The 2SC2509 driver transistors 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.
Parts Required:
Qty
| Description
| Kenwood Part No.
| Circuit Description
|
2 | Driver Transistor | 2SC3133 | Q2, Q3 |
2 | 330 1W Carbon resistors | RC05GF2H331J | R8, R9 |
1 | .047 uF Ceramic capacitor | C91-0119-05 | C2 |
2 | 220 pF Ceramic capacitor | CC45SL2H221J | C64,C65 |
1 | 560 pF Ceramic capacitor | CC45SL2H561J | C63 |
Procedure:
Make the following changes on the HF Final Unit (X45-3400-XX)
- Change C2 to 0.047 uF. This is connected to the base of Q1
- Change C63 to 560 pF. This is conneced to the Emitter of Q1
- Change R8 and R9 to 330 0hm. These are connected to the collectors of Q2,Q3
- Add 220 pF caps (C64,C65) from the collector to emitter of Q4 and Q5
- After install of the new driver transistors (2SC3133) readjust the bias current according to the
instructions contained in the service manual.
- Note:
- C64 and C65 should be soldered directly to the collector and emitter
pins of the final Transistors Q4 and Q5.