| Parameter | Value |
|-----------|-------|
| Frequency range | MW: 520–1710 kHz
LW: 150–450 kHz
SW: 1.6–26.1 MHz (9 bands)
FM: 87.5–108 MHz |
| Sensitivity (SW) | < 10 µV for 10 dB S/N |
| Selectivity | ±4 kHz (-6 dB), ±20 kHz (-60 dB) [AM/SW] |
| IF rejection | > 60 dB (SW) |
| Image rejection | > 40 dB (SW, below 10 MHz) |
| Audio output | 250 mW into 8 ohms |
| Speaker | 2.5 inch (66 mm) dynamic |
| Headphone jack | 3.5mm stereo (mono speaker output) |
| Dimensions | 190 × 115 × 32 mm |
| Weight | 570 g (without batteries) |
| Symptom | Likely cause | Solution | |---------|--------------|----------| | No power | Dead batteries / wrong adapter polarity | Check battery contacts, clean with pencil eraser. Use center-negative adapter. | | Weak or no FM | Whip antenna broken | Replace with 75cm whip (Sangean part). Or clip wire to stub. | | Display digits missing | Bad zebra strip connection | Open case, clean LCD contacts with isopropyl alcohol. | | Tuning knob feels loose | Coupler cracked (plastic) | Replace coupler or 3D print one (DX-390 uses 6mm D-shaft). | | High noise on AM/SW | Internal battery corrosion | Clean board with vinegar, then IPA. Check capacitors near audio amp. | | Memory resets often | Backup capacitor (C203) failed | Replace 0.1F 5.5V supercapacitor (Panasonic EECS0HD104H). | radio shack dx-390 owners manual
Manual solution (Page 15 - Troubleshooting chart): This indicates a failing capacitor in the RF front end, OR you have a cell phone charger plugged into the DC jack. The manual explicitly states: "Use only an unregulated 6V, 300mA adapter. Switch-mode power supplies cause heterodyne whistles." | Parameter | Value | |-----------|-------| | Frequency
Manual solution (Page 22): The previous owner set the "Timer" function. To cancel: Press "Timer" button, then press "Down" arrow until "OFF" appears. Press "Enter." | Symptom | Likely cause | Solution |
| Control | Function | |---------|----------| | POWER/VOLUME | Rotate right to power on and adjust volume | | TUNING (large knob) | Main tuning (variable capacitor / PLL) | | BAND | Select: MW (AM), LW, SW (1–9), FM | | STEP | Tuning step: 1 kHz (AM/SW) or 0.05/0.1 MHz (FM) | | MEMORY | Store current frequency into a preset | | PAGE/CH▼/▲ | Navigate memory pages (0–9) and channels (0–9) | | SCAN | Auto-scan upward for active stations | | LIGHT | Backlight (momentary) | | BEEP ON/OFF | Disables key beep (rear slider) | | LOCAL/DX | Attenuator for strong AM/SW signals |