Hi - I'd like to describe several HDD cases and get expert opinions on how to approach the HDD problems. I think this will be good for the newbies like me to see how to solve HDD problems. For each HDD problem, how would you fix it and what tools would you use?

Hitachi laptop: HTS541080G9AT00
- Loud clicking
- Not recognized by Windows, Linux, BIOS or MHDD
- What would you do? Replace PCB? Replace heads/pre-amp?

Seagate laptop: ST910021AS
- Recognizes OK
- Begins sector-by-sector copy stops after 30 seconds(device errors)
- What would you do? replace PCB? Replace Heads/pre-amp? Connect to COM device to issue terminal commands?

Hitachi laptop: HTS541210H9AT00
- Clicking/Scraping
- Not recognized by Windows, Linux, BIOS or MHDD
- What would you do? Replace PCB? Replace heads/pre-amp?

Seagate desktop: ST3160828AS
- Steady quiet clicking
- Not recognized by Windows, Linux, BIOS or MHDD
- What would you do? replace PCB? Replace Heads/pre-amp? Connect to COM device to issue terminal commands?


I think there is some confusion about when to repair firmware and when to replace parts.

Thanks for any and all comments. Please take your time to answer - longer answers are better.

A

All those clicking are usually head problems.
Before doing head swaps though, I would open the drive first to check that there is no platter damage. Then I usually try compatible PCB (certain rules on apply) and hot swap after donor comes in. If nothing helps and platters are fine it's time for a head swap.
In some cases instead of doing full head swap I would try to clean the heads first or replace just the preamp.

As for Seagate laptop: ST910021AS, it probably has non-system head bad. I would try to jump around the surface to locate the pattern.