I have 4 solid state replacements for the 866 and/or 3B28 rectifiers. They are marked ED9840 and EDI 8117. These seem a little taller than other ones I've seem. They are 1.25" in diameter and 7.5" high. They are used but test fine using my 300 volt DC supply. Sell all four for $60 postpaid within the US. 73, George W7HDL