The Computer that Birthed BASIC and led to Microsoft!

The Altair 8800 - Bill Gates - Microsoft BASIC - ...and the story that ties them together!
For my book "Secrets of the Autistic Millionaire": amzn.to/3diQILq
Thanks to jonpaulmoen for preserving the source material for the Bill Gates sections!
For clarity, I'm talking specifically about MS-BASIC, not BASIC as a language. I don't want to rile up the Data General Nova users... they had BASIC beforehand.
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[@adriansdigitalbasement]

Good work Dave!! Looking forward to some future videos of you using the thing.

[@DavesGarage]

Did anyone else notice that the Altair shown in the Gates footage is a replica???

[@ernstoud]

How do we know?

[@javabeanz8549]

I wouldn't know the difference, but I might recognize it if it was the IMSAI ;0)

[@crypticquintessence4814]

I didnt notice, but i was looking at this recently and found an emulator/simulator of the altair 8800. You can see some how to videos on how to use it in youtube as well. Pretty fun

[@vcv6560]

They probably couldn't afford an original 😁

[@thatguy7085]

Not me… my first computer filled a large room. My father was a computer scientist at Georgia Tech. He would take me and my brother into his office when he worked late. I use to play the lunar lander program as a game… long before there was such a thing as a computer game, even before pong.

[@rayoflight62]

I designed similar circuits back in the day. The distributed power supply is vastly superior to the modern single-stabiliser designs. The reason why the designer of the Altair used a separate power transformer (and rectifier, filter and stabiliser) for the front panel, is obviously to maximise the dis-coupling from the power bus. This is because the logic board was overly sensitive to power glitch. They used tiny +V PCB tracks, while the power plane impedance balancing on the PCB wasn't practiced at the time. They had glitch problems with the interface logic, and solved the problem like we did with vacuum tubes. You can add a LM7808 to the feed entering the main +8 V bus, and remove the additional transformer. Add a VK200 inductor in series with the output of the 7808. Thank you for the video, it is very interesting to watch. Regards from the UK, Anthony

[@vcv6560]

What a generous perspective for those that hadn't lived through the time. This article came out I was in middle school. My EE uncle bought a kit, but didn't get it working. It was later given to me, but thrown out while I was away at college (someone cleaning the garage! - I haven't tried replacing it. I have to say I saw the title and hoped you would be talking about the PDP-10, it was here the Gates and Allen learned programming (a terminal at Lakeside) and their experience with that instruction set put them in the position once at Harvard to start working up their 8080 re-assembler and the Basic interpreter, without having to first learn TOPS10 and the DEC environment. Allen talked at some length about their development cycle in his book "Idea Man" (2011). I think this doesn't get enough notice, the advantage of years programming and especially low level assembly from their teens positioned them to get straight into creating their Micro-soft product and be 'first to market'.

[@southernflatland]

If you wanna get an idea of how much water electronics can handle (while powered off of course), well I entered into the electronics repair field right after hurricane Katrina. My late father had picked up an entire truckload of completely flooded computers and brought them to me asking if I could fix them. My heart sunk and I gave him the crazy eye like WTF you expect me to do with all this sh!t? But then after about an hour of brainstorming on it, I was like what the hell, why not try something at least? I mean hell, it was all a loss already, not like I could really hurt anything ya know. So I went to my nerd friend's house who happened to have a pressure washer, and asked if I could borrow it for a bit. Of course he looked at me like I was stupid, to which I agreed with him LOL! And then I went out to his back yard and proceeded to do the insane... After I pressure washed the few boards, I set them all out in the sun to dry for the rest of the day. By that evening I knew it wasn't gonna dry anymore than it was since the dew was starting to set, so I picked what seemed to be the highest spec board and brought it in his place to test. Sure enough the damn thing booted to BIOS! I ran out back where my buddy was burning hurricane debris in a bonfire, ecstatic to tell him the good news! He came right away to see this former hunk of mud booted up, and it was still displaying the BIOS screen, but it had locked up.. ☹️ Well, we figured it probably just needed a bit more drying time, so we shut it down and gave it another full day of drying time, and after that it ended up working perfectly! That ended up being a huge upgrade for me too! I salvaged quite a bit of that haul too, and as I continued this crazy pressure washing venture, I added a step to the process by using an air compressor to rapidly accelerate the drying time. Boy that sure helped a lot ya know... A little thing I unfortunately discovered during all this though, is that any which way I went about it, its not a good idea to pressure wash power supplies LOL! They pretty much all let out the smoke ya know, but the boards were pretty much all perfectly happy with this. Anyways, thank you for coming to my Ted Talk.

[@andygozzo72]

the psus would likely have survived and been ok but you wouldve had to be absolutely sure they were completely dried inside,

[@southernflatland]

@@andygozzo72 Indeed, you're likely right, but at the same time I believe some of the remaining water had infiltrated and saturated between the coil windings in the transformer and inductors. And given that they had been flooded in brackish muddy water, I think it had already compromised the insulation of the windings prior to ever trying to clean them. So unfortunately I don't think it would have really mattered much how long I let them dry, I think they were already compromised no matter what I did.

[@absalomdraconis]

​@@southernflatland : Likely true, though I have to say that using a pressure washer seems a bit extreme. I would have probably just used an ordinary hose.

[@eljuano28]

Last step after "washing" power supplies; isopropyl alcohol bath. Full submerge. Displaces the water trapped in the nooks and crannies.

[@southernflatland]

@@eljuano28 Sounds like an awesome plan, should I ever have a reason to try it again anyways. I'm sure I wouldn't have been able to come up with that much alcohol right after the storm though, we were half without electricity and struggling for food, clean water and fuel for vehicles and equipment after the storm. With supply chain difficulties and all, there's only so long before you can manage to salvage these sorts of things before they corrode too much to be saved. In my experience doing this, I managed to save about 80% of the boards I washed within two weeks after being flooded. I even salvaged a few hard drives, but I had to recover the data quickly to known good drives as there's no chance in a flooded hard drive to maintain a seal in the long run after being flooded. Edit: After about two weeks, the boards had generally corroded too much where pressure washing alone wouldn't work. I also ended up upgrading the first experimental board there with another flood salvage board, after I replaced 14 capacitors as well...

[@ScottPlude]

This video was heartwarming: It proves that even a (very well off) retired Microsoft veteran ends up using a bench grinder and garden hose if he follows his passion for old gear. I love it!

[@DavesGarage]

Thanks! I polished about 500 bolts on that damned wheel when I restored my truck! I prefer built over bought :-). And yes, eye protection!

[@drummerdoingstuff5020]

Eye hear ya

[@mercster]

Very well off...?

[@bubzuru]

@@mercster yes, he has alot of money so could of paid to fix those problems

[@StoneBrooks]

Adrian's Digital Basement is a great place to start on hardware. I would bet you had a loose connection from shipping. Nice work. c:

[@jamesfirnhaber984]

This is a trip back memory lane. As an EE major ('78 grad) for my senior project I built an optical bar code reader using the Altair 8800 as the processing engine. Yes, I had to use the toggle switches to load the boot loading program that interacted with the paper tape reader. I wrote the processing algorithm in assembly which I transferred to paper tape to load into the Altair. I had to teach myself assembly language programming for the 8080 which was fun to learn. I never used the basic interpreter as it had just become available and likely wasn't fast enough to do what I needed it to do. The reader was a laser that sent a reflected signal to an optical sensor that then counted on-off (reflected/not reflected) light pulses during the scan. This data was sent to the Altair which stored the counts in memory during the scan, and detected the stop bar to trigger code processing. The software then used these counts to perform the bar decode.

[@ConwayBob]

I was a Popular Electronics subscriber when that January 1975 issue arrived in my mailbox with that intriguing cover story. At the time my interest was focused on audio circuits, things like amplifiers, mixers, etc. -- and this issue prompted me to get interested in the possibility of owning and using my own computer. WOW! A Personal Computer! Years would pass before I finally had a computer on my desk, but that was the beginning of my software development career.

[@Darryl_Frost]

I guess you were really interested in how to read FM Turner specs then, I got into the computer field in the same way, here in Australia we had "Electronics Australia" I built the Signetics 2650 Kit what was June 1978 EA project.

[@andrewwasson6153]

Pretty much the same story and eventual career path. I saw the Mark-8, Altair and IMSAI computers in the magazines of the time and dreamt of the possibilities. Eventually, I bought a Netronics ELF II kit from a school friend who lost interest in it and I got my first experience programming computers using the CDP1802 instruction set. I still tinker with my CDP1802 based computer systems and I often resort to lessons learned programming the 1802 when coming up with solutions for writing software for current projects.

[@TurntableTV]

This man is slowly but surely building his own computer museum. Golden content, Dave!

[@Altair-Fan]

Built my Altair 8800 from MITS as a Kit of the month plan. Each month you got a part. Last part was the Intel 8080 processor. It worked the first time. Toggled in kill the bit as my first program. Got a serial board and hooked it to my "TV Typewriter" terminal that I built the year before. Later got cassette tape interface working. Sold it a few years later and built a Altair 8800B. Those were fun days!

[@DerrangedGadgeteer]

Working on c.1990 CNC machines, we'd start getting memory and bus errors randomly. A common troubleshooting procedure included removing the memory boards, taking them to a mop station, hosing them down with hot water and floor degreaser. We'd rinse them off, blow them dry-ish with compressed air, then let them air out until the next day. It was startlingly effective, and I don't know of killing a single board that way.

[@AndersNielsenAA]

Well, the only real danger is leaving behind conductive liquid(tap water) that might short pins when dried(less of a problem with large dips) - or the always present danger when handling old boards: static. My favorite mixture is still demineralized water+isopropyl alcohol in an ultrasonic cleaner with a drop of fabric softener for the anti static properties - saved quite a lot of toilet iPhone logic boards that way. And the fabric softener also makes them smell less like toilet.

[@bobriemersma]

I was a college freshman when that magazine came out. Despite the excitement, I was scraping by just paying for school and the Altair 8800 was hilariously expensive for what you got and unattainable for me at the time in any event. If it wasn't for competition by the 6502 shortly afterward I hate to think how long PCs would have remained expensive luxury items. I don't think Intel or Motorola ever intended to address personal computing.

[@dycedargselderbrother5353]

Minicomputers occupied a role smaller than mainframes and microcomputers would be the next step down in this continuum. But the target audience was still medium to large businesses who could afford to pay 4+ figures for a microcomputer rather than 5+ for a mini or 6+ for a mainframe. The people who formed MOS and Zilog figured this out and left Motorola and Intel, respectively, to create the personal computer revolution themselves.

[@timjackson3954]

It was summer time at university in the early '70s and I was sitting in the sun on the lawn doing some reading when a fellow postgrad came rushing over with a magazine advert. "Look you can actually buy a computer for less than the price of a family house! Personal computers have arrived." The machine advertised was a DEC PDP8 with 4096 12-bit words of memory.

[@datadude67]

Motorola rejected employee Chuck Peddle's proposal to create a low cost stripped down 8 bit microprocessor. Chuck recruited some colleagues and together they created M.O.S. (M-O-S not MOSS) in Norristown, Pennsylvania. This came roughly at the time that the American calculator manufacturing industry began to wither on the vine. Market maturity and commoditization possibly aggravated by T.I.'s alleged attempt to compete with the Japanese suppliers by sucking the remaining profit out of the calculator industry by undercutting its supply chain buyers. Meanwhile, Auschwitz survivor Jack Tramiel, had transformed a small typewriter repair shop in New York into a successful calculator and office equipment manufacturer in Toronto called Commodore Business Machines. Commodore's biggest supplier of calculator IC's was Texas Instruments. Jack was outraged that his primary supplier, TI, in an arguably shortsighted and self serving move, would undercut the profit of their long trusted supply chain partners by selling the chips to their own calculator division at a large discount. This was a market that Commodore had worked hard to shape and grow over the years. Dismissing Commodore's interests was a major gaff that would later hurt Texas Instruments in a profoundly negative financial way. Tramiel's outrage at the alleged unethical squeezing of Commodore's supply chain would take years to forget, if ever. Jack's aversion to the feeling of being taken advantage of, coupled with an instinct for survival led to the purchase of MOS Technology, a cash starved semi conductor design and fabrication company. MOS would give Commodore the ability to create their next big thing in house: The Commodore PET. A computer that would be simple and affordable. A personal computer for the masses, not than the classes. I digress.

[@daveturner5305]

Oh boy, this takes me back to '75 when I ordered a Z80 single microprocessor, delivered in '76. That was £120. 16 1kx8 static ram (another £180) and sundry components. Home brew at its best. 7 years later it was 64k dynamic, cassette interface, improved graphics monitor (B&W only) all on two 12" square self-etched pcbs with point-to-point wiring.

[@longjohn526]

I was on one of the KZbin channels that does computers and people were complaining about the high cost of parts like CPUs and I mentioned that when the 386 came out it went for $399.99 and those were 1985 dollars and building a decent IBM clone would set you back $2 grand .... In the 1980's you had to decide whether you wanted a decent car and no computer or get a computer and drive a hunk of junk.

[@brostenen]

I went through the late half of 1980's and to now. So much have happened, and in 2012, I began getting into vintage computing to relive what I experienced. Some call it retro, but I like vintage better as a term. And it has taken me to the level of building replica's of 8-bit machines. I have more or less what I need of original hardware, but building replica's that are close to original as possible, with the solder iron. Is something completely different and way more awesomme than just buying a used machine, recapping and then playing games. More fun to actually build. Games are fun to use as burnin software. But I get bored of gaming after 10 to 30 minutes. 35 to 40 years ago, it was different though.

[@cpuuk]

As with the Commodore, oxidization is the number one thing to check for on this old kit, so a good clean of the connections is a great place to start.

[@georgemallard4120]

Those big electrolytic capacitors will give you trouble later. That is the first thing to go. Best practice is to replace them as they sometimes make a nasty mess when they fail.

[@absalomdraconis]

Good to do, but not necessarily a priority, as some years were much worse than others: the years we usually hear about were using "capacitor plague" capacitors, which were accidentally produced during _multiple_ periods of time. In contrast, some other periods of electrolytics merely slowly die instead of oozing out.

[@pcrepair7456]

Check uF and change those caps as needed. I agree. Also Dave probably fixed the loose wire with his overhaul, as it was more a overall approach not component based analysis.

[@dstrome]

Would love to see you recreate the first time Alan got Basic running on the Altair when he flew out to New Mexico. From entering in the boot loader to reading in the tape to actually performing validation checks to show it actually worked.

[@robertleemeyer]

Beautiful, just beautiful. Always wanted one of those. Read the original article when it came out and knew immediately my future profession was going to revolve around computers. Now my home office is jam-packed with computers, both ancient and (nearly) new! Glad to see you enjoying it so much. Keep up the good work!!

[@MillBrookRailroad]

I'm impressed that you lined all the screw slots in the same orientation. I used to work in assembly at Allen-Bradley/Rockwell Automation (building CNC control computers) and we didn't care how the screw slots were oriented as long as the screws were present and properly tightened. That was our level of precision for screws. As you could imagine, it was far more important to get working machines out the door and into customers hands. Good on you for taking the time to get the old Altair back on its feet.

[@LordLarryWho]

Hi Dave. Take it from a guy who has been working on a Raspberry PI based brain for a DIY smart still for a couple years. Distilled water isn't conductive. No electrolytes, no conductivity. I learned this when I first approached the idea of detecting the level of alcohol in the distillate. I already knew that ethanol wasn't conductive and figured water in the distillate would indicate that there was no more ethanol to extract. Nope, distilled water has no electrolytes, not conductive at all. So, distilled water is perfectly safe for washing down circuit boards with.

[@katbryce]

Is the water still non-conductive when it dissolves metal salts and oxides from the corroded parts?

[@vcv6560]

@@katbryce ohh, memories of Chemistry lab 40 years ago. Psyche!

[@LordLarryWho]

@@katbryce Equally as conductive as any other liquid that you would use for the same purpose.

[@coisasnatv]

Former Sony Engineer here. Electrolytic capacitors (e-caps) has a lifespan of about 6~12 years (you can read that in more details in any e-cap datasheet), after that, it start to degrade. Since your computer is from the 70's, your computer need a full electrolytic capacitor replacement (recap) before start to operate full time. E-caps are made of an electrolyte and *water,* since you water your board (not recommended) that might did something to make it work but it will eventually fail again if you don't address this issue right away. We don't clean PCB with water because when the water or when the PCB are in a high humidity environment, the moisture expand. When it get into the layers of the fiber board or under the copper of the tracks and expand, it creates bubbles. Good luck.

[@richardthunderbay8364]

I particularly liked your presentation of the history of the Altair and BASIC. Fascinating stuff.

[@fuzzy1dk]

8:27 that is basically how it works today, there isn't anything on a graphics card, or motherboard for that matter, that runs on 12V other than the regulators that make the much lower voltages for ICs and IOs. Distributing something like 1.2V at hundreds of amps would be very inefficent and basically impossible

[@alexandermaasland3494]

What a treat to watch this video, I love seeing this old 'stuff' getting reanimated as well as getting some well deserved love and attention from its new owner :) Thanks for the video Dave, keep it up!

[@petervanderwaart1138]

Back about 1973, my employer bought a Data General minicomputer. Usually, booting up one of these required entering a bootstrap of about 23 words using switches as you described, but we had the latest version with an extra chipmwith the bootstrap encoded.

[@brianstarr]

I bet shipping jostled the wire lose. Nice job. You'll be mining bitcoin in no time.

[@mep1624]

…The video was an 8.9, then I saw the alignment of the screws in the back. Instant 9.4! Either way a thumbs up from me. Thank You again Dave.

[@G7LWT]

For me, this has been the most interesting video so far (and I really enjoyed many of the others) - thanks very much for making and sharing!

[@melkiorwiseman5234]

It's my understanding that the "computer that birthed BASIC" was a mainframe system on a college campus. It was noticed that the computer was standing idle most of the time and it was capable of handling input from multiple users at the same time. So BASIC was developed as an easy way to program the computer (a lot easier than the other languages which existed at the time, which were oriented towards particular fields, such as COBOL for business and FORTRAN for mathematics). BASIC was instead designed to be versatile and easy to understand. Computer terminals were located in accessible places around the university, all linked to the computer so that anyone could program the computer in BASIC and save their programs on the computer. It proved to be a huge success and this was the real birth of BASIC. Although the Altair may have come first in the home computer market, it's my opinion that the TRS-80 was the first really popular "home" computer to use BASIC and led to the huge popularity of incorporating a version of BASIC into all home computers during this era.

[@melkiorwiseman5234]

Oh, and congratulations on fixing the power supply. I know how much fun it is to work hard on something not knowing what the result will be and then find that your efforts were actually worth it.

[@patrickmcginnis7]

I so agree! Microsoft didn't birth BASIC. I mean MSDOS was good. Basic wasn't a thing on my univ. mainframe ... it was Pascal or Fortran 77, but that was in '88. The dummy terminals sucked at text editing. I still have my TSR-80s in boxes.

[@alpaykasal2902]

I love seeing cameo appearances of Amiga's and earlier Commodore, back to the PET. Thanks, and great work on your clean up and repair.

[@stephenalexander321]

This is absolutely great! I've had all sorts of old products that I wished I could repair or augment. This is inspiring. Very nice work! Thanks, Dave!

[@fattomandeibu]

Using your resources to show off such great piece kit that the vast majority will never get their hands on is such a great thing to do. Absolutely fantastic stuff. I cut my teeth in MS BASIC, but the only thing I remember these days is shift and run/stop, then typically after about 5-10 on the tape counter, press the Commodore key when the file name appears.

[@dsuess]

Dave, this was pretty neat to hear the history and your detailed cleanup - especially the cleanup. Thank you as always for your videos! I have a few "portable" PCs from the mid 80s which my dad first introduced me to, BasicA programming. As you can imagine, as a 5yr old I was more excited to make it print funny words. But it sparked my journey to become an engineer.

[@Learnerofthings]

I miss hardware! I first got into computers in 1996 when the 486 was being phased out for the Pentium, but I got to work on a lot of older systems using MFM and RLL drives and how to manually setup HDs using CHS. Good old days of computing.

[@javabeanz8549]

what was that command again? Open debug and enter g800?

[@thejoneseys]

@@javabeanz8549 g=c800:5

[@javabeanz8549]

@@thejoneseys that sounds like the standard one, there was another one for some controller cards, but it's only been about 30 years since I moved over to IDE (PATA in newer terms)

[@ahayesm]

Washing a dirty computer is a perfectly valid first step for troubleshooting. I got a fully dead laptop that was coffee spilled to perfect working order just by washing the motherboard (and chassis) under the sink, rinsing it with IPA, and blasting it dry with an air compressor.

[@MarkSeve]

Darn, seems I'm already subscribed. Thank you for sharing your adventure into antique small iron Dave.

[@petersterrantino6602]

Hey Dave, Lucky you! The Altair has escaped my capture since reading that article as a kid back in ‘75. Glad you found one… I’ll keep looking! Thanks for the great content. Would love to see you get this up and running MS Basic.

[@Theineluctable_SOME_CANT]

Great video, Dave. Your channel is as fantastic as you are. Kudos, brother!

[@AiOinc1]

I would LOVE to see more of your computer museum back there, I bet there's some real forgotten gems laying around. Will you ever acquire a rack mount PDP machine or even a Teletype 33? Just to complete the childhood memories, of course. Given enough time to dry, any component should in theory survive water, especially distilled, which is nonconductive. However, using compressed air is usually a no-no! Many compressors can fling water or oil under components or in the case of transformers and several other fragile components can often break them irreparably. Transformer connection was absolutely the most likely point of failure, I can't imagine an add-on transistor having caused the issue unless it was dead short to ground or something.

[@DavesGarage]

Wow, I'm so tempted... there's a mint PDP/11-70 front panel on eBay right now, but it's $4200. I might hate myself later, but that's steep!

[@zeruty]

@@DavesGarage Dave, have you thought of seeing if you can film at REPC's little computer museum at their Seattle location? Or searching through their back room like MetalJesusRocks did at their Tukwila location with all the commodores etc that the public don't normally get to go through to purchase?

[@absalomdraconis]

​@@DavesGarage : At that sort of cost, you'll probably be happier buying a boat load of switches and making a panel yourself.

[@JohnDoe4321]

@@DavesGarage If you really want "the computer that birthed [Microsoft] BASIC", and score some serious Nerd Points, you need to get yourself a DEC-10! P.S. MS BASIC was definitely influenced by DEC's BASIC. Not an exact clone, but you can clearly feel the influence. Especially when you compare MS BASIC with the BASIC's on other mini/mainframe systems (e.g. compare to HP or IBM).

[@garystewart3110]

I'm 43 years old, I only got in to this back in the days of 386 and BBS days which at that time was right at the key to our internet. I was fortunate to be part of that transition. So cool to chat with MS guy from that time :P Thanks Dave for sharing your skill and taking the time to make some very fun and informative videos!

[@thecandyman9308]

Fellow Xennial. We were so fortunate to go from "functional" personal computing to the web by the dawn of the new millennium. We have roots in "analogue" but took flight in "digital".

[@dont.beknown5622]

Awesome video!! For someone that "doesn't know electronics" - you show great patience and attention to detail. That by itself will fix most issues... Thank you from an old tech...

[@stevejohnson1685]

I built a contemporaneous but non-S-100-bus computer (from Carl Suding's Digital Group) in 1974, which actually came with a ROM monitor that could load from cassette tape directly. It used a linear power supply and case that I scrounged from the discard pile at Argonne National Laboratory (where I had a summer internship). Sounded like a hovercraft when it was running. Ah - hand-assembled 8080 code! I can remember hexadecimal instruction codes to this day. Thanks, Dave!

[@steverae68]

OMG - love hearing about old retro kit, did a presentation on other birth of computers … based loosely around the storyline of Pirates of Silicon Valley. Covering Microsoft and Apples early days. Loved researching this… What an amazing video ❤

[@MarianoLu]

Great work Dave! Been following since the early days and love this old tech videos. Looking forward to see you running MS Basic in that awesome Altair! By the way I also follow your other channel since my daughter also lives in the Spectrum it has been very close to my heart

[@skyrocketautomotive]

I've always wondered just how the generational leap was made from the Altair, and in a few minutes you've already explained it perfectly! Fairly new to the channel but binging you vids like noone's business Dave! Cheers!

[@glasser2819]

Uncle Dave, this linear power supply rely on the load from the different boards to bring down the voltage of transformer secondary winding. I started learning electronics in 1976... Flow goes like so: > On/Off Switch > Primary Fuse! > AC Transformer 120/07VAC > AC Rectifier diodes in bridge > DC Filtering Capacitors > Secondary fuses! > Dispatched to daughter boards for local regulation. The voltage regulator is where the most heat dissipation occurs. TO3 were used. Caps advice if you will: 2 light Blue caps seems to have been replaced. These parts are known to age and are very cost effective. Change the whole supply board cap collection for $1Ea. Keep the same caps voltage but bump up the uF to get smoother filtering. "Low ESR Caps" not necessary here but nice upgrade as well. Repete filtering upgrade after each local regulation circuits. You absolutely need clean DC Power to feed digital TTL gates, right? C-MOS chips were right around the corner... MIL Specs 👍

[@tekvax01]

Good Job Dave! Unregulated and Linear regulated supplies are really the best way to start understanding electronics. Once you get the basics, try to tackle a switch mode supply! They are *much* *more* fun!

[@MarkHopewell]

Any TV's from the late 70's through to when they became obsolete are a good way to cut your teeth on SMPSU.s! Wouldn't it be amazing if someone still had access to the old Thorn/EMI/Ferguson 'SYCLOPS'-based SMPSU/LOPS-based chassis to work on. I think the 7800.x chassis? The 'Ipsala' -based SMPSU from Nokia would be nice to aim for. Also maybe some of the Thompson/Ferguson VHS VCR's (3V30's+) from the late 80's - early 90's too. Heaps of directly-coupled silicone in those SMPSU's. Lovely!

[@arnotek]

I remember when that magazine came out. I was programming IBM mainframes in assembly language at the time and I knew it was a big deal. I still have that magazine issue locked away all these years later. Gates and company built an empire and I have a magazine put away - yeah, missed that opportunity.

[@HelloKittyFanMan]

Cool video, happy Christmas!

[@JeremyMcMahan]

Great video once again. I really enjoy seeing this tech that was just a bit before my time.

[@timjackson3954]

Washing down a computer brings back memories of my industrial electronics work. Yes, water wash is no problem (with any batteries removed), something I often did to contaminated PCBs. The key is thorough drying. Half an hour in an oven set very low, or overnight in the airing cupboard generally sorted it. Water only hurts electronics if it is under bias and electrolytic corrosion goes on. But flood water leaves muddy residues that can be hygroscopic and can conduct, so a clean wash-down is important. The most memorable occasion was the SMPS from a toffee wrapping machine. The filter-less fan had ingested sugar mist for years until the whole PCB was covered in a layer of toffee. A good soak in the bath and thorough drying and it was good as new.

[@hernancoronel]

At 12:57 “…screws all nicely aligned…” phew! Sooooo nice for OCD, thanks for the great video!

[@billbez7465]

Wow. Fantastic video. I am a computer history addict , so I really appreciate these videos on vintage PCs.

[@Jiburley]

This took me back to the early 80's when I got my hands on an already old 2650 processor and board to build. Fun times.

[@davidgekler]

I worked for a company in 1977 -78 that had exclusive to sell IMSAI 8080's - essentially the same as the Altair ad I think made by former Altair employees. One summer at Ultra Byte I sold over 150 of them , 20 to NASA - they claimed to be using for "mail system" but a couple years later I saw them in mission control consoles.

[@jacobpalm]

I am thoroughly enjoying your videos on the KIM-1 and Altair 8800. In recent years I have been playing around with assembly and direct hardware access on older PCs, and I feel that it gives such a great understanding of the internals of any modern PC that's hard to get otherwise. These videos go even closer to the metal, and you do a fantastic job of explaining things in an understandable and even entertaining fashion. Keep up the good work, Dave!

[@michaelangel7907]

Great! Congrats, and thank you for making the video.

[@canuck11]

My start was a little newer in the Apple II+ but it lead me down a 30 year path in computer tech.

[@matt_b...]

One thing's for certain, the smoke hasn't been let out. Yet. Thanks for the amazing and engaging content.

[@whitneyeaton5585]

well done, thanks for your contributions to the buisness. i recently aquired my AA in computer science and am looking forward to revisiting an Commadore 64 , sitting in my garage after a few decades! it is at least protected in a box, but it is old, i want to see how it will run , soon. thanks for your videos.

[@boyscout399]

I wasn't even born when most of the tech you show was made but I love seeing the origins of it all

[@Pretellier]

Lots of fun and nostalgia for those early home computer days . When I noticed this video , I groaned , thinking that some rich retired software engineer had bought this Altair for a Million Dollars or twice , but it was heartwarming . I hope there are more videos on this ! How about bringing in an Electronics Tech to check and explain the circuitry ? And another video on very early programming ? Thanks for showing this video , Dave !

[@Monotoba]

My father saved and purchased an 8800. I remember it came in large boxes. One every few weeks until we had the whole thing. I was only about 11 or 12 years old but after a bit my father had me soldering components to the pcbs. I wasn't allowed to power anything on until he checked the board assembly. While I don't recall a lot of what we did with the Altair, I do remember the joy and excitement when we got a Lissajous pattern on the oscilloscope. I do remember hand assembling short programs and entering them by hand. I know data added a couple cards to the Altair of his own hardware. His interest was more in electronics than programming and I wrote most of the code for the Altair. We didn't have a terminal so we build a keyboard on a piece of wood paneling with a few dozen little red Radio Shack push buttons. The letter each button represented was mark on the board above the switch. Later my mother wrote tiny little stick on labels for each button. White paper labels with blue ink that eventually smeared and wore off. Eventually, my father started a TV teletype writer to use as a terminal, and got his hands on a paper tape machine. I don't think he ever got the paper tape to work and I'm not sure he ever completed the tv typewriter. But that Altair gave me my love of coding and electronics even though I only used it a couple years before the Coco and Commodores became the thing, these too seemed short lived and were replaced by a Tandy 1000. My coding skills went from 8080 machine language, to BASIC, to Pascal, Forth, C, and C++. Today, I do things mostly in Python and C, and occasionally in Dart and JavaScript. Though of late I played a bit with Algol, FORTRAN, and Pascal just for kicks. There is still a lot one can learn from revisiting old hardware and old programming languages. If nothing else, I believe every developer should have to write an animated side scroller on one of these old systems as doing so requires a good understanding of the hardware, software, and the limitations of the system. This like many of your videos has brought back some fond memories. Thank you!

[@PyroX792]

What a cool piece of old kit! Great job getting it working again.

[@Thatdavemarsh]

That trs80 brought back memories! I remember using turtle to draw things back in 84 and the slowly learning basic in 86-88

[@AndersNielsenAA]

Nice one, Dave! I immediately took offense with the title because I knew the PDP-10 technically “birthed” Microsoft BASIC - and of course not BASIC itself either but just the implementation. But yeah, I know it’s not easy with the titles! But never mind the title - I really like the work! With old electronics a good re-assembly really is the equivalent of turning it off and on again. Good job with the restoration! (Coming in a video soon, I hope: “changing capacitors on an Altair 8800”)

[@mp-kq3vc]

I saw a documentary not long ago about Dartmouth Basic. One of it's creators mentioned that they did it "... in the year 1964 BG... Before Gates!" Hahaha loved that.

[@randy7894]

Good guy Adrian! The super entertaining troubleshooting channel (for beginners and amateurs) Loce that guy.

[@visitandolosclasicos]

Hello Dave !, (that sounded Hal-ish in my mind as I read it lol) I just discovered your channel and I like it a lot when you work on vintage computers! I'm a a retired it tech that it's rediscovering the joys of basic programming after decades of c coding. My main coding computer is my trusty c128 and lots of other emulated computers on my Windows pc lol, thank you for such great videos!!!

[@ByronWatts]

That issue of Popular Electronics is where I started programming. I was in High School when I discovered it in the school library. That and quite a few other issues were fascinating and made me want to be a programmer....which I am. Thank you for sharing!

[@seikibrian8641]

I started using BASIC -- specifically DEC's EduSystem BASIC -- in 1973. We had a half-dozen ASR-33 teletypes as interfaces into a DEC PDP-8, 3 of them connected remotely via telephone modems, and we saved our programs on punched paper tape. Each terminal was allocated 4k of RAM. My, how things have changed.

[@stephenalexander321]

In 1976, our teacher had a 4004 from SouthWest Texas Technical Products Corporation. It held 4kB of RAM. It was about the size of a car radio, with DIP switches on the front panel for input. The only other input was a standard shoebox casette tape recorder. It took over 20 minutes to load a little character-based StarTrek game! The manual was a good-sized book, but we had a blast with that thing. Programming was an electronics wonk's game back then. A few years later I was coding on an IBM 020 keypunch desk, and setting RPG programs on plugboards. The good old days!

[@markmuir7338]

Interesting video - I love these history lessons, with actual hardware! A quick point on your analogy with sending unregulated power to the cards being as if modern PCs sent a single voltage to the graphics card and the card converts it to what it needs: actually they do - GPUs and their memory run on very low voltages (~1V). They pull power from 12V (via the slot and cables) and contain lots of voltage regulators (VRMs) to do the conversion. VRMs and their passive support components make up about half the components on modern graphics cards!

[@Hama46]

My dad was an installer for Western Electric, working on the first generations of ESS. One day he came into my room, all excited, and threw that copy of Populatr Electronics on my bed and told me the computer age was starting. Within 5 years he bought an Apple II+, serial number in the 2000's. He had to lie to my mom about the cost, but both me and my brother used the hell out of that thing and have had careers in tech. So worth the cost, I think.

[@makermelissa]

For some reason I enjoyed this video much more than your usual videos (though your tales at MS were great too and why I subscribed). It’s probably because this video just had a great story. Thanks for sharing.

[@makermelissa]

Also I think you could improve the title or thumbnail as they didn’t really do this video justice. I thought you were just going to talk about the computer in general and not about what you had to go through to get it running.

[@DavesGarage]

Would love your suggestions for thumbnail and title if you've got any!

[@rigilchrist]

Hi Dave. I'm in the UK. My first microcomputer I built from a kit. It used Nat Semi’s SC/MP (SCAMP) microprocessor. It had a simple instruction set and like the later Altair, there was no assembler so we had to manually enter the opcodes to create a program. Around that time, S-50 bus PC’s appeared and then the S-100 bus, as in the Altair 8800. Bill Gates’ anecdote about demonstrating their DOS to IBM relates how he realised they didn’t have a boot loader - so in the demo, they had to write a boot loader and then switch in the opcodes for it, all in front of the client. I went on to work on a product that incorporated the LSI-11, DEC’s microcomputer version of the PDP-11. It ran the RT-11 DOS which was way ahead of CP/M (and IBM DOS). I bought a home Z80 board with MS BASIC in an EPROM and a friend disassembled this. We were all astonished to see that the interpreter used every single byte in the EPROM. Someone, presumably Gates, had hand-optimised the code in order to save space. For example, there was a three-byte jump instruction in part of the code, but another part of the code jumped to the second byte of this, which then performed a different task! Great channel, thanks!😊

[@laurenceglazier]

Excellent, thank you. Though the first computer I unscrewed was an IBM PC, it all looks very familiar and I remember coding 8080. Nostalgia!

[@lignow9762]

Another good vid. Thanks. For old electronics repair I recommend Mr. Carlsons Lab.

[@teamsafa]

Yea, I remember the Altair basic. Microsoft had a 4K, 8K and a 12K version of the basic. Back in the days i did a disassembly of the 12K basic so I could port it to CP/M. Had to undo a lot of smart tricks that was in the code to make it assemble and run under CP/M. One of the really neat codes in the 12K version was the routine to check for variable type. The 12K basic supported integer, string, float and double. The size of the variables were 2, 3, 4 and 8 bytes respective. It does a compare of size with 8 and then three decrements and after this the flags is set as follows: Minus set if integer, Zero set if string, Parity set if float, Carry cleared if double.

[@weshowe51]

You win the prize for coolness. I was a subscriber to PE when that issue came out. Financially, acquisition was out of my league back then. You may want to check and/or replace the electrolytic capacitors on that supply board. They are a pretty common problem on most old radios and other vintage electronic equipment, as they depend on a chemical process forming the insulating layer between the foil plates, and those chemicals degrade eventually. It looks like two may have already been replaced, the rest may be barely operational.

[@artmezins3785]

Before the Altair, I was already working on my first PC using the Radio Electronics July 1974 8008 based PC "PCB kit" while in college (I mailed my check with a hand-written note - way before the internet). I designed my own 2KB SRAM PCB. After quickly tiring of the lousy entry switches I had (all parks came from surplus stores: Poly Paks, Jameco, John Meshna, etc.), I designed and made a hex data entry PCB to enter data (with auto-step) for data or setting the starting address. For the PCB, I used a direct contact positive with a 1:1 tape-out which used a very poisonous tetrachloroethane solvent developer! Then etched with ferric chloride solution. That PC worked great, albeit slowly (125KHz clock). I used it with my senior design project to program Intel 1702A 256x8 UVEPROMs on another PCB I made. I got an A for it. Way too much work, but fun!

[@gali01992]

I was planning on getting an Altair 8800 since they first came out but when Radio Shack announced the TRS-80 model 1 with keyboard, monitor, and tape storage, I opted for that instead.

[@jimlawson629]

Great video Dave! I know it's back together now, but I would consider changing all of those electrolytic capacitors. Having AC ripple on the supply could cause some interesting problems.

[@joinedupjon]

Glad you took the appropriate safety precautions (checking wife was out) Looks like some of the PSU electrolytic capacitors have already been replaced - might be worth replacing them all TBH or at least checking to see if any are bulging - they don't age well compared to the other components.

[@eDoc2020]

I noticed the two different capacitors but then figured they were probably different voltage for the other rails. 1970s electrolytic capacitors are pretty reliable.

[@jrkorman]

I started USAF Basic training in Nov 1974 and then on to electronics school at Lowry AFB in Denver. I started a subscription to Popular Electronics with my new found "wealth" and the first issue I received was Jan 1975 with the Altair on the cover. I was hooked. It would still be several years before I got my first computer, a Radio Shack Model I in 1980. Hope to see more of this beast as the first one I saw was in 1977 out in a computer shop in Albuquerque. Some of the guys were trying to get code running to access an 8 inch disc drive.

[@RY-TIOUSRY]

great stuff Dave. you do it ALL man.

[@JPBennett]

I was recently introduced to the q1 computer, based on the 8008. Probably led directly to the Altair, too.

[@mwestcc]

looks great - nice job and video

[@andrew2004sydney]

Awesome video! Maybe make some videos showing and telling us about each PCB inside it?

[@matthewJ142]

I always had a fascination with the mechanical side of PCs more over than the programming side but I love both of them just the same. Just wish it was easier to understand

[@mercster]

Very interesting project, thanks for the video Dave!

[@DennisKyne]

Hello from Gig Harbor, I love seeing these ol computers. My first was an IBM XT no turbo but I upgraded with 1mb memory card for about 300 bucks.

[@mhoover]

I built mine in 1975. It launched this college dropout from file clerk to systems analyst in a couple years. Thanks for the memories.

[@Backyardinstallers]

Perfect openinggg... D'oh!!!!

[@martinhaub2602]

Thanks for the trip down memory lane! Computers were so much fun back in those early days. Kids today have things like Raspberry Pi to play with, but building a machine from a kit and having it actually work was a thrill beyond words. Hope all those machines wind up in a museum someday for people to ogle over.

[@scsirob]

Nice one, Dave! FYI, the serial board is likely to require +8V and -8V, as the RS-232 standard needs those. Next-generation circuits use ST-232 or equivalent level shifter chips that internally convert +5V to +/-8V for correct signal levels.

[@UncleKennysPlace]

My father washed all the guts of an expensive piece of technical equipment at his first week of work. Everyone was aghast, but he just noted that it didn't work, what was there to loose? He washed everything, oven-dried it, and a machine that cost as much as a house fired right up. I washed the guts of a digital camera that fell into a pond, and cleaned the optics; still have it, works fine, though now it's a "vintage" item.

[@ChrisSmith-tc4df]

An Altair 8800 very similar to that one was gifted to teenage me in the 80's as it was already obsolete. I messed around with entering simple assembly language programs into it for a couple of months, but ultimately decided to scrap it. I still have the front panel switches, transformers, and fans. As a teen, it was hard to imagine it becoming collectable given the onslaught of much more interesting machines.

[@PeterScargill]

Nice trip down memory lane but US focused. The first home "computers" in the UK (we were not able throw as much money at this stuff) included the Sinclair SC/MP.. a computer with no stack. Nearly put me off computing for life. The Z80-based Nascom 1 restored my faith and I eventually expanded into a full, boxed PC.

[@MrJgsmith]

Amazing video. Thanks for sharing with us.

[@diskgrind3410]

I had a friend in the late 80's earl 90's who bought computers from estate stales. i loved checking out how this stuff worked. Loved it.

[@volmarrwyrd]

When I was a child (born in 1972) my father had one of those in the 70s, and I used to watch him building and tinkering with it. We went on later to have all sorts of different (what now would be considered vintage) computers. Wow watching this brings back memories!