Evan wrote: > It's my impression that design features such as soldering the controller > under the mech are considered good practice from a DESIGN FOR > MANUFACTURABILITY point of view. And I'll bet that whomever came up with > that wonderful idea got a bonus for reducing manufacturing costs. It's probably more likely that they did this because it improves the reliability of the disk. HP learned long ago that if you solder memory chips in, rather than putting them in sockets, that the increase in reliability more than outweighs the requirement that the whole board be replaced if a single RAM chip fails. The problem with using this logic to justify soldering the controller to the disk drive is that while it probably improves the overall reliability of the drive, it actually *increases* the catastrophic failure rate, by guaranteeing that every drive failure is essentally a "mech" failure which requires the replacement of the part of the drive containing the user's data. As far as I know, HP does not inventory drive mechs and controllers separately in the field. When a failure of a controller occurs, the CE will swap the controller from the replacement drive with that of the failed drive and then send the whole unit back for repair. So HP gets back the same number of failed drives regardless of the type of failure. If the soldered drive<->controller connection improves the overall reliability of the drive just a little bit, they will get back a smaller number of drives, making the soldering decision look like a success. Unfortunately, the number of disk failures that cause the loss of data may *double* from the customer's point of view (it could be worse than this because I hear about more controller failures than mech failures usually). So HP actually sees *fewer* drive failuers, whereas the customer perceives *more* (catastrophic) drive failures. A quite interesting quality problem. :-) G.