[ARC5] Paralleling Rectifier Diodes

[releazer at earthlink.net]

Yesterday I found a 12/24V 10 amp battery charger someone tossed out.  It seems to work fine on the 12V setting but the voltage output is only 22V on the 24V setting even with no load.  Oddly enough it uses a center tapped transformer and two rectifier diodes to produce a full wave output, although without any filter caps.  It seems that one of the rectifier diodes has an excessive voltage drop on the 24V setting.  How would you parallel rectifier diodes, in case I do not have any suitable diodes to replace the defective one?

Thanks

Wayne
WB5WSV