Recharge Coby 707 mp3 player. Can I use recharger wall adapter input 90v-240v output dc 4v-8v? Is there a limit how log it can be recharged?

If you use a recharger other than the original, make sure that the voltage and polarity of unit is the same to one being replaced. Try to use one with a similar amperage as the original. Look for amperage rating of your batteries and then divide that by the amperage out on your charger to determine a safe charge time since you do not know if the replacement charger has an auto shut off - u do not want to overcharge the batteries and damage them.