You Won't Believe What's Inside These! (Actually You Probably Will)

Tearing down a Commodore PET, Commodore 8050 Disk Drive, IBM 5160 PC XT and a couple of IBM 5170 PC ATs to see what's inside!
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Outro: Yomoti - Before Chill
Chapters:
00:00 Intro
01:14 Commodore PET 3032
05:35 Commodore 8050 Disk Drive
07:47 IBM PC XT 5160
17:42 IBM PC AT 5170
23:59 Another IBM PC AT 5170
27:59 Outro & Thanks
#retrocomputing #commodore #msdos

[@paulmckeown5672]

Ancient undisturbed parts of my memory woke up watching this. I can remember opening these up back in the 80's

[@paulstubbs7678]

That AT chassis looked so familiar to me. I used to work in a Telco repair shop fixing PC's, modems & Telex machines.

[@vwestlife]

The IBM AT also originally came with a decorative black plastic cover for the rear, but most of those got broken and lost decades ago. The drives have grounding wires because they're attached to the case with plastic rails, so they don't get directly grounded to the case like in other PCs. As for the CRT in the PET, by the late '70s small monochrome picture tubes were pretty much all electrically compatible and used the same pinout, so as long as you find one that fits in the case, it should work fine.

[@ctrlaltrees]

Well that's all very useful, thanks for the info. I've never seen one of the black plastic rear covers, I shall have to keep an eye out. 🙂

[@TheErador]

Surely they could have been grounded via something on the ribbon cable or power connector !

[@stevetodd7383]

No, the PET isn’t an early model. The first release was the PET 2000 series with a chicklet style calculator keyboard (which was horrible to type on) and a built in cassette drive. From memory they came in 4 and 8K sizes. The 3000 series fixed the keyboard (requiring the cassette drive to be moved externally) and moved to DRAM memory thus allowing 16 and 32K sizes. People worked out that it was cheaper to buy a 16K model and add the extra 16K of memory yourself, and Commodore stopped that by drilling holes through the motherboard.

[@KoolBreeze420]

These bring back memories from my childhood. The first computer the Commodore shows why screensavers were invented.

[@Oil_of_Hope]

I do love the look of the commodore pet, just something so 60s and 70s sci-fi. Almost expecting Arthur C Clarke's face to look back at you from the monitor..

[@w9gb]

I saw an ALTOS 986 (10 MHz, 8086) in the pile of computers. 40 years ago, when in Graduate college, that computer with a “new” 3com Ethernet (10-Base-2) add-on card was setup as a 3Com File Server (Xenix? OS + 3Com software) for Business school laboratory. The computers attached to that Ethernet network were IBM PCs (PCDOS 1.1 or 2.0) with 3Com network cards. As I remember, SuperCalc and Wordstar were 2 applications. Lotus 1-2-3 eventually appeared. == IBM 5160 was my first computer, acquired from an IBM dealer w/o 10 MB hard drive. The original hard drive had failed, and was exchanged with original customer. Cost at that time (1983) ?? $ 1500 USD for that IBM XT; then 20 MB hard drive ($1500) which was added; plus $100 for Hayes Smartmodem 1200.

[@DavidSiebert]

My school had 6 SuperPets and two 8050s with Muppets (SP?) that allowed the Super Pets to share the drive. The SuperPet had an extra board holding a 6809 and Pascal, Cobol, Fortran, APL, and Assembly. Pretty exotic stuff for 1982.

[@senilyDeluxe]

From my experience, the PET power supplies are quite reliable and the only thing that explodes on them (but it does that quite reliably) is the input filter capacitor. The 8050 has it integrated into its IEC power socket. These huge soda can capacitors are usually fine. I've seen charred pins on the power connector in one case, which made the machine unstable, but a new PSU is not gonna fix that.

[@ctrlaltrees]

Interesting, that's useful to know thanks. It would be nice to keep it as original as possible - of course it will be thoroughly tested.

[@jameshearne891]

The connector on the 5160 floppy card is for an external drive, you could have up to 4 floppys on those systems. And the yellow bodge wires are factory on some 5160 motherboards.

[@tw11tube]

To be exact: The connector on the 5160 floppy card is for *two* external drives. With those IBM controllers, you can only connect two drives per cable: Two internal drives to the card-edge connector at the "rear end" of the card, and two external drives to the 37-pin D-type subminiature connector on the slot cover.

[@markpitts5194]

@@tw11tube The dreaded IBM twist. They just didn't trust us to set the jumpers, like we had to for EVERY other setting in the machine lol. Remember the days of squared paper, working out what IRQ DMA and address we could squeeze everything into?

[@IanSlothieRolfe]

You didn't mention or didnt notice the 8050 disk drive has a 6502 processor and is in fact a fully working computer - you could upload code to it and execute it. There were a few database applications that made use of this function.

[@daffyd5489]

Nice, all the peripherals were connected with the IEEE-488 bus, which was a widely popular standard in industrial applications at the time. I remember using the RML-380Z computers using this in college in the '80s, then using the PET (and HP controllers, oh, and even the Sinclair QL had an aftermarket IEEE-488 interface board)) to control equipment (Racal, HP, etc) and various other test equipment in the early '90s. Now it's all USB, but I think you will find that the underlying protocols used are still very IEEE-488 in many instances.

[@ctrlaltrees]

Ah! I'd actually heard this rumour about an old disk drive but didn't realise that that was what I have here. Definitely something to investigate - thanks! 👍

[@RetroBytesUK]

The original idea was multiple pets could all share the drives by connecting them all on the same 488 bus.

[@iainlaskey7285]

Not sure if true but back in the day I was told these drives could load code that effectively made them able to copy protected disks, almost like flux copiers today. Allegedly these could copy Atari 800, Apple etc games.

[@neilloughran4437]

The Commodore PET was the first computer I ever saw/used back in 1980 or so... we had a few of them at our school (I think 8k models) in Barrow along with Tandy TRS80s.

[@livefreeprintguns]

Hey, it's ctrl-alt-rees I hear all the time on Retro Action's channel... glad I found you! Subscribed!

[@kingforaday8725]

Something that may not at first sink in. The hard drive was 10 MB not 10 GB!!!!

[@ctrlaltrees]

10MB should be enough for anyone!

[@pigpenpete]

I went to the same jumble and i'm still working through my haul of stuff! Done the compaq 386 with a full recap, fixed up another compaq P3, working on an XT now and have 2 compaq portables in storage still

[@DaveVelociraptor]

There is something really appealing about these big heavy machines, especially the industrial styled ones like the Pet and IBMs.

[@datassetteuser356]

Some nice machines you got there. Looking forward especially to the restauration of the CBM 3032 and disk drive. Can't really read the burnt-in on the CRT, but no matter the language, it's probably not something you'd like to look at. From time to time, these monitor "tops" of the CBM series pop up on ebay, but I guess the mentioned replacement you might get is the quicker way to go. Cheers!

[@ShaunieDale]

The good ol' Pet, the first computer I had any hands on experience with.

[@EgonOlsen71]

The burn-in may indeed be german. I can make out "Gesamtmenge" (total amount) and "Satz" (most likely "set" in this context).

[@AlistairBrugsch]

Best bet for a replacement keycap at this stage is probably to resin cast one

[@dbingamon]

The Commodore 8050 drive which connected to the PET uses IEEE-488 parallel communication. The drive controller has its own 6502 Microprocessor.

[@enginecrzy]

Evaporust will work on the rust stains blooming thrugh the paint on your Commodore PET. I dont know if its readaley available in your part of the world tho. It will not affect paint & is non toxic & is gentle/ not skin harming. I soak paper towels in it & apply it to the affected aeria & then cover towels with plastic wrap & magnents for it to stay damp for 1/2 hr or longer if needed. The stuf works Amazeing!

[@dennisrecla3974]

That is a later model PET, the original that came out in 1977 had what they called a chicklets keyboard, it was NOT a full size keyboard and also had a built in cassette tape player/recorder.

[@BarnokRetro]

What a nice assortment of 80s goodness. Lot's of fun to be had with that group of computers. I was always a Commodore guy back then, but there was a guy down the street who was into the PCs and I got to see them through him. He was a work from home software dev in the 80s! Anyway a lot of memories of the PETs at school and the PCs at Ken's place were dusted off today. :)

[@AntonyTCurtis]

The piggybacked DRAM chips in your second 5170 is worth showing people as it's an oddity which people wouldn't expect.

[@RetroBytesUK]

Nice collection of machines you picked up. That restored AT case looks to be in great condition. Hopfuly you will be able to find a nice isa video card to go with each of those IBMs.

[@tiemanowo]

It is really interesting that expansion cards in this IBM 5160 looks very clean but cables are filthy and case is rusted.

[@bitdigital8052]

I just noticed these Commodore Pet's and Original AKAI MPC 60's have a few things in common.

[@jeffreyjoshuarollin9554]

The 5150 was the original IBM PC (the model number was chosen to insinuate it was in the same line as the 5100, whose name escapes me - DataMaster? - but which also had an Intel CPU). The 5160 you have there was the PC XT, which (allegedly?) stood for eXtended Technology.

[@martinhow121]

The 5100.5110/5120 had a 16 bit Palm Processor, which was a S/370 microcode emulator(ish) no connection with Intel.

[@jeffreyjoshuarollin9554]

@@martinhow121 yes, you're correct about the processor. Thanks for that.

[@Zeem4]

The Datamaster name relates to the IBM System/23 Datamaster (models 5322 and 5324), which used the Intel 8085 CPU. The 5100 was just called the 5100.

[@Thaifid]

I remember first seeing a commodore pet computer when I was a young child in grade school, probably in the mid 80's. (85/86) They were still using it for educational games from time to time, but the teacher treated it like a religious obelisk, and kids were rarely allowed to go near it. So it just sat, mostly unused. I was always very curious about it, one day it was being serviced, and they opened it up and I was awe struck!

[@davedave9308]

Great stuff! Most enjoyable. The PET external floppy drives are no more redundant than the PET itself or any other vintage computer. Personally I would get more satisfaction from restoring the drives to working order and using them rather than using a modern SD card, but that's probably just me.

[@catriona_drummond]

So much AT goodness. Looking forward what will happen to them - always on the look for some inspiration for my own 4 AT's and a 5th trash-to-treasure-candidate-in-parts one.

[@Chris-yc3mm]

Really wanted to go to that sale before the musuem opened, but ended up ill 😢 glad you got some interesting stuff play with

[@r.kellycoker9387]

PET = "Personal Electronic Transactor" The most scifi name ever!

[@tw11tube]

You are right that there is the 5161 PC Expansion unit that can be connected to a 5150 IBM PC, so you can add a hard drive controller, a hard drive, and possibly some I/O cards. The 5161 has a passive backplane, and 8 slots in the same layout as the IBM XT. There is a pair of 8-bit ISA cards, one to be installed in the 5150 and another one to be installed in the 5161, connected with a quite thick cable. The plugs for this cable are on the slot cover. As far as I know, there never was any official IBM 16-bit expansion solution. And if there was, it wouldn't have been connected using a cable through that feed-though, but using a regular connector on the slot cover. The piece of metal with the hole is not original, at least not in that state. The 5170 has a battery door for the CMOS backup battery at that location.

[@weepingscorpion8739]

If all else fails with the PET and its keyboard, the 8-Bit Guy and TexElec made a replacement keyboard with Cherry switches for the PET. It should fit your model too. Those were some lovely machines indeed.

[@andykendall5171]

No powder coating in the late 70's. Good old spraypaint😂

[@ctrlaltrees]

Oh I hear ya! But I think powder coat will be closer to the original finish (as per the IBM machines) and harder wearing than I could ever achieve with rattle cans 😅

[@sweetlilmre]

​@@ctrlaltreesjust had a pc case sand blasted and powder coated. Definitely recommend.

[@gingerhippygaming7962]

Great video mate

[@TimberwolfK]

I'm fascinated by the "maxed out" XT - I wonder if it was built like that or if it's one of those situations where someone had it when this kind of stuff was getting thrown out and so they slowly built up an "ultimate" configuration. I remember doing the same with old 486s in the early 2000s and then again with Pentium III-era kit later in the decade; maxing out the motherboards with as much memory as they'd take before refusing to boot. Would be a good one to track down some original software which needs the 8087 and all that RAM. I think there were a few early CAD packages which wouldn't run without the coprocessor installed.

[@a500]

That was a really interesting look through with a dash of history for good measure. Thank you

[@ctrlaltrees]

You're very welcome as always, glad you enjoyed it! I'm looking forward to getting stuck into these. 😁

[@a500]

@@ctrlaltrees yeah. That’ll be nice. I even learned about XT vs AT along the way. Something I remember being a bit confused about in my Amiga years when looking to transition to the PC.

[@YarblekRW]

It took me a year and a half to get a replacement Shift key for my Pet. It seems that the left-SHIFT is often missing due to its vulnerable position.

[@winstonsmith478]

Wow, those are so grungy inside, like they were stored in a coal mine or oil refinery.

[@pigknickers2975]

Always fancied the PET, looks like the Sphinx I think. Keyboard very reminiscent of the Vic20 which I did actually have. That big power cap!! If that went bang you'd know.

[@oleimann]

I always used ISA slot for 16-Bit (286) slots, while the shorter one is ust an 8-bit XT slot. EISA was then 32-bit, around the same time as Microchannel (IBM's choice for patents, most likely). I still have the 8-bit bridgeboard which would actually also work with an ISA 16-Bit VGA card :) Need to fix the AMIGA 2000 main board, though. The PSU had a problem being connected to it, starting to tick. I did get the Batteryleakage cleaned up - it wasn't too bad.

[@BrassicGamer]

I've never tried to acquire a CGA-era graphics card so I don't know whether it would be easy/hard or cheap/easy so I wish you luck! I guess you have the one from the 5150 at the very least. Great acquisitions!

[@Mantikal]

This stuff is great to rent out to movie or TV series productions that are doing time travel scenes.

[@andygozzo72]

i wouldnt worry too much about original power supplies like in that pet, more reliable and less to go wrong than in a 'modern' switch mode thing..take the transformer out , brush it, and gi e a few coats of slightly thinned down solvent based yacht varnish(not water based one)

[@RolandV3922]

Thanks for the trip down memory lane. For the missing key: did you consider a 3D printer ?

[@mikebell2112]

One controller for the drives but it could directly do a disk copy. If anyone is familiar with device 8 and drive 0: the second drive is 1:.

[@TimsRetroCorner]

There's a RIFA cap on the PSU input of the 8050 drive to be aware of - mine went fizz-fizz-pong the first time I powered it up. Also, the single board over the right-hand drive has the motor & head electronics for both drives, you'll see a flying cable go to the other drive. The big digital board attached to the roof has more processing power in it that the PET it's attached to - there are two 6502s in it! Yep, it's a dual-processor!. BTW, grab some spare 6502 chips - they are somewhat prone to die in these machines.

[@markpitts5194]

You are not wrong about the 'pong' bit.

[@crabdonkey6381]

Do you have RS-488 cables to attach disk drives to Pet?

[@dadawoodslife]

Am i the only one shouting at the screen, ' That's not an early PET, it's a layer CBM'

[@gingerhippygaming7962]

Manchester nice will have to go and see this

[@wimwiddershins]

I for one, believe what was in them.

[@Wobblybob2004]

The 5150 and 5160 cases are quite different. The 5150 has a cassette port next to the keyboard port and the expansion cards are spaced differently. So transplanting motherboards from one to the other is a bit of a no-go. 😞

[@ctrlaltrees]

True, but I think the top case should be the same at least?

[@billdavies6463]

6:50 Microswitches for write protection of the floppy disk?

[@paulschmidt7473]

That's actually not a PET, it's a later CBM model... The original 1977 PET came with 4K or 8K of RAM black and white monitor, the chicklet keyboard and built in cassette drive. Around 1980, they added the CBM models, intended for "commercial" use, a real keyboard, green screens, and more memory, yours has 32K of RAM..... The 8050 was a single sided, double density drive, I used to know the command to print a file, without loading the file into the computer first.....

[@brentgoeller8257]

You could send me one of those 5170s. I mean, that's what I would love to see you do with them. lol. But, since that isn't going to happen, Having 2 of those, you should be able to build one awesome fully functional machine.

[@crabdonkey6381]

We had an earlier US unit with the chicklet keyboard. Yours has the better keyboard.

[@dave24-73]

Wonder if Neil from RMC - Cave could help you source that missing key.

[@georgemaragos2378]

Hi, nice older hardware, unfortunately my collection these days arts with Pentium 100 I purchase d new C64, PC XT Turbo clone, Amiga 500, 286,386,486/the P100 etc right up to a HP P4, that lasted 2003 to 2012 as a daily driver Now i also have Pi3b, PI400, Pizero2w and i really want a Pet or classic early mac case and flat laptop screen to make them look older and just run a emulator for nostalgia and reliability

[@MattOGormanSmith]

That's not an early keyboard. The original ones had chiclet keys and a tape deck where the numpad is

[@samio3907]

Just 3D print a keycap, until you find a original one

[@natejgee]

Any spares would likely be accepted by DCM!

[@ctrlaltrees]

Indeed, always happy to help out and that reminds me - I'm actually talking to Rob at the moment about another project. I shall have to see whether he's interested. 😁

[@infinitecanadian]

Please don't sacrifice one to save another!

[@gingerhippygaming7962]

I'd love a pet one day I will

[@colinsphoneemail]

That screen on the PET is not in reasonable condition. It’s burned bad

[@AMPProf]

Candy?

[@markpitts5194]

Anybody notice that there wasn't one video card in there at all ?

[@RetroBytesUK]

Before I start watching my guess is electronics, dirt and dead insects.

[@mrdali67]

I predict a lot of dust

[@jasonhowe1697]

scsi CARDS, since ide/eide didn't exist on the 80's

[@AMPProf]

Switches

[@ogawasanjuro]

You know nothing about the Commodore PET??!?!?!? Argh! In the US it was a classic in the schools when I was coming up.

[@AMPProf]

RAVE COLOR

[@wiwingmargahayu6831]

e waste ben youtube channel

[@ctrlaltrees]

The best part is I actually paid for this junk 🤣

[@T8staDiM3rda]

Looks like you've got the 9.5" screen model for the PET. You won't be able to use the Amstrad GT monitor - physically too big and power requirements are probably higher. You can do an internal mod (or external user port mod) to output composite video. Also, would recommend BitFixer's Romulator to help with diagnosis on 6502 based computers/disk drives. it's very nice bit of kit that can emulate ROMs and RAM. Decent price too. Oh and Stupid pet tricks is a nice project to build to add joystick ports and internet access.