hi all!
HDD is spinning up, then do some head clicking and spindown. after spindown i can read ROM information such as ROM version, head map, etc. so i think the problem is at preamp or heads/comms part. is there any technique to check pream, other than swap PCB (i dont have same HDD right now)? or can i, for example, filter data channel on some test point on PCB to get HDD to initialize properly?

PS we have legal PC3k and almost any soldering equipment, sorry for english, its not my native lang

Then ask support.

You never can make any hdd to initialize properly if any read channel is shorted or filtered!
The only what you can get is a mode, special mode for repairing.

Janos

IMHO AceLab (PC3k developers) has a very poor support and documentation, almost nothing changes in this aspect since 1998
so the only way for me is good old hotswap (with ROM reprogramming)?