Usually if you swap the original drive with recordings on it, for a new drive, the recorder makes you format the new drive before you can make any new recordings.
Then if you attempt to swap the original drive back in, the recorder does not recognize it and forces you to format the original drive. It also does not recognize the old recordings you know still exist on that drive.
This is a method to do that:
it does not involve yanking molex power connectors
Simply its been discovered the first few sectors of the drive has a type of transaction log. Its unique and incremented as changes are made to the number and condition of the recordings on the current drive.
If you backup the first few sectors of the current drive and restore those to the first few sectors of the drive you want to restore to the recorder. Then the restored drive will be recognized and any existing recordings on the drive will be presented for playback.
If you have lost a current drives transaction log, for example if the drive ceases to work, but you still have an old drive with recordings on it, you should be able to create a new transaction log on a fresh blank drive and back that up. Then restore that transaction log to the older drive with recordings on it.
It is unknown at this time whether drives with recordings can be swapped between two recorders of the same model, or within the same family of recorders. I do not have enough duplicate gear, or samples of gear from the same family to answer those questions. This has only been tested with multiple drives on the same recorder.
I do know things changed a bit beginning with the DMR-EH55, EH75V at that time (I believe) the introduction of TVGOS may have added additional firmware to the drive image (so) this method may be adaptable.