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Electronics => Repair => Topic started by: abode091 on October 13, 2023, 06:15:07 am

Title: power supply _ IGBT testing
Post by: abode091 on October 13, 2023, 06:15:07 am

Hello,

I'm repairing a power supply that has multiple IGBTs.
The shorted IGBTs that has C-E resistance of couple Ohms are easy to know that they are broken.

But what about those that have C-E resistance in the Kilo Ohms instead of Mega Ohms, should I consider those dead, damaged or correctly functioning?

Note: the original C-E resistance is around 2.5 MOhms, now its around 8.5 KOhms.

Thank you in advance.

Title: Re: power supply _ IGBT testing
Post by: jonpaul on October 13, 2023, 07:28:07 am

A resistance meas at a few mA in an ohmmeter is not a reliable IGBT indicator.

Also, shorted switches often are due to a more serious load or driver fault.



Remove all the IGBT devices and test on a curve tracer or HV lab PSU.

Place dummy loads on each driver and check driver outputs.

Bon Chance


Jon