Hey guys im trying to help a friend out. His 1Tb Caviar Blue isnt spinning up after he said the power to his PC was flicked on and off several times. I just ordered a HDD of the same model and I am planning on doing a PCB swap, I've been reading and have found that I need to also swap the U12 rom chip as well. Then I've also heard that swapping the tvs might be the issue as well. Any help or wisdom is really welcome.

There should be plenty of information about PCB swaps and TVS diodes in the hddguru forums. Search and you will find. These external links might prove useful though:

http://www.donordrives.com/blog/pcbswapguide
http://www.users.on.net/~fzabkar/HDD/TVS_diode_FAQ.html

Diagnose the problem first, then apply repairs. You didn't tell us if the HDD is making any noises when power is applied. Or is it dead silent? "Power flicked on and off several times"... Was this done manually by your friend, or caused by an unstable mains supply?

it doesnt spin but right when I apply power there a 6 ticks in 2 sequences of 3. they are very very quiet that you can't really hear unless your ear is against the hdd.

IMHO your description sounds like stiction (which is not unknown in multiple power-off/on situations) and if that is the case, then a PCB swap won't help. Of course if you have time & money to spend, you can always go through a PCB swap (and associated work) to eliminate that if you want to, but based on your description, I expect you would be wasting your time & money. FYI your description also does not fit with a TVS problem.

If the data on that drive is valuable, then since there are significant risks with trying DIY stiction "fixes", then I suggest your friend has a careful think about the next step - before they ask you to do anything more, which may make later professional recovery more difficult/expensive than it would be now, or even make recovery impossible.

could you explain what stiction is?

also the power was flicked on and off by a switch that the computer was connected to.

Flicking the power switch multiple times most likely made the read/write heads not reach their parking position. Instead they dumped down onto the disk platters, where they are "glued" stuck. Very smooth surfaces tend to adhere (e.g two moist plane glass plates put together).

The disk needs to be opened/repaired in a clean air environment. If unlucky, further complications might involve heads and media damage. If your friend values his data, send the HDD to a data recovery company.

do you have any recommendations for recovery companies that arnt an insane amount of money?

If I was in your situation and in the USA, then I would be talking to guys from this forum like:

jono-ats in Georgia and quasimodo who I think is in Florida (apologies if that's wrong!)

I've linked their profiles to their usernames above, and I think you've now posted enough on the forum to be able to PM them.

There are other forum members in the USA so perhaps they can give you more suggestions, but I know some members don't take direct referrals.