Yamaha B-6.
http://www.thevintageknob.org/yamaha-B-6.html
Interesting Carver connection. X-Module explains owner reports of excessive heat in the B-6. Early version of X-Power module made an appearance in R-1000 and R-2000 receivers. The module switches voltage rails. Unfortunately, the module runs very hot. $1300 is excessive given poor cosmetic condition. Interestingly, many B-6 for sale on you know where but there are no completed sales. True value is probably in $400-600 range but expect more cost for a highly recommended full restoration.