IBM
The Rarest IBM PC Clone in the World!
The Rarest IBM PC Clone in the World!
#Rarest #IBM #Clone #World
“Usagi Electric”
The Centurion is one of my all time favorite minicomputers, but did you know, they also made an IBM PC Clone? Well, they almost …
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18:51 what’s going on with the chips one row up four chips to the right….seems a little too close.. just looks odd , maybe camera angle ?
A rare clone? By definition, it's not
So Computer Controls cloned other machines too? I knew about their Nova clones..
Is nobody else using denture cleaning tablets to clean keycaps? Lukewarm water, add a tablet and the keycaps, leave for 10 minutes or so depending on how funky they are, rinse well then dry. Zero effort. Remove all springs first.
Splendid! 😊
wow
Wow, I had forgotten Procomm Plus. I'm positive I used Procomm, not sure about the plus.
KERMIT.
As a 31-year EDS veteran, this was a great trip down Memory Lane. Actually used one of these for quite a while at EDS. They were actually pretty reliable. Thanks for the deep dive on both the history and the machine itself.
David, words cannot describe how pleased i am that my uncle chose you to become the caretaker and story teller of Centurion Computer. Your excitement and enthusiasm for both the hardware and the people behind the scenes is truely amazing. Thank you for being the man that you are, and continuing share with the world, the time of Centurion Computer.
Looking forward to meeting you someday. 😮
THIIIISS! Is a computer.
At end of video I heard that drive start up and immediately thought it has a stepper motor. And some drives back then were great fun to freakout friends if you put a jumper on the test pins. Made similar knocking-sound as I recall from seeing the after affects of others doing this and so I did a search and not entirely sure if that model can, eitherway don't randomly move jumpers on early rll stepper drives because its easy to wipe them here's the link to the manual (below) which I know David probably already found but for that 1 time just in case.
stason DOT org/TULARC/pc/hard-drives-hdd/seagate/ST238R-33MB-5-25-HH-RLL-ST412 DOT html
I hope you put oil on the reals in those floppy drives😮
They put a lot of engineering effort into a product they had no intention of selling.
@18:'49 it is a quad input AND gate. Pin 1 is the (A) input. Pin 2 is the (B) input for the and gate. Because pin 2 has no power going to it the the output (Y) on pin 3 will always be 0
74LS08 Data Sheet: https://www.ti.com/lit/ds/symlink/sn74ls08.pdf?ts=1715568725995&ref_url=https%253A%252F%252Fen.wikipedia.org%252F
For those who just want to know how this works I'll explain by showing a truth table.
A B Y
H H H
L H L
H L L
In short both A and B MUST be High to produce a High on the output.
The line is a CRT OK test, it bypasses most of the circuits to fire a line to check if the CRT is running and roughly aligned. Tube and early solid state TVs often have a switch that does that marked "test" or "service".
HEADPHONE WARNING for non old-farts: Flyback whine
34:52 – I did this to a Hyperion keyboard – it took 2-3 days…
22:40 – I had a VLB video card with a straight up IDE and FDC controller in it. Great as that PC only had one VESA port.
You had me at "The"
The card on card thing was how you could use the Z height above a PCB to gain more room in a cramped space. It also allows you to have smaller PCB modules that are easier and cheaper to produce in quantity.
20:14 a TI 74LS14 made in Brazil. I didn't know Texas instruments made chips in Brazil.
Nice cats!
🐈🐈⬛
🤘🤘
27:27 "I don't have all the tools that somebody who works on these normally should have"
Most MFM drives will work with RLL controllers just fine. Seagates all worked reliably for years the last time I tried, many, many years ago.
Please make a video about the RLL encoding. It fas cool technology that doubled MFM HDDs size back at the time. Of course there was no standard and every controller had it's own encoding. But there is no video on YouTube about any specific implementation that worked. How gaps, sector tags and start were encoded?
I don't care what anyone says–I like your odd pronunciation of "Centurion."
Oh, god! This video looks like a best detective/drama movie. Thanks a lot!
Procomm plus😃😃😃
I used It many and many times in the past to up and download ASCII file from CNC machines in First 90s😍🤗🤗🤗
Computer Reset had ads in PC Magazine and Computer Shopper advertising IBM PC Convertible repairs. He repaired mine in 1992 🙂
You could try Spinrite by GRC on the drive but those heads sound baaaaad
The cut leg on the 74LS08 is an input into an AND gate. The datasheet for that IC shows an input transistor which is biased high through a pullup resistor. The inputs are connected to the base through diodes, so that if either input goes low, it will pull the base to ground and turn off the transistor. Based on this, if one of the inputs floats, the AND gate will act as a buffer. I'm not sure why they wouldn't just tie the two inputs together, unless there were issues with routing some other trace on the PCB which made this necessary.
Check out an Extron SRI 200. It is a little box that you hold up to a CRT and it will show the H or V scan rate. It has a detector inside. That way you can find things outside of a spectrum analyzer's frequency range.
Congrats on getting it running. I love that you showed a still of Adrian. That's exactly who I was thinking of.
Sounds like the hard drive cant get into second gear
8X305 !!! Yay! One of the weirdest processor chips ever made, although described by the manufacturers as a microcontroller. They were 8 bit processors capable of 5 MIPs, sometime used in disk controllers, and other devices where high speed (for the time) bit-wise and logical operations were required. It has a very limited instruction set, enough to make any seasoned programmer pull their hair out.
And I absolutely love the built-in test generator in the monitor. That's a nice find.
This guy looks like you, and sounds like you, and has the same name as you.
https://youtu.be/dfW0tMxNhmk?t=318
My dad was an execuive at GM, retired in 1993. In 1984 GM bought EDS just around the time I worked there as in intern one summer. Since I was in data processing, I technically interned for EDS, not GM.
I remember seeing a lot of EDS-badged PC's. I don't know if any of them were actually Centurion machines, probably not. Maybe EDS bought PC's and put their badge on them.
I'm pretty sure I've seen that RGB logo on stuff before. I seem to remember it from the old "red green blue" display cables – or the ports… or maybe entire monitors. It's a pretty dim memory though – so it wasn't something which was a "huge thing" – at least here in Denmark where I'm from.
Excellent! I love this sort of video, in depth troubleshooting and a great result!
The problem with the hard drive is it needs to be opened in a conditioned dust free environment, there's specialist data recovery companies that will do that and if necessary even transfer the platters to another housing, but they're not cheap and it's such an old drive they may not have parts if required. With your contacts you could ask around.
EDS out IBMing IBM 🤣🤣🤣
The Centurion logo plate on the keyboard was never permanently attached. It isn't flush, likely only having been laid there for the photos.
My comment went missing. The original keyboard looks like a Philips P2812 with Hi-Tek Series 725 switches. If you are looking for one.
74LS08 is a quad, 2 input AND gate the cut leg is the B input for the first gate.
Also great video, bit of history and a look over the machine plus a crazy backstory? What more could one ask for. Also while you might not hear the highpitched whine of the CRT you'r muc captures well enough for me to hear (or at least i think i do).
No one really ever "expects" Jazz Hands. Its a way of life, a way of being.
Post Cards dont work on XT's anyways. They dont have POST Codes.
Both of my ST-238Rs make that noise, but they work great.
I don't think they have a track zero sensor, so they head-bang their way home!