8" Floppy drive final repair and realignment procedure (ft. Usagi Electric)

Get your 3D printed parts from PCBWay: www.pcbway.com/rapid-prototyp...
Usagi Electric (Electric Bunny in Japanese) is visiting us. And I have the very floppy drive his Centurion minicomputer is missing. In this episode, we repair the head actuator brake with a professionally printed 3D part, and demonstrate how to realign the drive with a professional alignment diskette as well as without it. There will be professional bunnies at the end, promised.
See Usagi Electric install this very floppy drive in his Centurion:
• The Centurion Bites Back!
• Ferroresonant Transfor...
All you never wanted to know about 8" floppies:
• All you never wanted t...
Repair of the previous 8" floppy drives:
• 8 inch floppy drive #2...
• 8 inch floppy drive #3...
Stuff that supports the channel:
- Amazon links for the tools I use in the lab (supports the channel if you buy from there)
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- Support us on Patreon: / curiousmarc
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Get more technical info on the companion site: www.curiousmarc.com
Contact info: kzbin.infoa...

[@UsagiElectric]

I had an absolute blast, thanks so much for having me at the lab! Also, those little Usagis at the end were so adorable!

[@zyeborm]

Two of my fave channels together. So nice!

[@PCBWay]

It is AMAZING to see you in the video! 😊 Are you ready for your new project? We are super expected to see your next one！

[@RingingResonance]

Hey, it's the electric bunny!

[@minty_Joe]

Epic collaboration; CuriousMarc and Electric Bunny! Moar! Moar!

[@clonkex]

Finally I understand why your channel is called Usagi Electric!

[@sn1000k]

He's known for his enthusiasm and it checks out here :) Maybe my two favorite KZbin channels, and I'm just a humble artist, not even an engineer!

[@CuriousMarc]

You certainly can tell when something is finally working!

[@EricLikness]

@@CuriousMarc the relief and the JOY are palpable, even through the Interwebz.

[@kenromaine2387]

The Cats-Eye pattern will only show up correctly if to set the horizontal sweep to match the width of the scope screen. When set correctly on the scope you will see only one figure eight on its side between the two Index Pulse ( one rotation of the disk ). Then when you turn the motor to move the head In & Our to align the head one side of the Cats-Eye will get larger and the other side gets smaller. Then the Cats-Eye has both lobes of the figure eight the same height the head is center over the alignment track. You still need to adjust the Index to Burst using the Alignment Diskette to set the rotational position of the Index Detector so the time from the Index Pulse ( floppy hole ) to the ref. bit written on the Alignment diskette match spec. Head alignment is In & Out and the Index to Burst alignment is Rotational Ref. to the Index Detector IR LED. Hope this helps. The Index to Burst being miss aligned can cause R/W errors on diskette written on other drives. Just a tech tip of an old Centurion Centurion engineer, hope this helps.

[@CuriousMarc]

Thanks for the tips!

[@xtevesousa]

Could you elaborate on how the alignment track is created? As far as i can tell, with a single gap head, you would need two tracks, one to each side from the theoretical center of track 38, and both signals would have to be the same frequency but out of phase?

[@thebiggerbyte5991]

A big fan of both channels - and their respective bunnies!

[@EdwinSteiner]

Usagi in geek heaven, and he also got to meet Mike, Eric, and Ken. Legendary! I love the framing problems due to Usagi's height. If he visits more often, you clearly have to get a wider lens. Also, you are now the one KZbinr with an unlimited supply of "few minutes" memes. Well deserved!

[@CuriousMarc]

That’s it! Now I finally understand the KZbin short vertical format! It was made for filming Usagi Electric.

[@kenromaine2387]

Enjoy your channel. Thank you for helping with the Centurion minicomputer restore. Being a Warrex - Centurion employee for over 10 years I enjoy helping helping Usagi Electric's team.

[@IBM_Museum]

It is wonderful to see this collaboration!

[@stamasd8500]

Thank you for the donation of the floppy drive on behalf of the Usagi community. :)

[@eddiehimself]

Dunno if you saw it, but in his video Usagi was measuring the cutout for the floppy drive in centimetres. Absolutely based metric user in Texas. I love it.

[@dwagner6]

I’m really enjoying the confluence of all my favorite KZbinrs with your channel, Marc. LGR, Usagi Electric…can we get a Mr Carlsons Lab crossover???

[@elanman608]

This is pure nostalgia during my engineering apprenticeship during the eighties we had to write a primitive disk OS in FOURTH and use it to do a few line up items on 8 inch drives I forget which model but it was for an in house Z80 based automation computer. It seemed so cutting edge at the time. PS the idea of using a disk from a known good disk was used as an example of secondary reference Standards. Because everything in TV land was still basically analogue everything had to be aligned on a near daily basis using various meters, scopes and signal generators in the case of recording devices the BBC refused to pay for multiple copies of either the manufacturers or EBU line up tapes and produced their own secondary standards the master tapes being kept under lock and key in the maintenance supervisors office.

[@DK640OBrianYT]

How many are we of this odd breed ? Hundreds ? Thousands ? I'm also a dedicated viewer of both channels....and the other gentlemen, shango, phil, one-moment-please, et cetera. My first were eevblog and glasslinger.

[@alexpinkerton7459]

During a job interview back in 1988, I remember this guy walking out of an office with (what must have been) an 8" floppy. I had never seen one before, and for years after I assumed that I'd either dreamt the incident, or the stress of the interview, warped my perception of size. They are just too big to be real!

[@Ragnar8504]

I found a whole box of them when someone cleaned out a hoard years ago. Crazy things! And a crazy place, the guy must have repaired arcade machines and fruit machines judging by some of the stuff crammed into those two rooms. There was a bunch of 70s-looking cabinets but completely destroyed by damp.

[@richardhole8429]

Marc and David at the same time. What a treat!

[@arongooch]

What a combination!! Great work guys. Love both your channels

[@SonicBoone56]

Usagi is one of the most enthusiastic vintage electronics KZbinrs I know of tbh. It's contagious to the audience and makes us excited to see machines nobody has seen in decades. CuriousMarc has the insane technical knowledge and Usagi has the insane historical knowledge. I'd love to see you two collab again at some point, loads of old stuff needing some attention.

[@absurdengineering]

I’ve made my own alignment disks - 5.25 but the concept works on any stepper-driven drive. First align it. Then substitute original stepper driver with a micro stepping one. Set up for 1/4 step per pulse or whatever’s convenient. An Arduino then phase-locks to the sector 0 index and drives the writing of the thing. The drive belt must be in excellent condition for the phase lock to hold through the revolution - on an 8” drive with soft sectoring. You can also cheat with a hard sectored disk :) On 5.25 drives with direct-drive spindle it’s a bit easier. The feedback is right there.

[@eliotmansfield]

brings back memories of my first job aligning floppy disks at the age of 16 in the 80’s

[@davewright3088]

Oh wow, you guys take me back..! Back to the previous century, when I was a young pup trying to get an 8" drive interfaced to my Digital Group Z-80 machine. If only I had known then what I know now...

[@edgeeffect]

Back in the day, I always wanted a DOS program that would read the whole disk, for testing.... I never thought of just having a game that filled the disk and trying to load it! CKONG works great for this. :)

[@jeremiefaucher-goulet3365]

I loved the little wink at the end with the bunnies :XD LMAO What a great collab video this was Marc. Thanks for sharing with us.

[@dfirth224]

I have actually seen an 8" floppy disc about 25-30 years ago. The box of floppy discs was on a shelf in a storage room. I used 5 1/4" floppy discs about 30 years ago on my first computer. They REALLY did flop like a sheet of paper if you waved them in the air.

[@horusfalcon]

Usagi Electric led me here. You have a neat channel, Marc, and some neat bunnies, to boot. Love what both of your channels do.

[@TheGunnarRoxen]

Love it! I follow both you and Usagi (and am a patron of both) so I am especially psyched by this collaboration. Good job, Marc & David!

[@CuriousMarc]

Many many thanks for the support!

[@PCBWay]

Massive thanks for letting us be part of your wonderful campaign!♥

[@emdxemdx]

@9:55, the sound of the head seek brought me a ton of Proustian memories... 🙂

[@cbmsysmobile]

I used to fit a microswitch in these 8" drives with AC motors so it only spins when there is a disk in. Helps preserve the motor.

[@neilbarnes3557]

Takes me back to my days of lining up the heads on video tape machines... also, Bunnies!

[@melovescotch]

Like to see more bunnies in the videos!

[@bgbthabun627]

ikr?

[@benjaminhanke79]

08:08 "no cursing on camera" That's why I love this channel!

[@kermitinmountain6371]

UsagiElectric, Hewlett-Packard has been my favorite products, especially the family tv back in the 70's

[@douro20]

I remember in an old IBM PC manual where they talk about alignment of the Tandon TM100 floppy disk drives, where they showed what the waveform is supposed to look like.

[@abowman89]

I hope "Electric Bunny" sticks so bad, lol. Seriously love both channels.

[@jnelson4765]

Makes sense to collab on the 8" drive thing - y'all are both brilliant technician / restoration folks.

[@RetroJack]

I've been waiting for this episode - thank you so much! You're both woderful people and I love both channels!

[@rodgerwilco1]

Some of those 8 inch drives were my nemisis. The older IBM controllers used them for booting up, problem was the drive was always turning so the disk was continuously riding over the heads and wearing a track in the disk. You never knew that there was a problem until the box tried to boot up, usually after a power outage, in the middle of the night. Later models did away with the continuous turning.

[@EricLikness]

Nothing makes me happier than seeing Mr. Lovett's smiling face in the CuriousMarc lab in the Golden State❗Usagi Electric ftw.

[@FUNKLABOR_DL1LEP]

ok friday early afternoon - great weekendis coming up and starts with the one and only curious marc! ❤

[@zaprodk]

Get a Original Prusa MK3/MK4 and there is no "babysitting" - It's a set-and-forget printer. I use mine daily for functional parts. Never fails :)

[@CodeAsm]

love this unexpected collab (mini series). and what a cute flufs you got Marc :D

[@segfault-berlin]

You bunnies look like tribbles from star trek :D Sooooooo fluffy!

[@theafro]

It's nice to see that David got to visit with the King of vintage equipment restoration, I'll bet he was like a kid in a candy store!

[@maskddingo1779]

Two of my favorite youtubers and one of my favorite storage formats all in one episode!?! ...Also MPI drives!!

[@gordonbrandly4352]

It's quite a relief to see that I'll be able to check the alignment of my old 8-inch drives without needing that alignment diskette I haven't had access to for over 40 years now. Thank you! 😊

[@GodmanchesterGoblin]

Cool! I haven't seen a cats-eye pattern adjustment performed on a floppy disk drive since about 1978. If memory serves, the company I worked for was using Memorex hard-sectored drives. We've come a long way since then.

[@osgeld]

2 of my favorite channels at once (sorry Usagi, been watching Mark for far longer, but I have been following you since the start of the centurion)

[@donmoore7785]

Marvelous restoration, and demonstration of calibration.

[@danmenes3143]

Love these crossover episodes!

[@diego.alienigena]

nice to see you both in a video 👋

[@PowerPC602]

That's amazing! Love the work of both of you !

[@tylerellis4576]

Such a great collab!

[@Derpy1969]

I love these KZbin channel crossovers!

[@AmiPurple]

Your team of awesomeness only gets better with each video! Thank you

[@knietiefimdispo2458]

I have strange flashbacks to my 8 inch alignment phase. 1983 at Nixdorf in Paddaboan. ;- )

[@binarydinosaurs]

I loved that, thanks chaps. I've followed the Centurion rebuild right from the beginning and it's been a blast, 2 of my favourite channels working together :D

[@mlmmt]

Always good to see 3d printed stuff being used to fix old electronics!

[@TomKappeln]

The new Usagi standart, the C-Kong Standart ... Great work.

[@MatteoPascolini]

Thank you PCBWay for sponsoring this video!!

[@624Dudley]

Yessir, this channel rocks. 👍

[@crumplezone1]

Floppy drives are awesome, I still use mine on my Amiga and it so satisfying using this magical technology

[@fabiosemino2214]

Where I live I get to see in the wild 3 1/2 inch hares! Never been fond of floppies, both in Amiga and later pcs

[@SammeLagom]

I love those fat floppy drives!

[@dawnofclarity]

You had me at 5 1/4" bunnies.

[@user-vi3yl6wr5s]

Nature is a mutable cloud which is always and never the same.

[@dont-want-no-wrench]

great crossover!

[@FullMetalFab]

Someone needs to let Dave from Dave's garage know where to find a working 8". I recall him looking for one.

[@zh84]

Dysan (or dy∫an), there's a name that takes me back!

[@root42]

I have to repair a Micropolis based Commodore 8050 drive. Probably some of this will come in handy, too, even though the drives are 5.25".

[@analdisco]

Woow awesome combination!!!

[@bradnelson3595]

Very nice cross-breeding of channels here. Fun to watch.

[@aquaz_eu]

I was thinking about this crossover a lot.

[@melkiorwiseman5234]

I remember 8 inch disks. I used an older CP/M system known as a CommFile which used 1 or 2 of those and the user interface was through a dumb terminal. If I remember correctly, those were 128 bytes/sector, 26 sectors/track and 80 tracks/disk. I can't remember off-hand whether they were single-sided or double-sided though. So, either 266,240 bytes or 532,480 bytes of storage, depending on which they were. They were solid machines, both physically and electrically. There was once a momentary power outage right after I'd started a long program listing on the screen and the screen went blank, then came back on, and the listing continued from where it had left off. The capacitors inside the computer had kept it from resetting or even being bothered by the short outage.

[@trickyd499]

as a complete nerd I can confirm that this is super entertaining.

[@tsr207]

Used to use this type in the IBM 4701 branch controllers - the drives were a bit tricky to set up !

[@turbinegraphics16]

I remember from Champ Kong from a demo cd I got from a magazine.

[@Rob2]

Ahh... slow seek times! Way in the past I was using those IBM drives with a Maltezer Cross which stepped so slowly that even the slowest rate of the WD1791 floppy controller was too fast for them. Fortunately the operating system I used (NEWDOS/80 on the TRS-80) was able to do "double stepping" to read 40 track disks on 80 track drives. So I inserted a divide-by-two in the "step" signal and set the OS for double-stepping and the slowest rate, and it worked!

[@andymouse]

You've been ripped of by Harry Mudd, those are Tribbles !....cheers.

[@bigsarge2085]

Interesting.

[@charlieecho9621]

Une super rencontre

[@delimitnc]

Love your (and Usagis) videos as always! I know you might be doing it for KZbin purposes, but personally, I wouldn't mind some mid-repair cursing. It adds a nice linguistic human spice to the process! What epic repair has not involved its fair amount of colorful metaphors, after all?

[@CuriousMarc]

We never have mid repair cursing. I was just joking.

[@delimitnc]

@@CuriousMarc Not once, ever? Impressive.

[@loqAtMefi]

Electric Brake Bunny!

[@kencarlile1212]

Woo! Crossover!

[@ludmilascoles1195]

What do you get when you pour hot water down a rabbit hole? Hot cross bunnies!

[@delwoodbarker]

Love the phonetics on "swag," I have more of a twang, myself.

[@stevesweb]

So the drive came from Oklahoma City Operations, which proves there is more than Cowboys & Horses comes from Oklahoma! This comes from a real "Okie from Muskogee!"

[@williamsquires3070]

Well, you’ll need 3-1/2” bunnies next. 😊

[@jogginnoggins9918]

Neat!

[@jurjenbos228]

Don't throw it away! You need to be able to say "I have a broken brake in my brac-a-brac"

[@abdulmoeedraja]

5 1/4" and 8" bunnies 🥰😂😂

[@Powertampa]

I wish my software bugs could be repaired with a screw driver

[@your_utube]

The non-swearing minutes with a genuine home-made French accent was a fun one. It seems I must now invest in a bunny, but will the intelligence and experience also automatically rub off?

[@MrNoobed]

Wwhaaaat. How have you not included bunnies before

[@MVVblog]

2 of my favorite youtbers!!!!

[@garbleduser]

How far back in those particular bunnies ancestry would you find a tribble? I am guessing not very far.

[@berndeckenfels]

Bunnies!

[@68hoffman]

kool

[@WacKEDmaN]

should have played PAC-MAN on the PAC 65!

[@imark7777777]

well that was a weird crossover.

[@aserta]

Dunno that it will last, it's a repeat of the same thing that came before it. IMHO, i would've removed the OG motor shaft and swapped it with a longer one that reaches the other way around, through the bottom of the stepper and used an electric clutch. A Mitsumi (or Maruzawa) flat 12v micro electromagnetic clutch would've worked. I feel the mod is worth is, and swapping the shaft isn't a complicated affair (i've replaced at least 6 different brands from expensive to cheap so far, i've had no issues - basic tools sufficed, nothing complicated). Some of those clutches are about 1 cm thick, and about as big as the brake in apparent diameter. If that feels too dicey for some, then the pulley could've been swapped from the normal one to a modified one that incorporates the clutch and a small bracket. It's a specific clutch that has the slipring connector in the center. I don't remember what brand it was, but it's possible it was from Taiwan, not Japan. The clutch would be on when the motor would work, and when the "brake" would be applied it would disengage. The friction in the system would stop it very quickly. A piece of material touching the pulley would increase that stopping force considerably without forcing the motor to burn. At least i feel that's the case. I've seen them used in this fashion in old Xerox and other brands of printers. In particular comes to mind a design where they had a big rotating assembly, power transfer coming from a micro chain (the kind that's about half of a bicycle type) and to stop the inertia, they had a big piece of felt stuck on a square spring, inside a plastic "track" that made contact with the clutch/pulley assembly. I assume the component was meant to be swapped if it ever got worn down, but the one i found was neither particularly worn nor was the area full of fabric either (a concern, inside a part like a floppy drive). jm2c i'm of the opinion that you shouldn't repeat things that broke when it's obvious they'll follow the same path, but that's purely me. Awesome collab and episode. Whenever we repair these old machines, that's a future made better.

[@TheErador]

If the previous one lasted ~20 years and probably only broke because the plastic got brittle is it worth the effort to re-engineer the whole shebang? I would say not.

[@absurdengineering]

I like complicating things for fun sometimes, but that whole brake thing is not needed anyway if you want to do extra electronics work. Use a modern stepper driver. In many drives it can be retrofitted without altering original electronics, just unplugging the motor, and picking step and dir from a test point. Seeking becomes whisper quiet, the seek motor stays cool without turning off, everyone’s happy - no need for a mechanical brake.

[@Ice_Karma]

He looks different on your channel, somehow? It's interesting how a different camera and production chain affects things.

[@CuriousMarc]

It’s because I’m such a kludge at filming. I don’t optimize lighting or takes, don’t take B-roll, don’t polish it in post, have a rickety tripod, nobody’s miked properly, my camera is 15 years old. You just see it as it happened in the lab. I could sure hire a more talented videographer ;-).

[@Ice_Karma]

@@CuriousMarc You could, but I think your videos are just fine as they are! 😻