Review on 🔌 DAOKI 5 PCS AC DC Power Supply Buck Converter: Step Down Module 12v 5v 3.3v 9v - Efficient Voltage Conversion Solution by Mark Greenwood

I received the 9V version which worked best for my application. I needed 9 in total and I figured two packs of 5 would give me 9 and a spare. but . two were DOA and one broke down after just a few weeks of use, even with light use, so I had to order a few more packs to make it last. In my 40+ years of working with electronics I have never encountered a solder as bad as on these boards and I don't just mean the quality of their soldering but the actual chemistry of the solder itself. It must be an experimental solder paste they are using in the reflow process or something but it won't flow and connect like it should. And I think most of the bugs that people report are due to cold solder joints. Even soldering wires for I/O connections to the board was annoyingly difficult. It's as if the solder has a waxy base that needs to be heated sufficiently to burn off before the solder actually begins to flow and adhere to the metal as intended. I recommend touching up any solder joints, especially the thru-hole components, and looking out for any random drips of solder they may have left behind and removing them. I found a few loose solder blobs on the boards I received just waiting to short out something on the board if left there. Your source is a few hundred milliamps. When they failed, the output voltage usually dropped to about half that value - at least that's why two of them failed. And one just drifted with an unstable output. It was still trying to output 9V, only drifting 9V instead of maintaining a stable output voltage. They worked for my application and I have yet to find another inexpensive alternative that is better. If you do get them, be sure to buy plenty of spares and test them out before permanently hooking them up to anything, and try to keep an eye on a future replacement in case it dies on you. They slide well into the 1" (25mm) heat shrink tubing which acts as a good insulator making it easy to replace if it dies.