bridge rectifier 1N4721

[zamproject]

Hey

I'm looking for replacement to 1N4721
I'm cleaning a "big" psu and i'm suspicious about one of these 1N4721 (made sound when shaked !!!) even if she look good at diode test.
Anyway it's an hot spot and i want to redone all solder joint here, it's a 35 years old PSU
The "trafo" unit have big transformer with 3 seconday, 3 bridge and filtering caps. 3 card with regulator (3A) follow.
I have candidate in the 3A 200v range (like the 1N4721)
UF3003
STH302
UF5402
but none of those come to the 1N4721 300A max surge current, this parameter is important for inrush current right?
I have no idea what's needed here and if 130/150A is OK ?

NOS 1N4721 are just prohibitive :-X

Zam

 

[JohnRoberts]

A more modern part will probably be OK.

The peak surge current will be limited by several other factors in use. The transformer winding resistance and even your house wiring adds series resistance that could prevent 300A from ever happening.

Diode peak current is generally a thermal/mechanical specification. The diode failure mechanism from over-current is simply that the diode melts, so package dissipation and thermal mass (size) can affect this peak current specification.

JR

 

[zamproject]

Tks JR

Regarding datasheet i think i go for UF5402, 150A max (best i find in the 3A 200V range) and better rating temp.
It's the same about max reverse peak current?
1N4721 is 25uA
UF5402 is 10uA

Zam