EEVblog 1419 - Sinclair C5 Restoration - Part 2 

Body likely would be nice if you got it all cleaned off with some sugar soap and water, followed by a polish with some automotive buffing compound, and then a final going over with paste wax. Will give it a much better finish, without taking too much off other than the oxidised paint top layer. The wax will then protect it further. Anything more you will need a bumper repair shop to strip it down, do a proper primer coat, then a few topcoats of a flexible paint, and then a final clear coat over it all. Black inner and plastic parts simplest will be to wash it as well, then get a bottle of pure silicone tyre and bumper polish, and apply liberally, though note it will make them hydrophobic, and incredibly slippery, and for a while, till it soaks in, a dust magnet. The silicone can be wiped over the entire vehicle as well, it will do a good job of preserving it, though not a good idea if you ever intend to repaint it, as it will be hard to remove, and will cause the paint to fish eye all over. Chassis needs to be stripped out, and then reinforced with a bit more steel where the original spot welds have cracked, preferably using a rib that fills the entire length, and which is MIG welded down all the way. Then cleaned off, rust removed with rust converter inside and out, and the inside liberally sprayed with linseed oil, after you have sprayed the outside with a coat of grey primer. The linseed oil will fill in all those tiny crevices, and polymerise, so the metal will not rust further. Very likely the gauge unit does not work any more, those Ferranti ULA's were not exactly known for being a reliable part. Incidentally I still have a Sinclair amplifier kit, complete in bag, with the original no name branded reject Mullard transistors that were used in the kits, as they were available for scrap metal prices, and Sinclair would simply test each one, and those which had the faintest bit of life, some gain, and minimal leakage at 12V were then used in the kits. Might not work at 30V, but will not fail immediately with 12V, and anything with a gain over 2 could be used. If I ever build it it would need all new capacitors, doubt the originals are any more useful other than as a space filler on the board.

Would love to see this thing restored, especially with modern electronics. Hope you continue the series.

nice to see the C5 getting some love!... RIP Clive...

Oh no! Clive passed away! RIP. The ZX81 was what got me into this field that I'm plugging away at all these years later. I assembled the ZX-81 kit and will never forget how proud I was as a young teen in Africa watching this thing boot for the first time with that flashing cursor. Thanks I guess for the sad news, Dave.

RIP Sir Clive. What an industry titan!

* 9:59 - Remove that rust. Wire wheel on a drill. Then toss some self-etch primer on it. * 11:01 - Chain needs some lube badly. * 11:17 - that frame looks split. Needs tig welded back together before you start taking it out * 13:18 - wheel support thing is toast.. no repairing that. Trace it on paper to get the dimensions before it gets more broken. Use some calipers and measure shape / depth, etc. Give to a local machinist to make up a new one. * 13:31 - Those plastic belt gears look really brittle... * 14:22 - A great time to use an impact wrench to knock those bolts loose without holding stuff It looks like a lot of work. You'll need a bit of tig welding, some paint + grinding, and some custom fabricated parts. I'm sure a lot of stuff was plastic to save weight, but plastic doesn't age well in critical pieces. Replace anything in the drive train with damaged plastic with metal, and convert to a chunky Li-Ion / LifePo4 for the batteries. The denser energy will make up for the weight gain.

The frame is cracked, where you asked if "is this due to rust" No - The welds have split, and it requires a few minutes with a welder to fix.

My first computer was a Timex Sinclair 1000 with a 32k memory addon, so many fond memories of coding simple BASIC programs and saving them to cassette tape with csave and cload. Wow those were the days. RIP Mr. Sinclair and thanks for the opportunities your frugal engineering afforded me.

The C5 was so far ahead of its time, can you imagine this thing with fibre reinforced plastics, AC motors & regen, LiFePO4 batteries, aluminium alloys, bike suspension thats now commonplace. It already looks like the inside of a Tesla. Sinclair had so much difficulty making the C5 a reality with 70s tech (and had to make a lot of compromises), hopefully someday soon someone can make his vision more of a practical reality, Vale Sir Clive, and Thank you.

I have a vague memory of Sinclair C5s being used as advertising hoardings, somewhere near Turnpike lane (London UK). I built a Sinclair scientific from a kit and it sort of worked, contact bounce was a problem, I think the most I got was 4 4s from one key depression. If you squeezed it but slightly during a calculation, the batteries would lose contact and you would lose the lot, not the most reliable device. Reverse polish notation, there's one for you, forgotten how to do do it now. Before he was a Sir, Clive Sinclair released a series of booklets mostly of transistor radio circuits, I'm sure I built a few. I recall him waxing lyrical about the marvellous OC169 transistor, no doubt by now, tin whiskers will have seen most of them off. Thank you, Sir Clive for your enthusiasm ,ingenuity and inspiration to others.

RIP, Sir Clive Sinclair. A true visionary of his time. His ideas and business knowhow helped kickstart the computer industry in the UK and elsewhere. He recognized that the price-to-entry for small home computers was quite high at the time, and knew he could do it more cheaply. The £100 ZX Speccy was very popular here as a result, and many software devs owe their careers to that little machine. Some big names from the likes of Sony, Nintendo, Microsoft, Rare got their start programming simple games on the Speccy in their younger years. I think it's time to watch "Micro Men" (2009) again. One of the best dramas the BBC ever made, IMO. Thanks for all the great memories, Sir Clive.

Must be one of the first times I've seen Dave's hands dirty working on something! Normally the only time is from the canyon climbs or mud runs lol

My first digital multimeter was a Sinclair, It did not last long as it blew up, I took it apart and found that the case was the same as the calculator with a sticky lable covering the spare button holes. I met Clive Sinclair briefly in the 1970's, I was living in Cambridge at the time and a Sinclair amplifier that I had purchased via mail order failed soon after I turned it on so I took it back to his shop in Cambridge and Clive came out of his office looked at the unit briefly threw it in the bin and handed me another off the shelf saying "here you are" and turned and walked back into his office. The motor on those C5s was made by Hover and the frame is the same as the washing machines at the time, replace the motor with an AC washing machine motor and drive from a VFD. Looks like someone cobbled a speed control switch from a drill into it.

Thank you for many fun hours and days Sir Clive. RIP. I had the pleasure of owning and building some of your products, - Sinclair Micromatic pocket radio kit (1967 - 1971) - Sinclair "Black Watch" watch kit (1975) - Sinclair Cambridge type 3, self-build calculator kit (1975) - Sinclair ZX81 kit (1981) My dream computer in 1984 was the Sinclair QL (Quantum Leap), but unfortunately, I could never afford to buy one.

The world lost another pioneer. RIP Sir. You did good. I loved assembling my ZX81 kit back in 1981.

Absolutely you should continue the restoration. You may as well video the disassembly so that you can look back and see how things came apart. It would be fascinating to me to see how you sort out the electrics. Thanks for the video. Appreciated.

Please do continue with the restoration, I'd love to see this come back to life. Maybe a Mr Fusion in the back & a few blue EL wires down the sides - but where would the flux capacitor go????

the sinclair c5 always makes me nurse a semi so 3 physical thumbs up here and an electronic one on screen. my friends parents both assembled parts for these at Hoovers washing machine plant in Merthyr

Good on ya Dave! Big thumbs up for the restoration. Sir Clive would be proud of you. I'll bet he's zooming around in his C5 in the clouds right now

Looking forward to seeing you start the restoration of this 👍

Having watched part 1 again, part 2 is more like a part 1a.

This is basically an electric trike powered by a vacuum cleaner motor. Sir Clive was a genius in designing cheap products. :) May he rest in peace.

Dave, you should do a colab series with Marty and Moog on the Mighty Car Mods channel to bring the C5 back to life!! :-D

Please restore it and use modern equipment. It would be really cool

We call it a mobility scooter now. Loved his flat screen 90 degree (?) deflection CRT TV !

R.I.P Sir Clive. Glad you were here.

16:02 they were made at the Hoover factory in Merthyr Tydfil, Wales. The factory actually made washing machines! The motor was apparently derived from a washing machine motor

I had a Sinclair "kit" LED watch in around 1978. It didn't keep very good time, but it was fun to have electronics on my arm.

At 6:57, you can see the "spare" tire is Sinclair branded, so it's probably original, and the BMX-type tires that are on it are aftermarket.

Amazing and challenging project. I really wish to see more of it. Thank you very much for your work!!

Looks like it's more for "mechanical engineer Dave" :) he he : ) thumbs up for the Sinclair, inspiring guy :)

This thing would be a great success, with the current craze about bikes and electric vehicles. Someone should make a new one; it should not be forgotten.

Usually easier to release the cables at the lever end - slacken off any adjusters, pull the cable outer from it's seat on the lever and remove the inner cable by manoeuvring it out through the slot in the lever body and then a similar slot in the lever handle.

At first i was thinking spinners for the wheels. But led spinning bar that makes a picture of Dave's logo as he goes down the road. cool.

There may not be enough weight on the front end to work well with a front hub motor; the front wheel could slip if full power were applied. The C5 is basically an adult version of what we here in the States called a Big Wheel in the 1980's. This toy was horribly designed in terms of locomotion as it had a big wheel in the front with pedals, but no weight and thus no traction as the kid sat near ground level above the tiny rear wheels. It probably worked better for city kids with sidewalks, but us country kids despised them after about 5 minutes of trying to make them go. They were mainly just used for rolling down steep inclines as the low center of gravity made them much more stable than a traditional tricycle. Unfortunately, the plastic chassis didn't hold up well to such abuse.

After they were mainly withdrawn or banned from the roads, I believe an entrepreneur used to rent them out at Blackpool beech to wizz up and down the promenade on.

I absolutely adore the design of this thing honestly. I want one.

That bodged in trigger switch looks very much like one from an electric drill. I bet someone converted it to pure electric, instead of pedal assist.

Good old Clive... married a lap dancer from String Fellows and believed the internet was a distraction... Had years of fun with my ZX Spectrum... RIP.

Usually Dave puts in a link to the old video, part 1. Seeing as this is part two. Anyway here it is: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-VCUdDe0t7YM.html

It's been a while - glad you're back on it.

as a professional auto body refinisher im just itching to take on that project.. it would take me 3-4 hours to do it!! just like a normal bumper on a modern car :)

Gave three thumbs up for a full restore series.

I remember over taking a guy (riding / driving?) one of these just after they came out on the A350 while I was on the way to work in Poole. He had the custom yellow cape on (extra cost option) that went over your head and sealed over the C5 body to stop your legs getting wet. He was having to peddle it up the incline in the road and was causing a traffic tail back as drivers had to over take on the opposite side of the road. Being rural Dorset there was (or is for that matter) no cycle or foot path and his head was at the bumper and exhaust pipe level of the rest of the traffic. The poor guy looked wet, stressed and thoroughly P.O'd

I am absolutely in favor of a full restoration. It might even induce me to becom a patron.

And now every day I see pedal assisted bikes on the road, granted with better viss. How many would love to have one of these to fix up with new tech.

7:48 I was taught in school that this stuff is called Corriflute, which seems to be a trade name for it

I'm looking forward to this series.

I'm very keen to follow this project. As others have said, you'll have to get the chassis worked on. Maybe it's just worth beefing it up a bit if you know someone who can weld and just copy frame with box tube or something. In Part 1 you suggested hub motors. A modern bicycle mid-drive motor is probably a lot better with a bicycle sprocket for gearing. Hub motors tend to be geared for limited speed to be able to give you enough torque, where a mid-drive uses the gearing of the bicycle sprocket. Also a front hub motor could tip you over if you hit the throttle by mistake. Don't worry too much about regen, it's so light that it won't significantly increase range unless you load it with batteries.

Looks like some straight of out the original Tron movie, love it

Omg you are finally getting around yo this! I remember when you posted the part one of buying it around 5, maybe 6 years ago? Glad to see it finally is bring worked on!

RIP Clive Sinclair. ZX 48k brought a lot of fun to my childhood.

Prolly said a dozen times, but those transistors and trigger are from an electric drill - a speed control instead of the switched original.

This is rare enough that it deserves a proper, thorough restoration. Ideally, it should be disassembled, the frame rewelded and painted, the drive gear replaced (either find one from a parts "car" or machine a new one from nylon or even aluminum). The front wheel probably needs to be sand-blasted (find someone to sand-blast all the big pieces). The wiring should all be replaced (personally, I would try to match the original components and wire colors) and the motor should be disassembled and cleaned. The bearing may need replacing, too. Most of the nuts, bolts, and washers can either be wire-wheeled or just replaced. Clean and buff the body and apply new reflective tape.

An iconic piece of engineering history. A restoration project looks tricky given that it was cheaply made out of the factory. Good luck 👍

Back when you first showed your C5 I was so fascinated with that I had to get one. I was living in China at the time. I have bid and won an UK auction and arranged a transport to Poland just as I would get a car so the whole thing cost a small fortune to get and it was completely sight unseen :D I first saw it about 6 months later. We had some fan with it, even took it to an electric vehicles gathering. I was planning to do some restoration and mods as well but just like in your case it was sitting in a basement for all those years. Oh man, I did not know Sir Clive has passed away. He really was something and although he apparently had a tough character I admired the man in a way. I think now I also should get to it then in his honour. Especially I believe I still own the only one in Poland.

I appreciate sinclair for the zx spectrum. He is a genious.

Ah this is such a cool piece of history! It's really quite an elegant overall design. Seems like it shouldn't be too difficult to drop in a new motor, modern controller, and modern charging system and have quite a spiffy little ride. Then again, this is giving me dangerous thoughts about building one from scratch... Looking forward to seeing what you find under the covers!

I always liked the Start Trek TNG era shuttle design :)))

Dave, as a fellow electronics engineer I'm going to tell you right now that you'll need to invest in a lathe and a mill :-) I realised I couldn't avoid it so gave in.

Gotta love that "shazzy"!

The C5 was built in the Hoover washing machine factory in South Wales. Considering how people are now running around on electric scooters, an updated version might do well today. I bought a Sinclair Scientific calculator and the first seven they sent me were dead out of the box. Very disappointing for a teenage boy! The eighth worked well and I was the first boy in my class with a calculator - even the maths teacher asked me to check his results. It took several seconds to calculate a log or trig function. It used RPN - reverse polish notation and calculated to five digits plus two exponents. But it cost £25 whereas an HP was £200. Happy days!

I can't believe it has been 8 years since I watched the first Part.

It would be really neat to retrofit the modern disk brakes onto this thing as well, as well as any other safety/comfort features that may have been missing back then, and because of the price. My suggestion - electric speedo/dash cluster of sorts, disk brakes, comfy seat with a belt, and obviously a decent multi-horsepower motor with a solid battery; I bet you can have a solid commuter thats actually usable and moving at speeds up to ~20-25MPH. Maybe even a differential, since there are two wheels in the back, but that would be pretty tricky!

can't wait to zoom around in one of these in the comming 2000's

The motors developed/used in the C5 became available pretty cheaply after the project failed. They became a favourite for use in ‘Robot Wars’.

Yep. They were built at the Hoover factory in Merthyr Tydfil in South Wales (old rather than new) here in the UK. My first programmable portable device was a Sinclair Cambridge programmable calculator. If I remember correctly it had just 34 possible program steps. Ate 9V batteries quicker than I could afford them whilst still in school.

"And for those who don't know Hoover - they make Hoovers." Comment made my day!!

Sinclair's products are fascinating, but simultaneously I also don't get why it's fascinating. From an outsider perspective he was just a clever salesperson with a bunch of products which have all since fallen into obscurity

Great Video Dave, As a side project, you could build an electrolysis tank to remove the rust on the chassis, see what you're left with..

First Hoover that doesn’t suck

Those drain holes in the seat will be useful when a truck passes you. Sadly too far ahead of its time - It probably would sell well today.

I think Sir Clive would be happy to see this restored in any form. Rear wheel drive with a treadmill motor and LiPo battery might soup it up a bit!

My first computer was a Timex-Sinclair 1000. RIP Clive.

Sinclair was a man 30 years to soon, his electric bike kits are relay cool to.

I remember being at school in 1987 and wanting one of these C5s, I so wish I had ignored my parents and bought one.

"If you don't know 'Hoover', they make 'Hoovers'". LOL!

Please follow through and finish this project.

Defo would love to see a series on this! As others have said, modern e-bike gear would be a great fit and pretty cheap.

RIP Sir Clive. I’ve still got two ZX Spectrums 48 with 001 serial numbers. My precious….

my back hurts just looking at that handlebar positioning.

I a Good c5, and love to watch You Restore this...

0:48 Oh! That is a shame to hear, that he has died. Though, I thought Sinclair was just a company name, and didn't knew there was a person behind. My mind goes weird places sometimes. For robots (and machines) RIP can stand for Rust in Pieces ...

RIP Sir Clive x 1st computer I ever owned was the 16k Spectrum

This little buggy is so cool! I bet that they had to put pedals to avoid some regulations, as e-scooters with pedals. So that it could be used without a drivers license, just like a bike, unlike a motorcycle.

Please, Dave, continue to do the restoration and also look at updating it to more modern electrification to see just viable it would be today. I know that there has a bit of discussion about the passing of Sir Clive on the EEV Blog TEA section, with most people poking fun at the great man's products, which is a real shame. I firmly believe that there are many people in the industry and hobbyists today, who were inspired by his kits and products, he certainly inspired me. I still have a heavily modified ZX Spectrum with a proper keyboard and also a Sinclair Scientific calculator built from a kit and maybe one or two other items in my garage that are still working today.

This deserves to be restored properly to respect Sir Clive. All original parts, does not need modern technology as I dare say you won’t be using it as a serious commuter.

It may have been rejected as a product, but the idea is a wonderful solution for personal transport...too bad we don't get it. Long live Sir Clive Sinclair.

4:28 - The handlebars have been rotated to sit further forwards than before. This gives better turning circle. 12:27 - the hoop should bolted through the frame. 13:13 - the back of the wheel shouldnt have come off. There shouldnt be that many washers too. There should a washer behind the large pulley though. 14:06 - Yes one side is 16mm and the other 17mm. 16:14 - pads look fine. Setting up the arm at the right point is key. It can go between not working at all and locking up with the slightest touch :) Any questions or parts get in touch :) As others have said the frame is cracked and will require fixing. The same thing happens if you put more than 500w through it. The most common mod is to run 24v through the original motor and find an ESC that can cope with at least 120-150A max. Cooling is essential and Ive got a guide for that. Remember to service the motor and gearbox completely, polish the commutator and grease the gearbox with non-lithium based grease. 18mm drive belt is an upgrade if you are retaining the original motor. In terms of cleaning it up... "elbow grease" works wonders or "the pink stuff". There arent replacements for the headlight stickers or your serial number so dont wash them off! For frame painting canbrush C16 pale grey is an exact match.

rip clive. loved my 48k speccy. i remember being amazed with jetpac at the time.

Wild idea: live stream the mechanical and electrical repairs of this Sinclair C5?

All these years, not sure I've seen Dave using a wrench. 👍

Blimey! Was it eight years ago or something like that you tinkered with it the previous time?! Well fitting tribute to sir Sinclair for sure! I hope you gut it and source a modern electronic motor, controller and batteries to both make it usable and to prolong its life for another decade or two... The 80's was a mad period and few looked at making things as cheap as possible but Commodore comes to mind as well, albeit a bit more well funded but not as radical, but both still have a huge following today! Modern electronics gizmos (as this would correctly be labelled imho) wouldn't have lasted a fraction of the time like this has or the same era computers vs. the ones made today, so perhaps the 80's was the last decade before we stopped repairing stuff and instead only replacing everything that develops a fault... :( Waste, waste, waste and waste. Anyhow I'm glad you've resurrected this old C5 and I hope it's not another eight years until you mend it, but if so I'll be still watching it!

PLEASE CONTINUE

RIP Clive - make him proud Dave!

That long handlebar bolt holds a split wedge in the tube. You shouldn't take the bolt out like that or the wedge can fall to the bottom where it can be tricky to retrieve. The right way is to loosen it a few turns, tap it to dislodge the wedge nut, then pull the whole lot up out of the tube. I recommend you carefully replace that bolt by hand taking care not to push down until you've caught some threads.

I'm very much 4 a full restauration! It fun for shure.

Id love to see one of these built with modern electronics, motors, and batteries. I expect stuff developed for e-scooters would be readily usable!

The Hoover headquarters is located near my house and I worked on their boiler system . They were located in North Canton Ohio. I now live in West Virginia but I may do some bumming around and see if they might have a few parts or three on a shelf. Hoover was well known for making every part on site ,so there maybe a chance.

I didn’t know you had one of these! That thing is awesome!