Hello, today a short topic. I will present here another CCT lamp, this time with a rather hard-to-reach WiFi module, the firmware change of which requires desoldering the 2x5 pin connector. I will also show here my method of desoldering this connector. After changing the firmware, solder the connector into place. All in order to free this lamp from the manufacturer's servers.
NOTE: There was already a YouTube video on the forum about the firmware update
ceiling on CB2S , and there was a presentation of the interior of the plafond on
MXCHIP EMW3072 . Here, another, third plafond will be presented, also quite popular in Polish stores.
The lamp was bought in a Polish mail order store for about PLN 80. In this case, only white temperatures (cool and warm) were needed, so the CCT model was chosen, without RGB.
The product model is KSMN18CTWA. The product is distinguished by the characteristic quadrangular distribution of LEDs:
The packaging in fact:
Instruction:
Pretty much everything is standard here.
Mounting pins are also included:
We look inside... The cover is simply twisted to the side and ready to be removed. Then you can see the controller and LEDs:
And the LED power supply - even with information about power consumption and LED supply voltage (120V DC 150mA):
The inside/power supply of the controller? You can already see the PCB with the WiFi module, but inverted...
Unfortunately, these goldpins are soldered on both sides. The module cannot be removed without soldering.
By the way, you can pay attention to the fuse resistor, varistor, quite a large number of transformers/filters (separate power supply for WiFi and LEDs?), AXBOOM capacitors (this name does not bode well?) and the BP2525 chip (mini converter giving 5V at the output):
Bottom of the PCB... here you can unsolder the WiFi module:
I decided on the method of flux + lead binder + uniform heating of all solders:
There were no problems. The pads are not damaged, everything is fine:
You can see that the WB3L module is used here:
Pinout (bottom view):
Let's take a look at the now exposed parts of the main PCB:
The BP2956 is a constant current LED controller with the brightness level controlled by PWM. It connects directly to the mains, it is basically a step down converter:
This arrangement is present on the PCB in two pieces. This is why elements seem to repeat themselves. We have two separate LED circuits here, for warm and cool white.
Firmware change... It's a regular BK7231T, so either bkWriter 1.60 or my Gui Flasher:
https://github.com/openshwprojects/BK7231GUIFlashTool We only connect RX, TX, GND, 3.3V and when the program is waiting for "getting bus" we turn off the power for a moment.
Connecting the wires should be simple:
Then you have to solder everything in place ... here are the next stages, pins in their places:
Soldering:
Cleaned PCB:
The question remains which PWM is from which color?
- Cool Warm - pin 7 (PWM 1 - in OpenBeken set channel 1)
- White Warm - pin 6 (PWM 0 - in OpenBeken set channel 2)
NOTE: It may be the same device as here:
[BK7231T/WB2S] Smart Led Moon 18W 1260lm CCT Summary Programming this lamp was easy and pleasant for me, but I realize that not everyone can solder the module as well as me. After all, I think that the flux and lead binder work wonders and you can desolder such a module on the 2x5 connector easily and pleasantly without damaging the tracks. It is a pity that this connector on both sides was soldered, if it was removable, it would not be a problem.
The lamp is generally very nice, but quite dark, but what can you expect from 18W?
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