What part can I replace it with?

whit3rd said:

That can't be right; secondary rectifier failure is due to overheating, and excess downstream
currents, such as caused by a filter capacitor short, are certainly a possible cause.
Overheated semiconductors re-diffuse, and that almost always makes short-circuit failures,
such as second-breakdown in power transistors.

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rjenkinsgb said:

One of the commonest causes of semiconductor failure is thermal cycling.
That is due to differences in expansion between the semiconductor wafer, it's connecting leads, the encapsulant, and possibly with the PCB adding to the stresses, depending on the package type and mounting.

Another is the repeated short-term overloads at switch-on, if the components are not rated adequately to allow for the brief current spikes as other parts charge up to their operating voltages; again, a thermal shock effect.

Neither needs an external fault condition to cause the failure.

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Abraham90 said:

Tried to replace the PWM IC

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