Maintenance - Lincoln Electric INVERTEC 170S Service Manual

WARNING
ELECTRIC SHOCK can kill
Have an electrician install and service this
•
equipment.
Turn the input power off at the fuse box
•
before working on equipment.
Do not touch electrically hot parts.
•
Prior to performing preventive
•
maintenance, perform the following
capacitor discharge procedure to avoid
electric shock
INPUT FILTER CAPACITORS
DISCHARGE PROCEDURE
This procedure will drain off any charge stored in
the four capacitors that are part of the Inverter
Board assembly. This procedure MUST be
performed, as a safety precaution, before
conducting any test or repair procedure that
requires you to touch internal components of the
machine.
Secondary side circuit
Figure 1 - Capacitors discharge location

MAINTENANCE

1. Remove input power to Invertec 170S
machine
2. Remove the cover following the instruction
available in this Service manual.
3. Obtain a high resistance and high wattage
resistor ( 25-1000 ohms and 25 watts
minimum ). This resistor is NOT supplied with
the machine. NEVER USE A SHORTING
STRAP FOR THIS PROCEDURE.
4. Locate the resistor R86 that is directly
connected to the terminals DC+ and DC – on
the main board, See Figure 1 and check the
voltage across it, it should be zero; if not
follow the next step.
5. Use electrically insulate gloves and insulated
pliers. See Figure 1a. Hold the body of the
resistor and connect the resistor leads across
the resistor R86. Hold the resistor in place for
10 seconds. DO NOT TOUCH CAPACITOR
TERMINALS WITH YOUR BARE HANDS.
6. Check the voltage across the resistor R86.
Voltage should be zero. If any voltage
remains, repeat this procedure.
Primary side circuit
Page8
Figure 1a
DC +
R86
DC -