Repairing a legacy system can be quite a challenge even with the right parts and proper documentation, but there are enthusiasts out there who truly dive deep, restoring computers and rare components about which very little is known. One of them is David Lovett, better known as Usagi Electric on YouTube, who decided to take on a CDC Finch 9410 hard disk from 1981, in an attempt to bring it back from the dead…
Storage is an area that has certainly seen advances in the computing world. Not too long ago, 1TB SSDs already cost less than $40 (at the time of writing), and there are fewer and fewer excuses not to upgrade our drives. But there was a time when we were forced to use drives with little space, gigantic in size, noisy, very slow, and extraordinarily expensive. I'm referring to the hard drives of yore, true 'pre-IBM-PC' titans that demanded respect and a lot of patience.
Among them, the CDC Finch 9410 stands out, used by Centurion computers. David Lovett, known as Usagi Electric on YouTube, is without a doubt an expert on Centurion computers, and in addition to sharing his progress restoring those systems, he also published a wiki with more than 70 pages on GitHub. In one of his latest videos, Usagi decided to take on two 9410 units, and try to revive them…
Resurrecting 40-Year-Old Hard Drives
The first drive is not registered by the controller, and the second (which I imagine will have its own video) suffers a short on the 5V line and never turns on. The failure of the first drive was in a SN75110 line driver, and in a 7818 voltage regulator that delivered only 0.3 volts, instead of the 18 indicated by its datasheet. The replacement of the chip allows us to take a look at its PCB, with a truly fabulous design. Usagi's wiki has a high-definition image:
The replacement chip was installed in a socket (always a good idea in these cases), while the regulator gave a bit more of a fight when removing it from the PCB. Usagi spent several minutes on the diagnostics phase, and after getting good results in reading, he connected it to the Centurion operating system. The moment he managed to get a list of the contents is pure ecstasy, and the most interesting thing is that some files have dates from 1996. How does the story end? Actually… it doesn't end, because the drive failed again after 30 minutes. The good news is that the platters and the head appear to be intact, so everything points to another chip on the controller. To be continued…
CDC Finch 9410: Click here
Usagi Electric on YouTube: Click here
