The 2SC2509 driver transistor are no longer available. They have been discontinued by the manufacturer. A substitute transistor (2SC3133) is available but requires some minor circuit changes. These changes are detailed below.
Qty Description Kenwood Part No. Circuit description
2 Driver transistor 2SC3133 Q2, Q3
2 330 ohm 1 watt carbon resistor RC05GF2H331J R8, R9
1 .047 µF ceramic capacitor C91-0119-05 C2
2 220 pF ceramic capacitor CC45SL2H221J C64, C65
1 560 pF ceramic capacitor CC45SL2H561J C63
Note: C64 and C65 should be soldered directly to the collector and emitter pins of the final transistor Q4 and Q5.
Time required for this modification is 60 minutes or less.