USB to Serial Adapter 3.3V output

We’ve purchased 75 of the USB to serial adapter boards recently. After using about 30 or so, we’ve found 3 or 4 that don’t output anything on the 3.3V terminal of the board. What could be some possible reasons for this?



I have not heard of this problem before. Are the affected boards completely non-functional?

- Ben


Thanks for the reply. I’m not sure, let me do some testing. We’ve found several more boards that aren’t working.