[VIDEO] WD1600BB: Can I change U12 with this special head no

[homecomputer]

Hi,
my drive has a fried "SMOOTH" chip. I have tried to change the broken PCB with several PCBs and identical numbers (you know 2060-001266-001) without changing U12 rom chip. The drive is a WD1600BB-22GUA0. Is the DCM and DATE not worse to change such a PCB?

Here are a little video (xvid-compressed) with the sound the drive makes with an PCB (no U12 changed):
http://www.file-upload.net/download-777 ... d.avi.html

Is this sound typical for are false U12 rom chip on the replacement board? The drive is spinning up and down and clicks 1 time between spinning up and down. If yes, what should I respect if I change U12? Is this the one and only thing I must do? I'm not very familiar with soldering (did not often) but I'm handy to repair small things

I would thank a lot if anyone could help me!

Thanks,
homecomputer

[Doomer]

Preamp is dead