The location of the burnt resistor could be R2 or R3. The black smoke is covering the printed number.

Schematics for the item, or looking at another working identical item are the only two ways I know of.

Word of note... resisters don't just burn up for no reason. Something else failed and that was the weak link when the extra current started flowing. You have to find and fix that as well. Replacing the resister alone won't fix the real problem. Next time it may end up beyond repair otherwise.

That model gets 2.5/5 stars rating and is obsolete. Is it really worth fixing?
$6-12 on eBay, some with free shipping.