Disclaimer I am not saying this info is 100% perfect but I did try doing a bit of research hoping it would help you all ..a bit of research...these are the original part numbers FROM THE SERVICE MANUAL which I cross checked with the PRB line
http://www.russellind.com/prbline/xref/jvc.htm
If you can't get them (links below) & still want help I'll be glad to help, don't worry
VKB3001-012 Capstan Belt SCX7.0 (square cut, .040-.049 inch/1mm thick, inner circumference 7inches)
http://www.partstore.com/Part/Matsushit ... 2/New.aspx
VKB3000-017H Take up belt SCX4.6 (square cut 1mm thick, inner circumference 4.6 inches)
http://www.partstore.com/Part/Matsushit ... H/New.aspx
VKB3000-031H Counter belt SCY5.2 (square cut .035-.039 inch thick or 0.8mm inner circumference 5.2inches)
No longer available??...don't worry
http://www.mcmelectronics.com/product/D ... -2-/SCY5.2
Pardon my ignorance ...but does this beast lack a flat belt?