I'm going to guess it is in the module in the middle of the signal board, About 6 inches long and an inch thick, enclosed in a metal case. There are some surface mount electrolytics in there that are probably bad. (4 of them I think).
Unsolder this module and remove it from the signal board, then open it up and replace these 4 caps. I usually just use a good quality radial lead cap rather than putting in new surface mount jobs. There is enough room if you are patient.
I hope I'm thinking of the same chassis as you are.
