Restoring and Exploring a 1981 Sinclair ZX81

The sinclair ZX81 from 1981 is an iconic retro computer in the history of home computing. The follow up to the ZX80 Sir Clive Sinclair consolidated many chips into a ULA to further cost reduce the computer and help get it into our homes from under £50. A truly low cost computer. Today we take a look at one, repair it and try it out to see how it holds up today.

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00:00 Intro
02:21 Who are PCBWay?
02:36 Exploring and repairing our Sinclair ZX81
12:48 Testing the ZX81
14:40 Our thoughts on the ZX81

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#sinclair #RetroComputer #Restoration

[MalcolmCrabbe]

Oh this brings back memories. I would purchase ZX81's in kit form form WH Smiths for £49.99, build them, and then sell them as new for £59.99, which was £10 less than the £69.99 WH Smiths were charging for the build versions.... Earnt enough for my first holiday the following year :)

[darranstyler]

I had one for Christmas in 1981 at the age of 10. 40 years later I have a career in IT spanning a quarter of a century, and more importantly still a massive geek 😊

[giovannip.]

A friend of mine got one for Christmas way back when. He got into programming and got me inspired to learn. It lead me down the path of buying a Sinclair QL - not too many kids at the time wrote school work on computers back then...

[colinsmith]

This was my first computer, which i got for Christmas in 1981, and spent the next week hassling my parents to use the tv for the computer, I ended up using all my Christmas money, and help from my dad to purchase a second hand B&W portable tele so i could use ii in my room !

[TwpAcPr]

Still have my model 😋 mint condition in the box, I bought mine when I was 10 with paper round money 💰 thats why I've looked after it so well, hard earned money

[CooChewGames]

The ZX81 was my first computer and the only reason we could ever get a computer... an amazing piece of hardware that still really kicks in the nostalgia like nothing else does.

[skyhawk]

My first ever computer at the age of 4 (1981) and still have in my room today. Fond memories as I came home from playschool to play Space Invaders and an another side scrolling shooter game. In 1985 my brother and sister bought an Atari 800 XL which was an awesome machine I used for many years up until 1992 and still have today also.

[Roblilley]

The ZX81 was my first home computer, it was actually a ZX80 that had been upgraded. Loved to use the 16k ram pack but always careful not to knock it as they always crashed easily. Lovely memories. Thanks Guys

[roygillotti]

I recently had a fairly big project restoring mine recently, I found it sans casing and keyboard in a box at my Parent's house when cleaning things up. Decided to make a 3D printed casing and a keyboard using MX cherry key switches, found some ZX81 keycap stickers. Replaced the 7805 regulator to a more efficient switching type which allowed me to lose the large heat-sink, Upgraded the memory to 16k internally using a hardware hack I found online, gave it Composite video with a slighty different mod than the one you guys used. I could have easily just bought one for cheaper than all the work I put into it, but this was literally the computer that sparked my interest in computers, so felt it needed a little love.

[tommylakindasorta]

"They can go into storage for when the world switches back to RF."

Now I know what a true retro enthusiast dreams about at night.

[oceanbint]

I know a few people are saying they didn't like the banter but I enjoyed it. Great video guys.

[garyjohnson]

Way back in the 80's when I got my ZX-81, I opened the case and immediately modified the RF modulator turning the video output into composit. It worked great and it lasted for a very long time.

[zBijs]

RIP Clive Sinclair. Thank you for all Sir !

[MikeMcCollister]

Great restoration and review. As I live in the US I had the Timex Sinclair 1000. It is basically the same machine with NTSC and 2 KB or RAM.

There were two issues that I was able to fix:

1) It was famous for overheating so I went to a local metal shop and got a new heat sink created that is twice is long. There is plenty of space inside the computer and it made a significant improvement.

2) The RAM pack wobble was fixed by going to the same metal shop. I had the man cut down a sheet of stainless steel, not quite as wide as the expansion port. It was bent so that the stainless steel extended to the bottom of the chassis and was riveted on it. There was a small bent part that went inside the chassis about 0.5-1.0 inches that acted as a tension spring to hold the expansion module steady. I do not have the machine anymore. I hope that this explains what was done.

[AndreasToth]

My good friend had a ZX81 and soon got himself a ZX Spectrum and these devices were my introduction to computers and programming.

[MatthewJohnCrittenden]

ZX81 started my interest in computers and a Software Engineering career to continues to this day. My Dad made a wooden clamp to hold the RAM pack still. RIP Sir Clive.

[gramar]

I remember being so happy when the taped program actually loaded correctly and being frustrated when the memory add-on block would fall off and everything died, but it was my first computer and there wasn't anything better that I could afford

[mkaushik]

I got a ZX81 from a distant relative when I was a kid. It didn't work, and all I could do was peer at the components in amazement. Years later after all my engineering degrees, I remembered the ZX81 and realized I had the skills to fix it myself. But I could never find it at my parents' house. Watching this video brought back bittersweet memories :sigh:

[mEnTL]

RMC with a ZX81 thumbnail. Be still my heart

[resrussia]

ZX81 was the computer that got me into computers. I saved my $150 for computer, 16 KB RAM and some games. I ended using the computer mostly for programing in BASIC and machine language (yes, I poked numbers representing instructions into memory locations individually). I was a finalist in a science fair creating graphical represent of the gas laws (the user press keys to move a graphic of top of piston to increase or decrease the volume and the screen printed out the pressure in the piston) and simulation of a virus attacking cell. Thanks for an excellent video.