I just bought a 101 credit visa platinum dump from joker, and when I went to use it, it asked for a PIN, with no option to not enter it. I did use a self-checkout at a major US retailer, is that the issue? Can you not use dumps on self-checkouts? If that's not the issue, then what is?

Some cards still have pin protection on it. For example before there was 201 Debit cards still had pins. Also some of the new POS terminals ask for Pins even if the card doesnt have one, for example anywhere you go in europe any self check out POS will ask for a pin

what bank bin u using? only problem i had at a pos with credit is 3 digit pin which is the cvv