de WB2CPN 2005.03.04 There was an AC power supply that would slide into the battery compartment of the BC-221. Rectifier was 6X5. Prior to about 1947 we built our own power supplies from Wilcox parts mostly. Height was the main problem, so the power supplies we built had a flat peice of aluminum for a chassis. It was a good idea to remove the door. 73 Clete - 30 -