A great tip someone gave me years ago, for identifying the source of sounds in a mechanical system: You take a big old screwdriver and use it like a solid stethoscope, except you pin the little fleshy flap, the tragus, over the opening of your ear with the end of the screwdriver. So it's not 'in' your ear but pushing the tragus into your ear-hole. This transmits vibrations into your ear canal and bones without any air-carried noise. What you hear is any vibrations coming from wherever the pointy end of the screwdriver is touching. More weight on the contact gives clearer sound, but risks damaging surfaces obviously. This is really useful for diagnosing car engines, as it filters out so much extraneous noise, but in your case it would immediately tell you whether the noise is coming from the drum or the motor.

"That is how exciting it is to flip this big switch" And that, precisely, is what separates engineers from non-engineers.

I'm a Maintenance Engineer for a TV station in LA, California. On Sundays I'm the only one here in the maintenance room. I usually don't smile but to see you making progress on this computer brings me joy

"Quiet" in 1950's computer terms is basically "you can enter the computer room while the computer is running *with* ear protectors". A friend (now long passed away) once told me that the corporation he worked at in the early 1960's had a computer room where the printer did an emergency stop if you opened the door due to the noise levels...

- Cool computer you got there bro, how fast is the memory? - About 70mph

My Sunday afternoon routine: clicking "refresh" until the UE video drops.

Oklahoma University had two G-15s. A vent hood was fashioned just above each cabinet. When we powered up the computer we also turned on a hood fan motor to exhaust the hood to the outside. It reduced the cooling requirements considerably since most of the heat went straight outside.

I was at System Source yesterday for their repair workshop, and got the chance to talk with Bob. Great guy and great museum! Glad you’re working with them to get the Bendix running!

Just a heads up, you can buy a stethoscope with a long aluminum prod at the end if you will. I use it all the time in the automotive business and you can locate noises extremely easy with it and they're very inexpensive

You've inspired me; I saved a desktop from the trash with an aim to get it functioning again! My computer isn't as fancy as yours, though, but I'm taking baby steps! Another lovely episode! Thanks very much! I'm so happy to see it spinning up again!

4:15 - a washer went between the panels.

4:08 small washer falls into the machine... I hope that doesn't cause an issue later?

"a full tool song" is a good time measurement. I use it a lot

When I caught wind of this episode's subject, I knew I was going to be a fan of it. Glad you aired on the side of caution and replaced that insulation. Nice work!

I'm starting to watch you more and more! Just today I saved an Win 95 computer with all the essentials from going into to the trash! Greetings from Germany!

Our office furnace fan is out of whack, and the wobble gets me through the day...

Usagi Electric just got five more fans for his channel. :-)

'DC up and running code this year'. And somehow someone in 1958 said this and succeeded. Welcome to the future!

I have new old stock for the Bendix G15. For the tape reader/punch I have the delicate optical reader components as well as the lamp. And WHERE did you find a G15 emulator??!!

These old AC motors remind me of the motors in my 1950s model trains! I recently had to take one apart to replace the brushes and oil it.

Your enthusiasm is contagious. Keep up the great work!!

You should see about adding some sort of thermal switch to prevent the drum from spinning up when it is too cold. While you may be perfect about not spinning it up cold, obviously not everyone will be. You know that from experience as the first drum was likely damaged that way. Whatever system that does that should produce noise so that the person who flipped the switch will figure out what is preventing the system from turning on.

Watching David restore a tube computer made the year I was born has to be some of the best content ever. I love this and the centurion and of course the PDP stuff, I spent a lot of time programming pdp-11 machines

I am but a child next to this machine, thanks for taking us on your journey with it! Your excitement is infectious and I look forward to seeing more.

Amazing. I used a Bendix G-15 in 1967-1969 at the University of Colorado, Boulder, Co. The paper tape punch would get too hot so we always had to pull out the tape drawer when we punched a tape. Reader was ok. Even back then getting the vacuum tubes was a problem. The only place we could get them was a surplus store in Denver. I imagine they are impossible to find in 2024.

The high school I went to in 1970 had one of these (or a *very* similar model) in their Science Lab, which had been donated by an alumnus several years before when his company retired it. We got to play with it some, which I found fascinating. I still remember its most common error, necessitating one of us students to go get the Science teacher to come fix it. The terminal attached to it would just repeatedly type one line: w000zzy w000zzy (repeat forever until shut off with master switch). Glad to see this old beast, haven't seen one since then.

I really wish I lived closer to a computer museum like system source, would love to visit there one day. That reminds me a lot of how I handle bearings. I have oiled and repaired them that way many times.

All those selenium rectifiers on the tape reader! Good luck! Great video!

That's so exciting to see you're moving on, step by step, to revive this magnificent machine! Thank you for great episode!

Pulling a 40c fever. Watching your videos while sick. Absolutely love your content. I would love to live in your workshop lol. Have no idea how you use the computer but it's impressive to see :)

I had a grumbly ceiling fan in my bathroom - I did what you did, got some oil in it (I think I used chair lube that came with my office chair decades ago) - 1 year later the fan is still quiet.

“Sounds FANtastic” without a flinch 😂 🎉

I swear you dropped a washer in when removing the fan at 4:07, just in case you missed it.

Just yesterday, Tech Tangents has a video where he needed to remove some bearings (v=hudO51kU15w)... and at 8:14 he shows off a plumbing tool which is essentially a small bearing puller, available at either your blue or orange big box hardware store.

World's coolest 😎 space heater (for now). Cant wait to see it crunching numbers again.

07:50 - the long spin-down is a sign of the oil coating the balls and races thinly. The grease is still there, splashed aside and dry. With no fresh grease this is a very temporary fix. Ungreased bearings have the longest spin-down, however they do not last.

7:00 FANtastic

@TechTangents just used a faucet/compression fit puller to pull and press some bearings on a word processor.

What a project! Lots of work to make step-wise progress.

Well done! “Blue monolith” (chapter title) made me picture this in 2001 A Space Odyssey. Inscrutable alien object!

How to get oil into a bearing: heat the bearing in a 150 degree Fahrenheit oven, take out, drip oil on the race and then as the bearing cools, the oil will be pulled into the bearing. I’ve used this trick to get oil into Telechron clock motor rotors.

Fan-tastic work

In the UK we have The National Museum of Computing in Milton Keynes that even has a rebuild of the Colossus, it's a fair trip from me and I still want to go, but they have an awesome 3D virtual tour on their website.

Nothing quite like the hum of a vintage computer idling away, patiently waiting for some instructions from its master.

There's an anime related "This episode was mostly just fan service" joke in there somewhere. Great to hear the thing running up and ready for AC though, and good work brining those fans back around.

Beautiful meticulous work. Your fearless enthusiasm for such a daunting task is an inspiration. Big cheers!

Amazing engineering. Built to repair.

that purr of those fans make me so happy . congrats on getting fan spin,

Ball bearings in a fan? They really spared no expense!

Another step along the way! Thanks for the video.

The start reminds me of videos on repairing old Hornby and Bachmann trains.

Whooo!!!! This is so exciting! Seeing a commercial vacuum tube computer come alive is amazing for someone who grew up in the C64 era!

So many FANtastic moments in this video!

What a FANtastic episode! [sorry - couldn’t resist]

I love your excitement and enthusiasm, it's contagious

I rebuilt a lot of induction motors for one you should be using grease and not oil, oil will not last unless it is constantly applied unless you have a oiling system it should never be run in motors without sleave bearings also you can get the bearings off with no puller just cover the shaft with tape and heat the bearings with a hot air gun then remove the tape clean the glue apply grease not oil to the shaft in front of the bearing hold the part by the bearing you want to pull and tap the shaft on a hard surface it will pop right off heat the new bearing and regrease the shaft for assembly I learned that procedure from a 60-year-old guy who rebuilds Mill spindles I used it on my mill as well as many motors also for motors you want grease without high pressure additives it will last longer you may not be able to find bearings that have that but its always a plus and what you want if your repacking (as long as its a ball or roller bearing) also the drum has a preload nut there should be a torque spec for this preload nut you will probably have to build tool to hook up to the wrench but that can keep your bearing spinning on center if it wears if its to tight it will over heat your bearing

Great sound of the machine! I'm realy exited how it looks like.

Ah, those were the days of computing... when you needed specific training on just how to turn the thing on. "Have you tried turning it off and on again?" would certainly be a procedure with something like this! 😸

Congrats for well done dedicated work. Please keep going.

Injecting the oil into the bearing was a very nice trick. Sealing it up after made it perfect.

Very nice progress!

Amazing achievement. At 3mm/track on the drum , is it really .001”-sensitive on horizontal alignment? No one would dream of getting that finely aligned in a tape recorder dealing in analog.

Like most orange cats, he has Herb Alpert and the Tijuana Brass's "Spanish Flea" on repeat in his noggin.

Nicely done fan service! The bearing puller is safer than it looks and feels. Finding exactly the right bearings for half-a-century-old fan might be harder but not impossible. However, those kinds of ball bearings usually have great longevity unless you really overexert them. Cleaning the shaft and rotor from dust, gunk and rust is typically more important. Let them run for like ~5-15 minutes after oiling and they should be fine.

I like your enthusiasm and success in restoring these old computers

Oiling bearings will work for little while, but the oil will weep out sooner than later. From my experience these metal shielded bearings are better off just replaced.. the only way to get some new grease in them is to literally boil them in grease bath :) The rubber shielded ones can be quite easily be relubricated with grease. But those small bearings are like 2dollars a piece so youre better off just replacing them, use the bit more expensive ones like those made in south korea, they have better grease in them from factory and will last atleast 10times longer than the cheaper ones

Really wanna see it blinking and ticking and producing some kind of information! You're doing incredible stuff! 😎

small request if it's not to much. For the stars of the show the cute animals you always show, could you drop in the animal names if they have one. like the cat at the end of this video. Maybe do it like classic TV pop up Guest Staring Fluffy. I've long wondered what their names are and I'm sure you said them in videos over the years but my memory is like that first drum storage these days unreliable and needs to be serviced

Your restoration work is amazing.

It's nice to see 65+ year old hardware spinning up like new!

Nice job. Funny, I did the exact same thing with my tumble dryer bearings about 2 weeks ago that were sounding a little rough. Used some 3in1 oil on mine 🙂Those electric fan motors look fairly similar in size too.

Love this old beast, absolutely glorious space heater.

Amazing work!

Fan-Tastik Work!

I have to admit I jumped on my chair when you announced you were going to punch a hole on the bearings! But I guess it was the only option. And most importantly it worked! It purrs like a kitten now, well done!

This thing would be great for Canadian winters, I wonder if it would count as a primary heat source? Do math and heat the house lol

Those bearings have side caps. Those caps can often be removed to access the balls and cage. It makes it easier to clean with non water-based solvent like acetone and re-lube.

Ah, OnlyFans! Gone are the days when you could strip a motor just like that. That's the squirrel cage induction motor once common in record players. Fan-tastic indeed. I'm happy to see you replace the cable on the main one - going the extra mile, none of that sloppy half-assed workaround rubbish. Piercing the bearing cover was pretty clever, hope the edges won't get into the balls' way. Right in the Ass of the You-Ass-Ay! Nice to see your filming setup, and with some heavy editing, the results are spectacular. It's a very mobile setup, and I know you take shots in different locations and positions... unlike me, haha. Loved the Yoda quote! And again, as Guns'N'Roses sang, all it takes is just a little patience. Pet the kitty for me :)

It’s WHISPER QUIET!!

the rattling, sounds like there's a fan inside the drum's motor. perhaps it's slightly loose and contacting the motor casing.

One little tip is to make a jig to hold you fans if they fall over or seize then your motor will not flop about.

Saludos, como me encantan sus videos, máquinas asombrosas que nunca volverán, con una calidad de piezas y construcción meticulosa, genial ingeniera, hechas para durar cientos de años, era una ingeniería superior a lo de hoy día, dónde, la obsolescencia programada no tenía cabida, ni el recorte de investigación, ni la avaricia desproporcionada de los negocios hoy día, sigue adelante, con tu entusiasmo, tu pasión por la ingeniería de calidad, por encima de modas y avaricia financiera, tus comentarios y apreciaciones son muy valorados, abrazos desde Bogotá Colombia

Ok. Usagi! You just leveled up big-time. You are the best electronics KZfaqr by far now I find out your a Tool fan! Today is a good day. Lol. Thanks for your work! It is much appreciated!

16:27 can relate. Subscribed.

Galaxian on the Alto is so damn cool.

All this with an 8 year old GoPro and an Eos M. Well done.

I wonder if any of the people / engineers involved with the Bendix is still with us … would be so awesome

The nut and bolt power connection for your fan test is a solution after my own heart.

Great idea with the pick. I was wondering how you were going to oil those bearings in place. 3:30 I really like using heatshrink tubing on my screwdrivers. More durable than tape. If you spray some cheap hairspray on the screwdriver shaft before you slide on the tubing, it'll cause the tubing to stick and not slide off. It's an old AV installer trick. Excess hairspray cleans off easily. One can of Aquanet lasts a lifetime.

kirby bearing puller is about 20$ its for the 608 sized bearings though, but im glad to see it uses replicable bearings and not the cheaper brass/bronze sleeve type

23:00 - you lost a spacer there. Hope it doesn't cause any problems later.

I had to admit that you did a good job on the wiring repairs on fan. There are some concerns about applying the oil into bearing which is not a good idea, because it invite dust to build it up and become caked with bearing overtime. On the other hand, the grease are better it keeps dust out of it. I really respected for all of your work to bring it back to life! Thank you.

Well done, unless there is rust or damage inside the bearings they should run essentially forever with this method you used, if it is just the lube that is dry they should run more and more quiet as the hours goes with the fresh oil in them, great to see you replaced the rotten cables to the fan motor too, it was the right decision

Those fan motors are known as shaded-pole motors. Those definitely seem to be an older style, as modern ones are asymmetrical.

Bless you!!! And I hope you will fix the computer done as soon as possible!❤

Getting closer!! 😄

I’m guessing that the 5th fan and the big vent panel on the cabinet is to guide air through a filter to prevent dust being drawn in to the machine and especially the drum. Hopefully you can find a HEPA type filter to replace the filter element?

Your enthusiasm is infectious. Love your stuff. Cannot wait for that thing to run code. Then we will see if it can run doom 😜

This 1950 vacuum tube features top-mounted fans, much like a modern computer with a water cooler and radiator on top of a tower PC.

there's a video of one of these working on youtube, it's used to select projector slides when a kid selects an answer from a prompt, as an example of how computers could be used for education.