FOR SALE: SOLID STATE RECTIFIER REPLACEMENTS 1N1239 plug-in rectifier with octal base. Ideal for use with 516-F2 Collins Supply. These are made by Semicon Inc. Plug-in solid state replacement for vacuum tubes 5R4 & 5U4. Octal base. Rated @ 2800 vdc, 1 amp. List price $18 to 20.00 each Qty 5 available for $12.00 each. Shipping additional.