Main Transformer And Output Choke Removal And Replacement - Lincoln Electric POWER MIG 255 SVM144-B Service Manual

F-52
LEAD
X1
OUTPUT
CHOKE
POSITIVE
LEAD
MAIN
TRANSFORMER
PROCEDURE
1. Disconnect main input power to the
machine.
2. Remove the case side panels using a
3/8 in. nutdriver.
3. Test that the capacitors are discharged
using a volt ohmmeter. Polarity must
be observed.
4. Remove lead X1 from the left side SCR
heat sink assembly using a 1/2 in. sock-
et wrench, extender and universal
adapter. See Figure F.17.
5. Remove lead X4 from the right side
heat sink assembly using a 1/2 in. sock-
et wrench, extender and universal
adapter.
TROUBLESHOOTING & REPAIR
MAIN TRANSFORMER AND OUTPUT CHOKE
REMOVAL AND REPLACEMENT (continued)
FIGURE F.17 — MAIN TRANSFORMER REMOVAL.
LEADS
X2 AND X3
POWER MIG 255
OUTPUT
CHOKE
LEAD
NOTE: PLUG-IN LEADS ARE
NOT SHOWN FOR
CLARITY.
LEAD
X4
POWER
ENHANCEMENT
CHOKE
6. Remove the two transformer secondary
leads X2 and X3 (braided copper strap)
from the negative capacitor bank buss
bar using two 1/2 in. open end wrench-
es.
7. Disconnect and label all transformer
leads from the reconnect panel using a
3/8 in. open end wrench.
8. Disconnect and label all leads from the
input power switch.
9. Remove the power switch.
10. Disconnect thermostat leads #320 and
#320B from the SCR Rectifier.
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