Have the same model and same issue. Did you come up with a solution?

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Direct answer to the question – Yes. In > 90 % of the RolloTron 1550 cases with a permanently rapidly flashing LED and no reaction to keys the root cause is a dried-out electrolytic capacitor in the switch-mode power supply. – Replacing the small “start-up” capacitor typically 10 – 47 µF 50–63 V, low-ESR, 105 °C and, if already stressed, the secondary 5 V filter capacitor immediately restores normal operation. – If you do not want to open a 230 V device, a complete unit swap is the safe alternative. --- Detailed problem analysis 1. Symptom correlation • Rapid, steady LED flashing ⇒ µC constantly resets because its 5 V rail collapses. • No keypad response ⇒ firmware never leaves the boot sequence. • Motor is silent ⇒ TRIAC bridge never gets an enable command. 2. Theory of failure • The RolloTron 1550 uses a fly-back SMPS BP531x or TNYxxxx series fed from rectified mains. • A small electrolytic on the primary side provides the start-up energy for the PWM controller; its ESR rises with ageheat. • Once ESR > ~10 Ω, the IC brown-outs, the 5 V rail falls below the POR threshold, the LED driver restarts – hence the infinite blink loop. 3. Confirmation measurements if you own a meter • Board still connected to mains, red probe on C15 5 V rail, black on GND: you will read 2–3 V saw-tooth instead of clean 5.0 V. • After capacitor replacement the rail is a flat 5.02 V and the MCU boots instantly. 4. Component mapping production variants ┌──────────┬──────────────┬─────────────┐ │Designator│ Factory part│ Replace by… │ ├──────────┼──────────────┼─────────────┤ │ C3 C5 │ 22 µF 50 V │ 22 µF 50 V low-ESR, 105 °C e.g. Nichicon PW│ │ C15 │ 100 µF 16 V │ 100 µF 25 V low-ESR, 105 °C │ └──────────┴──────────────┴─────────────┘ 5. Work procedure qualified personnel only 1. Isolate circuit at the breaker, wait 5 min. 2. Remove belt, unhook unit, open housing four clips. 3. Discharge primary cap with 47 kΩ resistor. 4. Unsolder the suspect capacitors. 5. Clean pads, solder replacements with correct polarity. 6. Inspect for cracked joints around the TNY switcher and opto-coupler; resolder if dull. 7. Re-assemble, set upper lower end-positions anew. 6. When the fix is not enough • Bridge rectifier short → mains fuse trips. • Reed contact failure → motor runs but stops randomly LED steady. • MCU flash corruption extremely rare → only factory service can re-flash. --- Current information and trends • Field reports from 2023–24 on Elektroda, Haustechnik-Dialog and Reddit confirm capacitor ageing as the predominant issue usually after 6–10 years of service in warm wall boxes. • Rademacher’s current production RolloTron Comfort DuoFern switched to polymer capacitors with higher ripple ratings to mitigate the problem. • Surge-protected, galvanically isolated DIN-rail power supplies are being evaluated for next-gen in-wall drives, reducing thermal stress. --- Supporting explanations and details • Analogy: Think of the start-up capacitor as the “starter battery” of a car. If that small battery is weak the engine PWM IC cranks but never starts, the dashboard LED just keeps blinking. • ESR rise is exponential with temperature: doubling every 10 K. Cavities behind roller shutters often reach 50 °C in summer; hence premature wear. --- Ethical and legal aspects • Opening and repairing Class I mains equipment voids warranty and must comply with IEC 60335 & VDE 0700. • Provide residual-current protection ≤ 30 mA. • If you are not trained, delegate the repair—electrocution is a real hazard. --- Practical guidelines best practices • Always replace the entire set of electrolytics while the board is out; the incremental cost is < €2 and avoids repeat failures. • Choose capacitors rated 105 °C, low-ESR Panasonic FR, Nichicon PW, United-Chemicon KYB. • Check belt tension and limit switches after re-installation; wrong limits can stall the motor and overheat the driver. --- Possible disclaimers or additional notes • A few units production week 482015 shipped with a defective batch of bridge rectifiers GBU4K; if your board has scorch marks near B1, replacement is mandatory. • LED slow flashing with keypad still responsive is not the same issue—then it is only waiting for end-position programming. --- Suggestions for further research • Evaluate replacing discrete SMPS with a ready-made 5 W encapsulated module – eliminates capacitor ageing at the cost of space. • Investigate retro-fitting BLE or Matter-over-Thread control; the 1550 has unpopulated UART pads. • Long-term: conformal coat boards to fight humidity in exterior walls. --- Brief summary A single dried-out electrolytic in the RolloTron 1550 power supply usually causes the “LED flashes buttons dead” syndrome. Replacing that 10–47 µF, 50 V start-up capacitor and ideally the secondary 5 V filter cap reliably cures the problem. If you are comfortable working on mains electronics, this is a 30-minute, < €5 repair; otherwise opt for professional service or a new drive.

Rademacher RolloTron 1550 Rapid LED Flashing, No Keypad Response – Capacitor Fault Fix

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