36 Sirina Erasitexniko May 2026

| Symptom | Likely Fix | |---------|-------------| | No sound | Replace battery/check polarity. Check speaker coil continuity. | | Weak buzzing | Bad capacitor (100–470µF near LM386). Replace. | | One tone only | Rotary switch corroded. Clean with contact spray. | | Screaming feedback | Microphonic piezo. Add rubber gasket. | | Overheats | Short circuit across output transistor (BD139 common). |

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| Feature | Specification | |---------|----------------| | | Piezoelectric or electromagnetic siren | | Voltage | 12V DC (car battery) or 9V battery | | Current draw | 150–300 mA max | | Sound output | 105–115 dB @ 1m | | Tones | Fixed howl, alternating fast/slow wail, or “hi-lo” (European police) | | Activation | Momentary switch, relay, or 36-pattern selector (hence the “36”) | | Housing | ABS plastic, red or black, 80x80x40 mm | | Mounting | Screw holes or magnetic base | | Origin | DIY kit from Hellenic Amateur Radio Association (RAAG) or small Greek manufacturer like Sirina S.A. (if existed) | 36 sirina erasitexniko