Hi -- I'm in the market for a very budget PSU and was considering a used Korad. I've seen Dave's video (youtube ?v=Fya-4mjV4N4), and I know that they fixed the issue (youtube ?v=_HrvuHSywms) he found in his video many years ago.
When shopping for a used PSU, is there any way to tell if it is manufactured after this fix was deployed? E.g. via serial number or other tells?
E.g. the one in Dave's video has no input AC selection switch (120/240) and later models do, but I don't know if that's reliable.
The serial numbers I see out there are all over the place, but I'd assume "higher = better".
Any other indications? Thanks!