I bought 20 of these CH224K-based USB-C PD boards from aliexpress and, as far as I can tell, they don't work.
I hook them up to a USB-PD supply, with a cable that works with 20V on my pinecil, and D1 blinks on and off at about 3Hz. I get 1-3v on the output regardless of the setting. I've tried four different USB-PD AC adaptors and an anker battery bank. The only time I got a different result was connecting it to a non-PD supply and it output 5V, as expected.
Any suggestions?
@tj another cable? Or maybe they only work with a load attached? The other possibility is that they’re fake, but AliExpress is usually pretty good at refunding if things don’t work.
@jpm I tried a few cables. I just hooked up a 20V load and an o'scope. The voltage spikes to 5v every 200ms regardless of the DIP switch setting.
@tj bizarre, just a simple resistive load eg 500-2k ohms?
@jpm Nah it was a DIN-mount industrial network switch I had within reach.
@tj I’ve seen switching power supplies do weird things with approximately zero load, including failing to start. This also smells a bit like over-current protection, possibly triggered by startup inrush. Try a simple resistive load, 10-100mA usually provides enough to get things moving. If that fails, then yeah, almost certainly you’ve got duds.
