Thanks; this is a great help. You're right; no one seems to stock them but
I did find some with the lesser (but still sufficient) current rating but a
higher voltage rating and ordered a couple. In the meantime my equipment
dealer got back to me and they have'em (hopefully the exact one) so I'm
getting one from them too. I don't mind having spares. Thank you again.

Steve,
I think the Silicon Power Cube brand has become absorbed through a
series of acquisitions and mergers into the Crydom brand.
Your pictures show what looks like a dual SCR module. From your
description of the application, I'll bet that the Crydom B551SE-2T or
B561SE-2T (or equivalents) will work for you. The datasheet is at
http://www.datasheetarchive.com/pdf/802496.pdf.
Newark lists them as nonstocked items, but will drop-ship from the
manufacturer.
http://www.newark.com/72M7087/suppli...t.us0?sku=CRYD
OM-B551SE-2T&_requestid=89444. Digikey lists them online at
http://www.digikey.com/scripts/DkSea...name=B551SE-2T
-ND but shows no stock. Don't know if they will drop-ship. You'll
have to ask.

Cheers!!!!!