The newer LED controllers for LED Christmas lights use alternating polarity to drive two channels of LED lights. This means it's not possible to bypass the controller internally to stop the lights flashing.
When you realise why these controllers don't store their last setting it is quite annoying. It's merely the omission of a single cheap memory chip from the controller, which does have a space for it. On many sets the memory function is in place, so this is clearly an optional "value added feature".
Putting the chip in does require quite destructive opening of the case and the soldering in of a tiny surface mount memory chip. This makes it a project best suited to the electronically inclined.
The chip required is a 24C02B although I used a 24C02N. It's a very common low level EEPROM memory chip.
When you realise why these controllers don't store their last setting it is quite annoying. It's merely the omission of a single cheap memory chip from the controller, which does have a space for it. On many sets the memory function is in place, so this is clearly an optional "value added feature".
Putting the chip in does require quite destructive opening of the case and the soldering in of a tiny surface mount memory chip. This makes it a project best suited to the electronically inclined.
The chip required is a 24C02B although I used a 24C02N. It's a very common low level EEPROM memory chip.
I got really excited when i saw your video as the pcb looked almost identical to mine.
But to my dismay mine is slightly different and doesn't have the provision for the memory ic so i think im a little out of luck 😢😢
Also reading through comments i will say mines a 31v 193ma 6v power supply.
I have a board number on mine gp-sw060d1-t. But thats all i know. Llease help clive its the one set of all my lights that dont have memory…
I have the same set but mine has a function controller between the lights and power supply. I'm trying to figure out how I can cut the line in half to create two identical sets. The back half of the line won't work. The first 10+/- lights are flashing but the rest are out. Any ideas how I can get this working?
Hi Clive thanks for the explanation of how these 2 wire LED sets work. I have a set that I put up last year and the section closest to the controller has failed. I dont understand how the whole section could have failed to light when all the LEDs are connected to the same bus. Any ideas?
Just bought some lights… mine has a MLS-D12V6BWCX-IP44 controller and annoyingly doesn't remember its setting and the default mode is very annoying. Haven't got the nerve yet to take it apart.
In September 2023 I have purchased a string of 100 warm white lights in a Wilko sale. It has a battery powered control box with a few sequences and a 8 hour on, 16 hour off timer. I opened it up to see if I could fit a memory chip, but everything is done with an 8 pin chip and a tiny crystal. The chip is the microcontroller and H bridge all in one. Great fun and all for £3.00!
Hi Clive, I'm guessing there's no easy way to rewire these to work with a straight DC power supply? Going off of your diagram, I'd need to go through and flip every second LED on the string to get them all to light.
Would the 24C02B work? I am looking at the 24C02C-I/MS MSOP. Is MSOP also the correct chip type? I ordered one already and it was WAY too small and for super small surface mount stuff.
Or one could use a relay to disconnect the light string from the controller, and simply leave the controller powered up… 😜
With out reading through all the comments to check if I’m doubling up.
My understanding of the change in polarity is to facilitate the patterns/flashing while only using two wires instead of 3.
Great explanation and I’ll give it a try.
Thanks.
Finally got around to installing this chip. Brilliant, now I have my outside lights on a timer and no need to mess around with the mode button. Thanks Clive.
Hey there! Not really hoping anyone would see this message, but still worth a try.
I have LED christmas lights with a slightly different controller: it is smaller, roughly thumb size, and it has SMD components.
There are two chips, one labeled IC8301, and the other without any markings,
but it does not store the last used setting in the memory, so you have to do the hated 7 button presses to get to the steady light mode.
There is no place on the PCB to try adding any EEPROM chip, and it's too different from the older designs where it's obvious which contacts should be bridged to stop it from flashing.
Is there any chance to fix this?
How can I do this without a memory chip? My lights look really similar and I just want to short something as simply as possible without installing a mem chip, it's not like I'll ever use the spastic modes.
I'm still puzzled about how 2 wires can control all those modes. Anyone suggest an explanatory link…? Thanks.
Great video. Exactly what I am trying to resolve. Question: where should the memory chip be installed (sorry I am not an electronics expert)?
What a brilliant video. Informative and well-delivered. I can’t believe that there isn’t more material out there on such an annoying problem with these lights.
Off to hone some soldering skills…….
I have two sets of 50m lights that use these power supplies. I've been looking at getting a dimmer for the lights, as it appears the circuit itself is capable of dimming during a slow flash pattern. However nothing is available. I'm wondering if it's feasible to customise the controller to "fix" the dim on a preset at say, 50% brightness?
I had several sets of lights with no memory that were for a large tree in my garden. To open all the controllers and doctor them would have been a tedious process so I made a new power supply that could run all the light sets. A single plug and timer in my garage was far better and the lights appeared to run continuously as I wanted. Basically I used a 24V transformer (which incidentally came from an old set of incandescent lights) and full wave rectifier with smoothing capacitor to give about 33 volts. A 5V regulator and astable multivibrator generated an output of about 15kHz which operated an H bridge to give a square wave alternating current of sufficient power. A very satisfactory outcome for me.
An interesting comment about minimising corrosion by using ac. Personally I think it is more about manufacturing costs. Using ac needs only two wires whereas dc would need three. This obviously saves money for the producers as does omitting the memory chip. These small savings mount up when you consider the quantity they produce. Why would they want to increase the life expectancy of the lights and thereby potentially reduce their future sales? Everything is driven by money and not concern for the environment with these big companies!