WMYCONGCONG 5 PCS MT3608 DC-DC Voltage Regulator Step-Up Boost Converter Power Supply Board 2V-24V to 5V-28V 2A with Micro USB

I bought these just needing one to convert an RC radio 4 AA to Lipo 3.7v. I soldered everything up and measured my output. It just had diode drop across it. After some research, I found that you have to turn the adjusting screw at lease 15 times (clockwise) before you can see deflection in voltage. They work great!

I didn't use these right away so I was unable to return but out of 10 pcs, 3 were bad out of the bag, 3 had almost no adjustment - went from 0 to supply in less than 1/4 turn on a multi turn pot and remained unstable and unusable, 2 worked for a short time at less than 1/2 rated current (used to reduce 12v supply to 5v level for use on Atmel nano circuit) and just this am 1 actually burst into flames with a 12v supply and only a voltmeter as load (setting output/testing). I am on my last one and have very low expectations' - hopefully it lasts long enough to receive my Amazon order of a couple dc-dc converters of another mfg...... Don't buy

I bought this back in 2019 and just tried using them now and realize they are all bad.. all 5. The output voltage is the same as the input voltage and i realize why... there is an error with the PCB where the Out+ should be connected somehow to the wiper of the potentiometer where i do see the correct output voltage but somehow the traces for Out+ was connected to something else... its a while but i deserve a 5 new functional devices because this issue should have been obvious with any quality testing... all 5 have the same pcb error.