Kemppi Mastertig MLS 3003 ACDC Service Manual page 22

Measurements
Z004 Pre-inverter, rectifier:
- Power should be off !
- With these measurements you can find short circuits and partly open circuits that indicates fault in
the machine.
- Measure diodes in forward and reverse direction. Forward diode threshold voltage is ~0,5V, reverse
direction infinite. See the picture below for instructions.
- Repeat measurements for all six (6) instances. Pin locations marked in the pictures below.
1
3
Diodes*
1.
2.
3.
4.
5.
6.
* Diodes marked with red color in the right hand picture.
Diode 1.
Diode 4.
Measuring points
X1 -> 1
3 -> X1
X2 -> 1
3 -> X2
X3 -> 1
3 -> X3
Diode 1.
X1
X2
X3
Diode 4.
Value
~ 0,5 V
~ 0,5 V
~ 0,5 V
~ 0,5 V
~ 0,5 V
~ 0,5 V
2.
1. 3.
4. 5.
6.
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