Albert wrote:

OK, thanks to all who provided some guidance in the original post (see
'low voltage drop transistors for power supply' post.

Clearly, this was a 12v supply and not a 13.8v supply. The actual
output current ratings are not known, the only hint is that the
original meter was a 25 amp meter.

The transformer is much larger than 100 va and is actually larger than
a 200 va unit (based on core size). When I tore down the rest of the
assembly, I found more shaky stuff including sockets for the
transistors that were soldered, several etch cuts and lifted run on
the PCB, meter shunt was missing (probably discarded when the original
pcb was replaced). In other words, it probably needs a complete
redesign rather than using any of the original parts and pc boards.

I ran LTC's power supply design software and it came up with a 13.8
volt output switching supply that will supply 14A with the existing
power transformer. It uses the LTC1775 switching regulator, 2 X
Si4410DY mosfets, an 11 uH inductor and a couple of 1N5818 schottky
diodes. The supply itself (not including transformer losses and
rectifier losses) provides 98 percent efficiency at 14A output.

So, I'm considering building up this switching supply.

I need suggestions for a schottkey bridge rectifier that will handle
20A or more. I find the diodes themselves are readily available, but
I'd like to have a bridge assembly if possible.

Any suggestions??

Yup. Abandon the switcher idea if this is to be used
for a ham station. Put two decent pass transistors in
there. If you are dead set on a redesign, use an LM317
with the pass transistors in collector wrap around
configuration. If you don't want it adjustable, use
a 7812 as if it was an LM317 (gnd leg is the adj leg),
with the resistors chosen to give you 13.8. If it can't
sustain 13.8 across the supply output at full load, use
Watson's suggested boost circuit. When you have that
working to your satisfaction, add a crowbar.

The down-side of the above is not getting to play
with the switcher design. The down-side of the switcher
is noise.