Hello there everyone!

My name is Ty, and I'm brand new to the forums. I read through the "please read before posting" document, so I hope this post is acceptable.

I'm coming here because I've been having some real difficulties reproducing two electronics projects seen in Youtube videos. There are two projects with two separate issues, but instead of flooding the forums with multiple posts, I've combined them both here:

Project 1: Sun Blaster (As Per

)

I don't expect people here to actually watch through the videos so I'll try my best to summarize. This project exists to power a 100W LED chip with voltage-based dimming. It uses a 120W laptop AC-DC power adapter as the input, and it feeds it into a DC-DC Boost converter rated to 150W (as per THIS) The board's trim potentiometer was extended and connected to a 10K linear potentiometer (CLICK) to create the dimming control, and then the board outputs to the LED chip (CLICK).

I built the thing, and amazingly, it worked. Problem was, when i jiggled the wires leading to the voltage dimming array, the light would rapidly hop between full brightness and whatever brightness the nob was set to. I figured out that one of the connections was faulty and was leading to 0 resistance, so i cut the voltage dimmer wires off, and remade it from scratch.

I've now remade the voltage dimming system like 6 times... and the light won't work. The board is now outputing 37.5 volts as a minimum, which is far above the LED's maximum 32 volts. When i made the system the first time, the minimum was around 24, and by varying the trimpot, i could get it to climb to 30V. Now, the lowest I can get is 37.5, and if i vary the trimpot it only goes up from there. What's more, the knob potentiometer doesn't affect the output voltage at all, and I feel like that's where the problem is.

I have two linear knob potentiometers, and I've tried using them both, but they don't seem to be affecting the output voltage. What's more, i can't measure a resistance value at all using my multimeter. Like, there's just no reading (and yes, the meter works, i tested it on some standard resistors of known value). I'm wondering, did I burn out the linear potentiometers with too much heat while soldering? I'm using a Hakko fx 888D set to 800, so it's definitely possible I suppose.....

For a circuit diagram of the voltage dimming setup, go to 4:04 in the video




Project 2: Sun Blaster 2.0 (As per

)

Okay so, second attempt at a upgraded version of project 1. Im using the same laptop power adapter (which btw is working perfectly, i've tested it), and this time I'm inputting to a beefier DC-DC boost converer (CLICK) before outputting to the LED chip. Once again, the trimpot on the board is expanded into a voltage dimmer by adding a second trimpot and a linear knob potentiometer. I set everything up as per the video, and it worked, though somewhat differently from how he had it work in the video. I set the current limit to 3A as per the video, and right as I was reaching for the other trimpots to adjust the dimmer settings, the whole thing died and I started to smell the magic smoke so i unplugged it.

For a circuit diagram of the voltage dimming setup, go to 4:42 in the video

Long story short, whenever I connect the power supply to the DC-DC boost converter board, even with NOTHING attached to the output, and even with No completed circuit on the output, the NCE6075K Mosfet overheats and practically de-solders itself within 2 seconds. The board's outputs read only 2 volts, despite an input of 12v and the fact that its a BOOST board.

I have one more boost board i could use, but i don't want to burn it out as well..




I'm really starting to feel defeated because these videos make it look so easy and Im following them to the letter. I've checked my wiring like 10^23 times and everything is good, and my solder connections are clean and shiny. I just don't get it.

Any help is really appreciated, thank you all.
-Ty

 

EXTRA INFO:

Here's an image of the voltage dimmer circuit from Project 1:




And an image of all of project 2 is attached (couldn't include it in-line for some reason). The red clip is pointing to the overheating MOSFET

 

Any help or suggestions would be greatly appreciated.

 

I don't see a massive liquid cooled heat sink like in the video.

Bob

 

I don't see a massive liquid cooled heat sink like in the video.

Bob

The large metallic finned things are the heatsinks... they're right there in the images. The LED chips haven't burnt out or overheated, that's not the issue. The LED's are actually being undervolted so they run pretty cool as it is. By merely having them attached to a heatsink at all, heating problems are eliminated.

 

Any help or suggestions would be greatly appreciated.

You need to start by providing a schematic.

 

If something flashes or dims when you jiggle it, you have a poorly soldered connection or you are creating a short because you have exposed wires (use heat shrink tubing and properly brace all components from wiggling). Also fat wires are difficult to solder unless you have a proper soldering iron.

 

If something flashes or dims when you jiggle it, you have a poorly soldered connection or you are creating a short because you have exposed wires (use heat shrink tubing and properly brace all components from wiggling). Also fat wires are difficult to solder unless you have a proper soldering iron.

I don't think its an issue of connection quality though; Im using a Hakko fx888D soldering station set to 800F. I'm applying rosin flux to all of the joints, and I'm feeding solder into the heated wire, not just putting a blob on the tip of the iron and trying to solder that way. The solder joints are coming out shiny, cohesive, and smooth, and all of my connections are fully insulated with heatshrink tubing (as you can see in both of the pictures I uploaded)

That being said, I'm using cheap chinese potentiometers, and the flickering happened when i jiggled the leads coming off the Pots, not the wires. I have a feeling it might by shitty potentiometers that got burnt out somehow, because I just tried to pass some current through them with a battery, and I'm getting no current whatsoever through the pots, but i do get some through brand new pots that I havent used yet.