Welcome Back Dave
Maybe these guys can help:
Carver audio repair/modifications
B-Man
daddyjt (Carver TFM35(x), TFM55(x) M-500(t))
dennismiller55 (Carver C-1 repair and modifications, other)
Nahash5150 (Carver most anything)
Retriever
wrf (Carver M-400(a,t), most amps, preamps, also Phase Linear)