Looking to sub 2SC971 in a Akai x-165d oscillator board. 2SC971 is a TO-5 device with a heatsink. Service manual I found two possible modern subs: ksc2690 (to-126) and ksc2073 (to-220) 2sc971 Pc = 1W cbv = 50v ebv = 7v Ic max = .5A ft = 30mhz hFE = 80 min ksc2073 Pc = 25W cbv = 150v ebv = 5v Ic max = 1.5A. ft = 4mhz hFE = 40 min ksc2690AYS Pc = 1.2w cbv = 120v ebv = 5v Ic max = .1.2A ft = 155mHz hFE = 160 min ksc2690AYS seems like a closer match, ebv is a little low, pins should fit existing holes but its much faster @155mhz. How would this affect oscillator? Would a heatsink be required for new device since heat dissipation is much better?
Exact replacements are apparently still available. https://www.ebay.com/itm/NTE-2SC971...g:q74AAOSwslda0Nkk:rk:1:pf:0&shqty=1#shpCntId The transistion frequency of the KSC2690AYS shouldn't be an issue since it is higher than the original part. Use of an appropriate heatsink is required to allow the transistor to operate at its rated power dissipation.
