Reviving a 1970’s Hard Drive for the Mini Centurion!

I found a drive similar to this one STILL RUNNING in a rack at an AT&T wire center. I'm sure it hasn't done anything useful in 40 years, but if you've ever worked at/with AT&T, you'll understand why it's still there. "Not mine. I don't know what it does. I don't want to be responsible for what happens if it doesn't do that anymore. Just build a new rack beside it and leave it alone."

I see a lot of older people here talking about their experiences with these computers, and that's awesome :3 I'm a gen z (20 years old) but find older tech like this really cool, especially love the big bulky monitor aesthetic, always glad to see people making efforts to preserve tech history ^w^

David, that head retract gave me a PTSD! So did reusing that filter! But I do understand... The Hawk drives are very forgiving. We would go in for a preventative maintenance and find a scuffed platter that was still working perfectly. The customer was able to back up what they needed, generally on floppy, and we'd replace the platter and heads. Phenix drives aren't so forgiving! I believe the base configuration was a 2.5 meg fixed config without the removable. Not sure if that had a different bowl or some kind of insert. By the late 80s the hawk based systems were end of life, so if the customer was running out of space, we'd flip the switches and give them the whole 10 meg. Remember, back in those days 10 meg was a lot of floppies! We worked on a lot of systems that didn't have hard drives. So having 10 meg was awesome! Seems like 8 inch floppies were about 160 k! Hooking up an Oscope would have been a good idea on your alignments. It would help to see the maximum signal. And cool to look at! We used to align drives to a customer's pack when the drive wasn't properly aligned before a crash. Of course we'd align it properly after the data was backed up. You need a Kennedy tape drive! Still my favorite thing I've worked on! Great video! Thanks!

This brings back lots of nightmare memories. In the early 1980's, we paired the CDC Hawk drives with either a Texas Instruments Ti/99/10 or a Ti/99/10A CPU. Being forced to run one of these drives on an active construction site with lots of drywall dust was a challenge. I got really good using a small microscope to re-polish crashed heads and a CE Pack to realign the heads. At that time, new heads were $750 a pop, so there was a bit of an incentive to refurbish heads whenever possible.

I like their miniaturization. I bet one could store a lot of song lyrics on it for their Centurion pod. Imagine rollerblading down by the beach, with your mini centurion in tow, with a battery powered terminal, reading off all of the era's best song lyrics. 😅😊

11:13 The LM339 is not an OPAMP but a comparator with open collector output. Connecting the outputs together forms a so-called "wired and". The output is high if and only if all four conditions are met (= all outputs are high). It any of the comparators is low, it's output transistor pulls the signal low.

I remember seeing my first 10mb hawk drive and thinking, it’s insane how could you ever create 10mb of data without backing up everything 100times. I remember also looking at the ibm 360k floppy disk and wondering what would you be doing moving that much data. How things have changed

This episode means so much to me man. This is exactly what my dad used to do at his first job. He'd go on service calls and repair/align disk drives, although I believe they were something more like IBM 1311s. Originally an electrical engineer, taught himself to program and followed that path. Still bummed he got rid of his SWTPC 6800 sometime in the early 00s. But his working TRS-80 sits behind me as I work in my office. Thank you for all that you do.

A trip back to the good old days of field service, I used to fix those in the early 80's, particularly the Hawks and Tridents, my workmate left his pack of cigarettes inside the cabinet under the Hawk used by ERNIE (the random number generator used by the premium bond system), he wasn't a happy camper that day as we had a tight window to perform a PM - fortunately they were still there when we did the next PM a year later.

There may be more issues with that burnt-up SCR. It's supposed to be, I think, a crowbar circuit to trip the breaker if the regulator voltage gets too high. It's supposed to only conduct for like a tenth of a second until the circuit-breaker trips. I used a circuit like that around 1968 but with a 1 ohm current-limiting 1/4 watt resistor in series with the SCR. When I tested it, the resistor exploded and sent resistor shrapnel all over, including near my eyes! But in your example there seems to be a different problem-- the area is so charred up, one might deduce that the breaker did not trip quickly enough or maybe not ever. So I'd probably test or just replace the associated circuit breaker. It's always something!

That entire hard drive it too small to contain a single Amazon webpage.

In age of a punch cards - 10 MegaBytes? -_-... For REAL???!!! GIMME TWO!!! But how damn expensive these were...

Hi, David! Сarbonized textolite conducts electric current. Before installing a new thyristor, it is worth cleaning off the burnt layer between the board tracks. Otherwise, an unpleasant surprise may occur.

Great episode. I was surprised you didn't check the rubber bumper from the first. You might put that on your checklist. All the drives you work on after sitting for 40 years will need new bumpers.

I remember scrapping one and kept the huge powerful magnets !

I would consider a heat sink for that replacement part you soldered in.

This reminds me of the NCR 8250 mini computer, my wife worked on. She did the data enter for a accounting office on a terminal similar to those. She could key very fast an accurately it amazed me. When they switched to micros in mid eighties we got the old computer and drives and discs to play with. My buddy still uses the cabinet in his shop got a mig welder in it, slides out nicely lol.

I loved the take before the intro rolled xD "RIGHTTTT?!!!"

Brake bleeder dust covers would be perfect for bumpers

It's crazy to think that just over 10 years later, the IBM Type 1 MFM hard disk would come out in full height 5.25 inch size, weighing about 10 lbs with a capacity of 10 Mb. I had one somewhat recently in a 286.