i have a 76’or 78, grestch expander-b bass head and box, its 200 watts and my dad has owned since new and he used it twice a week in a pub band since buying it,and knowone seems to know anything about it.so if you could give me any info, on it that would be good. if you need the serial no. just tell me were to look. also if i can get parts for it,that would be great. andrew.