This is the R-390A tube complement. Get an stock of these tubes if you want to keep your unit working for long time. The most difficult to find are the 3TF7 ballast and the 26Z5W rectifiers, so look for them at hamfests!
Ref. | Tube | Function |
V201 | 6DC6 | RF amplifier |
V205 | 5814A | Calibrator oscillator, 100 KHz cathode follower |
V206 | 5814A | 100KHz multivibrator |
V202 | 6C4 | First mixer |
V207 | 6AK5W | First crystal oscillator |
V203 | 6C4 | Second mixer |
V401 | 6AK5W | Second crystal oscillator |
V204 | 6C4 | Third mixer |
V701 | 6BA6W | VFO |
V501 | 6BA6W | First IF amplifier |
V502 | 6BA6W | Second IF amplifier |
V503 | 6BA6W | Third IF amplifier |
V504 | 6AK6 | Fourth IF amplifier |
V506 | 5814A | Detector, AGC time |
V509 | 5814A | IF cathode follower, AGC rectifier |
V508 | 6BA6W | AGC amplifier |
V505 | 6BA6W | BFO |
V507 | 5814A | Limiter |
V601 | 5814A | First AF amplifier, cathode follower |
V602 | 5814A | Second AF amplifier (line and local) |
V603 | 6AK6 | AF out local |
V604 | 6AK6 | AF out line |
V801 | 26Z5W | Rectifier |
V802 | 26Z5W | Rectifier |
V605 | 0A2 | Voltage regulator |
RT510 | 3TF7 | Current regulator |