Kemppi Mastertig MLS 3003 ACDC Service Manual page 31

Installation of semiconductors
Secondary inverter Z003
Pre-inverter card Z004
For components on Z004, normal procedure must be done when changing the
card. Clean thoroughly surface on the heat sink and place correct amount of heat
sink paste to new parts. Tighten parts as normally, torque 3 Nm.
Negative side IGBTs are
insulated from the heat sink by
mica insulators. Mica insulators
have to be replaced every time
the main circuit card Z003 is
disconnected from heat sink !!!
Heat transferring paste is
applied as thin layers on both
sides of the mica insulators.
Absolutely no impurities are
allowed on surface of the
insulators when mounting them
between the heat sink and the
IGBTs!
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