Hypertherm MAX42, Service Manual

Page: 40 / 100

MAINTENANCE
MAX42 Service Manual Page 3-5
No
1
From page 3-4
Yes
Check input rectifier bridge on PCB3
for short or open. Replace PCB3 if
faulty ( Fig. 4-1 [13] ).
Meter should
indicate 90-115
ohms?
No
Note
If the input rectifiers are shorted,
there is a possibility that one of the
FET packs may be blown ( Fig. 4-11
[4] ). Look for a crack or fracture of
the potting. There is also a possibil-
ity that one of the capacitor packs
may be blown ( Fig. 4-8 [ 2] ). Look
for damage or dark discoloration.
Indication is low
or
0 ohms?
Indication is
high or infinity?
Yes
Meter indicates a
short?
Replace PCB3.
Yes
No
2
Yes
Disconnect cables W132 - 135 from
TB1 ( Fig. 4-8 [6] ). Measure the
resistance across each inductor,
L2-L5, ( Fig. 4-1 [11] ) between the
disconnected cable terminal and
power switch S1. Observe for an
indication of 1 ohm or less.
Meter
indicates 1 ohm
or less for each
inductor?
No
Replace faulty
inductor ( Fig. 4-
2 [ 4] ).
3
Yes
To page 3-6
To page 3-6
Measure resistance of input
rectifier bridge on PCB3.
Observe for short.