my seagate 1TB plus slim External Hard Drive's head is stuck in park position and wont read the drive.
since 3 months my external hard drive has stopped working so i decided to open it and plug it in my mac and i discovered that the head wouldn't go on the drive to read it! PLEASE HELP!
It is never a good idea to open a hard drive if you aren't equipped with the tools and knowledge to work with what you find, let alone power it on with the cover off outside a clean room environment.
We get these drive very frequently at my lab for recovery. In cases when the drive was not previously opened and DIY recovery attempts made, we are able to save the original heads and recover the data at our base recovery rate somewhere around 80% of the time. After it has been tampered with, 90% of the time we have to change the heads.
If the data on the drive is worth a few hundred bucks to you, seek professional data recovery assistance. Be aware that many labs will charge significantly more after a drive has been previously opened.
As you have already voided your warranty and I can only assume that your data is not worth even the value of the drive, you can try to rotate the platter while carefully sliding the heads back to the parking ramp. But, be aware that a slight fingerprint, a few specs of dust or spatters of spit on the platter will likely be the final nail in the casket. Realistically speaking, you should inspect the heads under a really good microscope to ensure that they are not damaged or covered with microscopic debris. The odds are, the data is lost and you will need to buy a new hard drive.