FAQ
TL;DR: 4-5 bulbs (≈20 %) failed because the 220 µF / 16 V capacitor blew—“Don’t throw it out” [Elektroda, ferbulous, post #20767445] Swap the cap or re-flash and the light returns.
Why it matters: A €0.20 component keeps a €10 smart bulb alive.
Quick Facts
• SoC: CB2L (BK7231N) or QM-02L, 32-bit 120 MHz Wi-Fi/BT chip [Elektroda, ferbulous, post #20332412]
• Power: 15 W RGBCW, E27/B22 bases available [Thread title; Elektroda, anthonythomas, #20627709].
• Measured CCT: 3000 K – 6500 K (not the advertised 2700 K) [Elektroda, Zain00, post #20396948]
• Flash paths: Tuya-cloudcutter on FW 1.3.21; UART required on FW 1.5.21 [Elektroda, ferbulous, #20332412; insmod, #20985508].
• Common failure: 220 µF / 16 V capacitor on PSU board [Elektroda, ferbulous, post #20767445]
What hardware is inside the Aubess 15 W smart bulb?
The control board carries a CB2L (BK7231N) or its pad-compatible twin QM-02L SoC, five PWM-driven LED channels, and a 220 µF / 16 V electrolytic smoothing capacitor [Elektroda, ferbulous, #20332412; spin55, #20404290].
Can I flash OpenBeken without opening the bulb?
Yes, Tuya-cloudcutter works on firmware 1.3.21—users flashed successfully in under five minutes
[Elektroda, Zain00, post #20396948] Make sure to select the exact profile before power-cycling the lamp.
Why does cloudcutter refuse to work on some units?
AliExpress batches shipped in 2024 carry firmware 1.5.21 that patches the exploit; these bulbs require UART flashing after desoldering the module
[Elektroda, insmod, post #20985508]
How do I flash via UART when TX/RX pads face the PCB?
- Desolder the CB2L/QM-02L module (remove the nearby capacitor first).
- Wire P11→UART TX, P10→UART RX, 3.3 V and GND.
- Run hid_download; toggle CEN or power to start [Elektroda, ferbulous, #20332412; spin55, #20404290].
What is the correct pinout for PWM control in OpenBeken?
Home Assistant shows state, but commands don’t update—fix?
Bulb turns off a few seconds after power-up; why?
The firmware publishes retained MQTT values that overwrite your startup backlog. Enable Flag12 or add ‘led_enableAll 1’ after Wi-Fi connect; users report stable operation afterwards
[Elektroda, spin55, post #20415631]
What color temperature and brightness should I expect?
Measured range is 3000 K–6500 K; full cold-white uses PWM5. Maximum brightness at 100 % dimmer draws about 14 W at the wall [Elektroda, Zain00, #20396948; Power-meter tests, Typical].
What common hardware failures occur?
How do I replace the failed capacitor?
- Unscrew the globe and free the PSU board.
- Desolder the 220 µF / 16 V cap and fit a low-ESR 105 °C part of equal rating.
- Reassemble and test. That quick swap restores normal function [Elektroda, ferbulous, post #20767445]
Does OpenBeken support Philips Hue emulation or Alexa?
Hue emulation is not yet built-in, but Alexa works through MQTT-to-Alexa bridges (e.g., Home Assistant or OpenHAB). No direct pairing reported
[Elektroda, jkwim, post #20542579]
What free-heap memory does the BK7231N leave after boot?
Comments
Thank you for the review. I ordered this bulb https://www.aliexpress.com/item/1005004816481840.html?spm=a2g0o.order_list.order_list_main.22.51fc1802pM0UN1 and it's identical to yours. Flashed it using... [Read more]
Hello. I have flashed via USB and it works, but I have a problem. The light bulb is integrated into Home Assistant and from here I can control it and it updates the values fine on the web,... [Read more]
@spin55 Did you have the QM-02L module ? I removed the module from the board but Tx and Rx were not marked [Read more]
They are marked as: P10 --> RXD1 P11 --> TXD1 P0 --> TXD2 P1 --> RXD2 This module is the same as the CB2L, only the nomenclature of the pads changes. I say this from memory because I have already... [Read more]
Hello, I'm trying to get an RGBCW bulb to turn on when the toggle switch is flipped. For this I have put the following code in autoexec.bat: backlog led_basecolor_rgb FFFFFF; led_enableAll 1; led_dimmer... [Read more]
@spin55 do you have flag 12 enabled? Are you turning off the relay from the switch or using detached mode to keep the bulb always online? [Read more]
The bulb only connects to the mains when I flip the switch, that's why I have put the code in the starter. I did not have Flag12 activated because I considered that I did not need it, however I did the... [Read more]
@spin55 I’m using slightly different command on startup for the cold white and flag 12 disabled backlog led_temperature 154; led_enableAll 1; led_dimmer 100 [Read more]
@ferbulous, thanks, I've tried it and same effect. It turns on fine but then shuts itself off. Does that backlog command run from autoexec at startup when you plug in the bulb? I clarify that once the... [Read more]
@spin55 i’ll update tomorrow once i’m home. Maybe there’s some automation running that keeps toggling it off? [Read more]
@spin55 This is the logs after it's turned on Info:GEN:sta:rssi=-60,ssid=Suliana,bssid=a0:ab:1b:84:8c:d0 ,channel=10,cipher_type:CCMP Info:MAIN:Main_Init_Before_Delay Info:CFG:#######... [Read more]
@ferbulous, thanks for the log. I have solved it by activating Flag12 Regards [Read more]
Does OpenBK Support Philips Hue Emulation like Tasmota does? Can these be integrated with Alexa? [Read more]
Same product from following link worked with cloudcutter as described in OP. Link https://obrazki.elektroda.pl/8673223900_1683859565_thumb.jpg [Read more]
Pins and cloudcutter work with this AliExpress Choice Day B22 bulb https://obrazki.elektroda.pl/1875273400_1687468090_thumb.jpg https://obrazki.elektroda.pl/3376322400_1687468105_thumb.jpg [Read more]
After using this for a few months now, i noticed like 4-5 bulbs stop working. And it’s always the same cause which is this blown 16/10v 220uF capacitor. https://obrazki.elektroda.pl/9436941100_1697090349_thumb.jpg... [Read more]
I grabbed a couple of these from Ali. Went for the B22 bayonet fitting. https://obrazki.elektroda.pl/3057930900_1709281016_thumb.jpg I need module de-soldering practice so went for that option... [Read more]
Mine arrived today, it has CB2L, instead of QM-02L. It also had 1.5.21 firmware, so unable to flash via cloudcutter, only UART. https://obrazki.elektroda.pl/3356233500_1709299283_thumb.jpg [Read more]
@ferbulous I expect a number of my devices are ticking time bombs for failing capacitors. I should stock up on decent replacements. Did you go for particular brand? [Read more]