How to confirm if mainboard inside max Series inverter is normal

How to confirm if mainboard inside max Series inverter is normal

Boost Circuit and DC-AC circuit have some IGBTs, they bear large current, if mainboard can’t work, most of time, it is caused by them, so when you suspect that mainboard is faulty, you can test them.

Turn to Diode position on multimeter

BUS+, BUS- Position

BUS Voltage is produced by BOOST Circuit on mainboard and imported into IO Board BUS+, BUS-

Boost circuit Testing position

1. Left Terminals on SPD board

There are 4 terminals from positive , negative side of PV system on SPD board, you can test Each terminal with BUS+ like below:

2. Right Terminals on SPD board

There are 4 right terminals from positive , negative side of PV system on SPD board, you can test Each terminal with BUS+ like below:

3. PV input Left Terminals on SPD board

4. PV input Right Terminals on SPD board

dC-aC circuit Testing position

R phase upside IGBT

S phase upside IGBT

T phase upside IGBT

R phase Downside IGBT

S phase Downside IGBT

T phase Downside IGBT