Troubleshooting & repair, Output rectifier test (continued) – Lincoln Electric POWER WAVE SVM173-A User Manual
Page 94
TROUBLESHOOTING & REPAIR
F-48
F-48
POWER WAVE 455M/MSTT
STT OUTPUT
TERMINAL
POSITIVE (+)
OUTPUT
TERMINAL
NEGATIVE (-)
OUTPUT
TERMINAL
POWERWAVE 455/R
I ON
O OFF
FIGURE F.15 – OUTPUT RECTIFIER TEST
OUTPUT RECTIFIER TEST (CONTINUED)
TEST PROCEDURE
1. Remove main input supply power to the
Power Wave 455M.
2. Remove any output load that may be con-
nected to the Power Wave 455M.
3. With the analog ohmmeter, measure the
resistance between the positive and nega-
tive output terminals (NOT the STT termi-
nal). Refer to Figure F.15.
4. If the reading is approx. 50 ohms, the output
rectifier modules are not shorted. If the
reading is less than 10 ohms, one or more of
the rectifier modules are shorted. Reverse
meter probe and verify low reading. Refer to
the Output Rectifier Module Replacement
procedure.
5. Remove the case top perform the Input
Filter Capacitor Discharge procedure.
IMPORTANT: The positive (+) meter probe
must be attached to the positive (+) output ter-
minal and the negative (-) meter probe must be
attached to the negative (-) output terminal.
6. Using the 5/16” wrench, remove and insu-
late lead 202A from the negative output ter-
minal. Repeat step 4 to confirm.
7. Reconnect lead 202A to the negative output
terminal.
8. Replace the case top and sides.