From FB group I take …
Alejandro Cruz
He said a diode is a diode but there are more than volts and current. The reverse recovery time is important. If it is rectifying 50 or 60 Hz AC then standard recovery time is good. If it’s rectifying high frequencies then it should be fast recovery or ultrafast recovery.
If you have substitute diodes fail, then you have something else wrong. It could be a bad filter capacitor. Or the transformer may have a problem. Or something downstream may be causing excessive current.
One thing old time troubleshooters used to do was put a 60 watt incandescent light bulb in series with the incoming AC line to limit the current. That gives a chance to measure the voltage and find out while the equipment is power limited.
