When charging my Hisense Sero8 tablet, with the wall charger, it will only show charging as USB, not AC. Charge times are from 6 to 8 hours, using the supplied charger. (Charger and cable are both good. Other devices charge properly.) My questions are; 1 - Is there a way to reset the charging system, so that it will recognize the AC charger? (Hopefully without doing a full factory reset.) 2- Would a charge-only cable be worth the investment?