Here's the situation. A seagate 80gb harddrive was shorted out so badly one diode was blown off the board and you can see a burnt spot on one of the other computer chips. The harddrive was no longer being recognized and would not spin. I purchased a donor drive with a very close date code. I swithced the pcb's and it still was not recognized but it now spins and you can hear the head searching by the clicks it is making but it still is not recognized. I've taken it to a data recovery company and they say it needs the head unit changed and it would be very expensive. Now here is my question, is the donor pcb still good or do I need to purchase another one to change it out when I change out the head unit?
Thanks,
LeRoy

You are going to change the head unit yourself?

Very tricky job, even for professionals. If you really need your data, then pay the DR company to do it. If you try and mess it up, chances are your data is gone for good

Thanks for the advice, my question is this, is the donor pcb still good or does it need to be replaced also when the head unit is changed out?

If the PCB still spins the drive up, it's probably not damaged, so should still be functional.

But whether or not it will work with your drive is a different matter entirely!

There are a number of things you need to check from the patient drive:

1. Model (obviously!)
2. Part number of HDA (e.g. 9T6006-040)
3. Part number of PCB (e.g. 14853 E)
4. Firmware of HDA (e.g. 5.05)
5. PROM code of the main chip on the PCB (e.g. 102078-503)

Hope this helps, and good luck!