Switchable ballast repair

[FONT=&quot]Picked up inoperative Hydrofarm 400W switchable ballast on Craig's List. My visual inspection reveals burnt/charred wiring on ballast transformer that I've concluded must be replaced (transformer). My question: can I purchase a ballast repair kit for a MH light and use that transformer for repair or must I purchase a 400W Switchable ballast repair kit? Thanx [/FONT][FONT=&quot][/FONT]