Logic Board Replacement and Software Myth
There are people who replace the disk's logic board with an equal one from a hard drive that's working in order to try to revive a dead one.
This is the most sensible myth. The replacement of the logic board works in some cases where the damage is external and the firmware is all concentrated in the controller. So it's worth trying, and if you do that carefully there's chance of saving the data.
However, if the drive is recognized but the read is not successful, avoid the other myths described here and send your hard disk drive to a specialized service, in case your data is really important.
The Software Myth
Some data recovery software certainly work when we have a pure logical problem. The problem is to use them when the disk shows some kind of physical problem. In this case, the software automatically sweeps the drive and once more the worse can happen: the last chances of recovery without having to open the disk go down the drain, since some circuits stop working during an automatic recovery of this kind. Therefore you need to know when to use this feature.