[Amps] replacement to 3B28 rectifiers in certain HF Amps

[rfdude at comcast.net]

Hi 
i have two solid state replacement assemblies that fit the 4 pin socket of a 3B28 rectifier (as the type used in the Collins 30S1). They are cylidrical, black, and about 1+1/8"  in diamter.
They have a black base, and "pin to cap" they are approx 5.5" long. The standard ceramic cap fits the end (anode). The only markings are: Made in the USA and S5130. A search on the net (google: "S5130 rectifier") led to two other requests for similar info. I leaned that they are Sparkes Tarzian (never heard of them), but there's no details on their PIV and amperage ratings. I am trying to find out if indeed they are a replacement for a 3B28.
Thanks for any info...
kb3bf