so I have this diode that is under a transformer on a battery charger. I was looking for faults on it with a thermal camera and noticed the one next to it was glowing at over 120C . I removed the hot one and it is pretty much shorted as shows 0.03 in both directions with the diode test. Iv also got a peak tester dca 75 and it won't even identify it as a component.
The one next to it is marked with V21 and is just a regular looking brown / orange looking colour and is glass.
I would go on what the dca 75 says, but each time it tests the working one, the vf goes up.
It's been so hot that it's burnt 99% of the markings off it, but it looks to be paired with the one next to it.
The problem is I can't seem to find a replacement for it. "V21 Zener diode" just brings up an smd diode sot 23 package and not a through hole glass diode like this.
Best Answer
SMD devices typically are marked with random letters/numbers, but through-hole devices usually try to use markings that resemble the actual name.
"V21" sounds like the BAV21, which is a general-purpose diode made by many manufacturers.