Tony Duell wrote: Thing is, the electronics of the older drives uses simpler ICs, and fewer custom parts. I would much rather repair an ST412 (for which I have schematics anyway) than the IDE thing I've just looked at. ----------------------------------------------------- Billy: I've data from 3 different disk drive companies over 20 years and 100+ million failed drives, that show the same thing: PCB failures are less than 1% of the total field return failures. The vast majority are tribology related (heads and media). I know a few specialty companies that can recover data from crashed drives. But I know of none that try to repair crashes. The cost is hundreds of times greater than buying a new disk. ------------------------------------------------------ wear > out and ferrite heads and oxide media are gone. Occasional bits and True. But other problems inside the HDA would be much easier to repair on an older drive with a much larger head flying height. I think it would be possible to make a 'clean box' to open up ST412s at home and repair them and expect the repaired HDA to be reliable enough to use. That is not the case with modern drives. ------------------------------------------------------- Billy: I'm not certain what you think can be repaired in an old ST412. I know you can't make the media or rewind the heads, so I assume you are only talking of substituting parts from another unit. Which may be in just as bad condition. And even if you could put a new platter in, how do you do servo track writing? Disk drives are not designed for decades of life. They're designed to last until the next new tech is available - cheaper and faster. Their design, whatever era, is at the bleeding edge of available technology at time of design. Technology pushes with each generation. Your ST412 was designed for a range of 40-60K hours MTBF. Current products are at 1.8M hours. A lot of that improvement comes from getting rid of the individual components, solder joints, power consumption electronics, connectors, etc. So you can find the odd ST412 that you recover. But is it fun? Is it worth the time you spend vs buying a ?20 IDE drive and having time to use your system? I know we share a love of understandable electronics and hands on computing. And especially building our own design out of logic. But repairing old disks because you do not want to learn new technology seems to me to be counter-productive. I must admit that I truly don't understand your logic in only using devices that you can troubleshoot down to the electronic component. (It reminds me of a few classic stories of Victorian handymen who shared that philosophy dealing with the first electric lamps .) It seems to me that you are severely limiting your fun by ignoring all the new technology that is out there. The world has moved on. Today, we often have to work with conponents that we can't repair - such as a processor chip with 100 million transistors. Perhaps this is where we differ. You want to work only on products that you understand each component and can fix. I want to play with it all - even if I can't get into all the minute details such as firmware, ASICs, or FPGAs. Maybe I can't repair a Pentium chip. But I can make it sit up and do tricks. And by doing so, improve my marketable skills. I was hired for my current job at age 63 - primarily because of my knowledge of the latest technology; not the 35+ years experience on old drives and dinosaur systems. Billy