes, including MIG, TIG, and Stick welding. The unit's high output capabilities allow it to effectively weld a variety of materials, such as steel, stainless steel, and various alloys.

In terms of technology, the DC-400 integrates advanced power conversion technology that enhances energy efficiency while minimizing heat loss during operation. This not only contributes to lower operating costs but also ensures a longer service life for the machine. The DC-400 features a durable, rugged design, with a robust steel frame that can withstand the rigors of heavy industrial use while providing an IP23 rating for protection against moisture and dust.

Another notable characteristic of the DC-400 is its ease of use. The intuitive controls allow for quick adjustments to settings, enabling welders to easily adapt to different job requirements. The arc characteristics of the DC-400 can be fine-tuned to optimize performance for different welding applications, ensuring consistent results every time.

Moreover, the DC-400 is equipped with built-in safety features such as thermal overload protection, which prevents damage to the machine in case of prolonged operation under heavy loads. This feature enhances the safety of the operator and extends the life of the welding machine.

Overall, the Lincoln Electric DC-400 stands out as a reliable and efficient welding power source. Its combination of high-performance capabilities, advanced technology, and next-level usability makes it a popular choice in the industry. Whether for heavy fabrication, maintenance, or repair work, the DC-400 continues to prove itself as an indispensable tool for professional welders seeking quality and durability in their equipment.
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