The mystery of the voltage mismatch has finally been solved by Michel (from the channel “le labo de Michel”: www.youtube.com/@lelabodemichel5162 ). Yes, it’s using standard avionics 400 Hz 3 phase 115/200 (115V line to neutral and 200V line to line), so my supply was set correctly. *BUT* it’s not using all 3 phases! It’s using only 2 phases on A and C, and B is neutral! The silly British. We still love their equipment though.

@yankeebotanist4699

10 ай бұрын

Hey curious Marc, I may be acquiring a old 1930s teletype machine soon. It was from a old TV show new station, it does not appear to come with a onboard keyboard, but has a cover and its stand, as well as a bunch of extra plugs underneath the stand. The electronics look like they are still intact. It is from United press international it says on the front of the cover. Was curious if you had any info on these machines and any tutorials or recommended sources on how to fix them. Get them working again in some way. How one interfaces with the device. I have a vintage Macintosh, a radio shack computer that uses color basic, and wondering if those are able to interface with the telatype? Look forward to hearing from you! -yankee botanist

@twotone3070

8 ай бұрын

I expect it was done like that to fox old jonny foreigner should one fall into their hands.

@jjlee69

7 ай бұрын

The power was supplied by the aircraft. I've used these with Hercules C130K which had sockets for using test equipment. I was later using these test sets in the Avionic workshop at RAF Lyneham, repairing Smiths MK10 autopilot until around 2010. Good to see you repairing this one. Makes me feel all nostalgic.

I should go to bed now but its an emergency!

@MrMilarepa108

10 ай бұрын

Same! Thank you for alerting me!!!

@suomi35

10 ай бұрын

Ha ha ha, same!

Early OC71 transistors had the glass envelope painted black instead of the aluminium can. They also had no grease, or transparent grease. Scraping the paint off would get you a more expensive OCP71 phototransistor. Since a phototransistor was quite an exotic component at the time it was a very popular hack with hobbyists.

@Stephen_Heathcote

10 ай бұрын

I remember doing that in the 80's :)

@jurjenbos228

10 ай бұрын

Yes, I did that too.

I want to be Curiousmarc when I grow up.😂

Capsule can be fixed, though you will need to pull it out, and find the leaking seam, and soft solder it again, then open the vacuum port, and use a vacuum pump to pull it down again, then seal the port again with solder. Perhaps one of the viewers has some NOS capsules, as those were used in a lot of instruments in that era, that you can use as donors for there.

@CuriousMarc

10 ай бұрын

Worth a try, but I’m secretly hoping for the viewer with one in his back drawer! That capsule looked very corroded all around, as if it had become porous over extended areas. Might not be as simple as just a seam.

@SeanBZA

10 ай бұрын

@@CuriousMarc Otherwise take out, and coat with a conformal coat of epoxy varnish, and put a capillary tube on it, so that you can use a vacuum pump to pump it down regularly then. A bodge, but will at least hold vacuum for a few weeks while you need it.

@TDOBrandano

10 ай бұрын

Or maybe two similar matching capsules can be sourced from a couple of barometers and adapted. The way the design works it should be fine as long as the two capsules are a close enough match.

From memory, the test set was powered by a rotary inverter type 100 (not sure if it was 100A or 100B as there are slight differences). This provided 115VAC 400Hz phase to phase. The inverter was configured in a “Y” configuration without a connection to the centre tap. This type of inverter when installed in an aircraft usually had phase “B” Grounded.

The content on this channel fascinates me.

Wow,that’s probably Smith’s Industries based in Cheltenham, U.K. I used to work just down the road from them (many years ago (but not as many years ago as this piece of kit)) at a Government Installation.

In our datacenters with 3 phase power, a rating of 208 VAC is phase to phase, not phase to neutral (which is 120 VAC). When you selected 60 VAC, it looks like it is the phase to neutral value. You get the phase to phase value by multiplying by square root of 3. I would guess setting to 66 VAC should give you 115 VAC phase to phase. Spent hours wrapping my head around 3 phase power in our environment.

@CuriousMarc

10 ай бұрын

That’s what I thought too at first! But avionics 400 Hz AC is called 115/200 for a reason. 115V to neutral and 200V between phases. This has been the standard from way before 1960. Unless the British do it differently from the rest of the world. Which would not be the first time! Maybe a former RAF tech could weigh in?

@plutt98223

10 ай бұрын

@@CuriousMarc Marc, thank you for the reply. Something new to add to my cache of 3 phase trivia!

@mlmmt

10 ай бұрын

3 Phase power is *weird*

@mateuszsp8ebc691

10 ай бұрын

@@mlmmt Weird? :) In Europe is quite common. In Poland 3 phase power is quite often delivered even to apartments in flats, to supply things like inductive heating stove. We have 230V/400V 50Hz system with netural line. Although I will definitely agree that electrical distribution system in USA is very, very weird :)

@paulmoir4452

10 ай бұрын

@@mateuszsp8ebc691 When you see a house 20km from the next, with a single HV wire and a neutral running along the road, and a single tiny transformer supplying power to the house, it all makes sense.

I'll leave it to you and other commenters to explore and register the details of this device. However, I'd like to add a comment about the case. It's from a family of hardware I know as the 'R.A.E. Case'. I guess the 'R.A.E.' part is short for the 'Royal Aeronautical Establishment', i.e. Farnborough? These cases could be obtained in a variety of sizes by any company looking for an enclosure for a (defence) project. They were stackable and had pressure relief valves for air transportation. You chose the size of case to suit your project and then you could order blank front panels and a variety of brackets and other internal hardware. The various component parts were supplied ready finish painted. I don't remember whether they were made by a single company or whether they were made by several companies to the RAE design. All the above is from my rather tired memory! I'll be happy to be corrected by anyone whose memory is in better condition or who still has appropriate documentation!!

Vacuum escapes easily. Sometimes you have to ..refill it. 😁

@simontay4851

10 ай бұрын

Haha! You're not wrong - kind of.

I had totally forgotten how it is to be in a 400hz environment, I remember how I always realized how quiet it got when turning things off.

When I worked in the UK Aircaft industry in the 1980's, one task we had was calibrating test equipment for the Tornado. We had a 240V AC/ 50Hz to to 115V 400Hz motor generator set installed, so we could power up the test kit in our lab. Can't remember how the 3 phase was configured though.

I LOVE watching your videos while repairing vintage HP gear!

Just for fun, removing the metal foil can from these germanium transistors lets you use them as crude photo transistors. This trick also works with the OC70 OC71 etc, if you scrape off the black paint on the body to let light into the glass package.

@kiltrash1

10 ай бұрын

Only the very earliest germanium transistors. Later ones were filled with opaque gunge to prevent unintended photo transistor effects.

@martinhow121

10 ай бұрын

@@kiltrash1 in the late 60's 0C71s could still be used as photo transistors. We had a demo rig used at school open days that used 12v vehicle bulb biased on with 11v and an audio amp adding modulation signal in parallel as a transmitter and a simple audio pre amp with a scraped oc71 as detector pre amp driving a little audio amp from optical interference from fluorescent tubes in the lab.

@TerryClarkAccordioncrazy

10 ай бұрын

I tried that and it never worked, the case was filled with some gloop that was probably poisonous because everything back then was a cadmium beryllium mercury lead asbestos benzene amalgam.

What a complex beastie!

@KitsuneAlex

10 ай бұрын

I am a electronics and software person, this is wild to me xD The machanisms in this thing are stunning.

That's a very special piece of kit and as always I have a lot of respect for your troubleshooting skills and knowledge. It's a great pleasure watching your videos Marc!

Smiths made the gauges and heater on my MG Midget.

@victormuckleston

10 ай бұрын

gauges on many british cars and clocks, they are now smiths metals , my daughter and ex work for them.

@tomschmidt381

10 ай бұрын

Yup, same with my MGB. Plus I bought a few more to add more gauges to the car.

@antronargaiv3283

10 ай бұрын

I once repaired a tachometer on a friend's MG Midget, txwas in the mid 1970s. The tach, when disassembled, had a proprietary TI (Texas Instruments) integrated circuit. I called the local TI sales office (my company did a lot of business with them) and they rummaged through someone's desk and sent me one, which I swapped for the defective one and got his tach working again. Which was a good thing, as the price he was quoted by the US deler for MG was astronomical.

I don't think I have ever seen a transistor big enough to see with the naked eye before!

@KitsuneAlex

10 ай бұрын

xD If you ever looked at a mid-2000 era circuit board before, you'll have seen one for sure :D Look up 2N2222, that's a classic example.

@kaitlyn__L

10 ай бұрын

@@KitsuneAlexthis prompted me to look up the die for 2N2222 and it’s interesting how there’s a bunch of different topologies. Which almost seem done for the sake of it, making me wonder if each shape was a particular company’s version or something. Though that’s still quite a bit smaller than the comparatively giant blob in this video!

@KitsuneAlex

10 ай бұрын

@@kaitlyn__L True for sure, i was just trying to find a very general reference for a transistor one can see with the naked eye as OP was referring x3 The die is different, but the package of a 2N2222 is generally TO-92, which is a very good example for such transistors.

@michaelcalvin42

10 ай бұрын

@@KitsuneAlex I assumed OP was referring to the die, not the package, as even modern SMT transistor packages are definitely large enough to see with the naked eye.

@KallePihlajasaari

10 ай бұрын

@@michaelcalvin42 TO-3 cans have nice dies inside. Carefull use of a hacksaw or Dremmel cutoff wheel will reveal the goods.

The contrast between the device under test and the scope is huge in this video... We've come a long way in 60 years.

Had one! beautifully made too.

British mil spec is top notch. My avo CT-160 tube tester is spot on whereas my us one is a bit off

That circuit diagram style was still being used by Wireless World in the late seventies and early eighties... I'd have laid good odds on those transistors being OC71 or OC72 :) I used to extract them from surplus ICL logic block packages when I was still at school in the early seventies.

Always happy to see a new video of you. can you do more Computer videos? I really love the old mainframe, xerox and HP 85 stuff

@CuriousMarc

10 ай бұрын

Yes, there are a whole bunch of mainframe and mini computers in the pipeline. But for now we are taking a detour into mechanical analog stuff, which are computers in their own right too!

@DangerousPictures

10 ай бұрын

@@CuriousMarc true, analog and mechanical Computers Sometimes feel Like black Magic wizardry to me tho

@benjaminhanke79

10 ай бұрын

​@@CuriousMarcI hope you and your friends get your hands on an fluidic logic device some day, a pneumatic computer without moving parts. That's something I learnt it exists but I've never seen one.

There are so many soviet diffused germanium transistors with production date in the late 80s on e-bay that making a DIY one will be purely for fun than out of a pratical need. Judging the looks of the P.S. filtering capacitor and comparing it with ancient soviet solid electrolite, niobium and tantalum capacitors it looks much the same, so it might appear to be more longlasting than a new modern capacitor.

@SeanBZA

10 ай бұрын

Yes Tantalum capacitor, I changed many of those which had failed, mostly due to either reverse voltage, or because of seal failure.

Super cool video :3 Mechanical stuff was always stunning to me as an electronics and software person, and this is no exception!

Amazing skills in electric and mechanic!

Cadmium plating corrosion. Lovely stuff.

Will be reeeeallly cool to see how to make those transistors

I can tell those are later Mullard transistors, because the earlier ones had a translucent silicone grease. This meant the black paint could be scraped off to make an ordinary 0C71 into an 0CP71 phototransistor. Because paint might come off and the light would then affect operation of a normal transistor, they changed over to two layers of grease. A Blue layer right over the junctions and a white layer on the outside. I remember having to buy a spare germanium transistor for my heathkit Electronics lab; in the UK an AF117 cost me the equivalent of $1.05 in 1965, which is about $10, nowadays.

Anyone else get the impression that when they says “oh no, I need to find X part” they are secretly happy?

Try looking up a TT- 205 pitot static tester. More automated perhaps but heck, how many ways do you need to move air and vacuum around. I used them onn F-4 Phantom II fighters when I was in.

@CuriousMarc

10 ай бұрын

Oooh indeed, these are nice, TTU-205. But $5,000 for a non working eBay unit!

@paulhancock7670

10 ай бұрын

Used them and others for CADC testing on Phantom FGR 2 in RAF (1970's & '80's)

Life is better @ 400 c.p.s.! Thanks for sharing your knowledge with us. Minions are cool too!

Aircraft Toaster?😮

Marc, wonderful video as always. I am always amazed at your trouble shooting abilities. It seems no matter what you work on you always find a way to at least understand what the problems are. And then there is all that wonderful test equipment. It all is simply amazing to me. Thank you for sharing your adventures.

@CuriousMarc

10 ай бұрын

Thanks for the kind words of encouragement!

I never saw anything that fun when I worked for Lucas in Witney (Aerodrome) that had bought the local piece of Smiths Industries.

Rating is 115V between 2 phases and not phase to neutral?

Fascinating. In the mid 70's I did a kind of digital version used inflight testing a DeHavilland Dash-7; The flight data was recorded on a 1/2 inch magnetic tape. I wrote a program on a Varian minicomputer to read the tape when the plane landed and do all the air data calculations so they could check if the data was reasonable to be used for further analysis.

Nice to see some UK stuff made it over there. Smiths of course made alot of avionics. Is the 3-phase inlet a Plessey connector? They were big in mil (UK) spec connectors.

@CuriousMarc

10 ай бұрын

Yes, that’s it, a Plessey connector! Thanks, I didn’t know what it was, now I can try to find one!

My ears popped just from watching that! XD

Cool stuff.

Awesome!

Good old Analog wizardry long before the computerized pitot tube sensor testers started to show up. And if the motor is jammed in certain spots, it would skip before reversing or anything weird it decide to do due to magnetic detents on the rotor if it's of a synchronous permanent magnet AC motor. And leaks somewhere would do it too, apparently (long before the advent of softwares that would warn you of problems, with some problems automatically corrected beforehand).

I wonder if silicon transistors would work if you adjust the bias resistors.

@SeanBZA

10 ай бұрын

In that circuit yes, they are biased into almost class AB operation, though your distortion will be a bit higher, plus a small dead band at low input levels.

What pressure does the capsule have to withstand, because there are tough flexible sealers. Plus if it's always vacuum, sealer on the outside will seal it, ie, ATM will keep it in place.

Amazing electromechanical analogue computer. Sad to see the vacuum capsule succumb to corrosion though.

I make Air Data Computers. I've seen machines of this vintage. I've used an old Penny-Giles

@joshkarpoff3341

6 ай бұрын

I work in a shop that serves professional audio for Broadway shows and the motorized linear potentiometers/ faders made by Penny & Giles have always been coveted by the audio engineers live mixing the shows.They have a much smoother feel over many months of use than the much cheaper equivalent from Alps.

20:51 nice juno

The insulators that were usually put around the legs of these OCs transistors will corrode them in almost all cases. It's a chemical reaction between the insulator and the pin of the components. In some old TVs it will happen with resistors

@CuriousMarc

10 ай бұрын

Interesting! I did not know.

@theelmonk

10 ай бұрын

Brings to mind the corrosive foam on HP logic analyser plug-ins

@CuriousMarc

10 ай бұрын

@@theelmonk Good point. I have had that problem too!

17:36 that would be a really cool experiment to show on your channel if you ever get a chance to :)

Likely irrelevant, but mentioning it still for the off chance it might be useful. I think I recognize the connectors used for the amplifier boards and the power supply as an Airborn series W (possibly WTA). Though if it is, it probably has the exact part number marked on anyway.

@CuriousMarc

10 ай бұрын

Looks like you are right on! Thanks for the tip!

Knowing you, you will be able to fix those bellows, I hope so anyway

@EricLikness

10 ай бұрын

I hope so too. 🤞Vacuum Bellows, you WILL meet your match. No stone un-turned, no resource un-exploited. This is curiousMarc.

Neat neat neat!

23:35 What's with the maple syrup? 😜

@CuriousMarc

10 ай бұрын

Water bottle for the soldering iron sponge! Syrup was pretty good too.

Are you still on half of the supply voltage ? To me the strange sound looked as if the gears and axes were worn out, and so came in an vibration which has its feedback to the power supply voltage.

Steampunk Heaven..

Smiths made quality technology

I will try again, as my last (admittedly jokey) comment didn't make it through. If you removed that bellow and sprayed it with a thin layer of a "liquid rubber" product, it may actually be a decent fix. I'm thinking something like flex seal which normally I would scoff at, but this might be a good use-case.

It´s typical for the 60ies designs to copy tube circuits with transistors - at least in case of radios. Newer radios had fewer transformers. I am not sure if it was the high cost of transistors back then or just the learning curve. Probably the letter. I don´t think they saved money on military devices 😀

I love it good 👍

Cool tester! Good thing you didn't smoke it by putting 115VAC L-N instead of 115VAC L-L! So L-L would be 1.73 times higher, or about 199VAC. But, lessons learned as always. 115V 3 phase is line to line, not line to neutral. Great video, as always!! Thanks!

@inothome

10 ай бұрын

Saw your comment further down about 115/200V in avionics. New to me, I deal with HV transmission and distribution, where when talking 3 phase it's always L-L. But I still don't understand why they would call out the lower voltage and not call it 200V 400cps? No biggie...

I think your planning to build a steampunk flying saucer.

Ha! The multi-stage, transformer-coupled push pull AC amplifier... Nice. Note the third stage, almost surely a bug in the diagram - ungrounded collector. Apart from the bug, the schematic is a thing of beauty in its own right, just look at these curvy lines... I wonder how that thing would sound as a guitar amp. Sooooooooo much gain. Time to put it in a Hammond box and name it "Smithstortion" ;) I looooooooove the combination of electronics and mechanics here. Most of the time I'm used to seeing you tinker with electronics, but this system is different and definitely interesting. BTW... it looks more dieselpunk than steampunk. 1920s stuff would be steampunkish though - with wood, brass, sometimes leather too.

@CuriousMarc

10 ай бұрын

Yes, it's missing a wire in the schematics. But it's easily corrected for by a little bit of imagination.

I have some military grade OC72 if you ever need more I can ship them from France.

I used a OA71’s in a breadboarded circuit mounted on paxalin back in the day…the transistors were painted black and if exposed to light became light dependant ? Transistors…?

@pe1dnn

10 ай бұрын

Must have been OC71 because OAxx are diodes like OA95...

Some dufus left it out in the rain. Those counters suck moisture and seize instantly. I never figured out if it's the grease or something else, like mayhaps leaching metal.

@CuriousMarc

10 ай бұрын

This one took a lot of water. There is a watermark at the bottom inside the case, maybe 1 inch or more. You can even see it in the video.

@aserta

10 ай бұрын

@@CuriousMarc Yup. I saw on second watch. I always watch these twice, lots of stuff to learn. Great video!

I used to pass Smiths Industries on my school swimming trips. Now I know what sort of thing they were building in there! (I have no idea if they had multiple sites, but this was the one in Ashchurch/Tewksbury). There was a Moog warehouse/factory? just down the road too.

@theelmonk

10 ай бұрын

That's the hydraulics Moog (moog valves) not the synthesizer one

I'm sure you've answered before, but what oil do you use in that super long oiler? Just a sewing machine oil? Or something more special?

@CuriousMarc

10 ай бұрын

It’s Nye 140B oil. Very special, but worth every penny.

@ElectraFlarefire

10 ай бұрын

@@CuriousMarc Thank you! I shall hunt down a bottle. (It also comes with the super long oiler too!)

I kept reading the title as 'Pilot Static....' in the thumbnails, that was until I watched the video.

You guys should use a little crc 5.56 or wd40 on the srews

British avionics equipment of this vintage uses some of the most annoying screws ever invented, they are often threadlocked and have slots in them that are both incredibly narrow and of very shallow depth. I've only other things I've seen such idiotic narrow slotted screws fitted to are traditional shotguns. You only have one or two chances to get the screw to move before the slot becomes chewed up. Ideally you want to find gunsmiths screwdrivers to have any hope of getting the blade to fit at all, or to make your own hollow ground screwdrivers from O-1 tool steel. Giving the screw a light tap sometimes helps in removing it, depending on whether you can get away with that because of fragility considerations.

kool :)

115V is the phase to phase voltage, not the phase to neutral.

@CuriousMarc

10 ай бұрын

You'd think so, but in avionics 400 Hz AC, also known as 115/200 400 Hz, it's 115V to neutral, and 200V phase to phase. It has been standardized like this for over 75 years. Unless the British do not follow the rest of the world, which wouldn't be the first time...

@itsverygreen532

10 ай бұрын

@@CuriousMarc That's a good point. I have some friends who worked for Rolls Royce back in the day, I shall ask and report back! Normally in the UK if we have 240V single phase (neutral to phase) we call that 415V 3 phase when we have 3 phases in the UK, we always use the phase to phase voltage to describe the supply voltage of three phase systems ... I'll ask the "old hands" and see what they have to say.

@CuriousMarc

10 ай бұрын

Aha. After much searching, I have finally located one avionics inverter that claims to do both, 115 phase to neutral but also 115 phase to phase: kgselectronics.com/resources/sales-information/91-static-inverters-400-hz-tso-d.html . Although when you read the spec it’s not in there. But maybe the mode really exists. 115 phase to phase is the only sensible explanation I can come up with too.

@CuriousMarc

10 ай бұрын

More aha. Michel (from the channel “le labo de Michel”) figured it out. It’s indeed 3 phase 115/200, **but** it’s not using the 3 phases. It’s using 2 phases on A and C and B is neutral! These silly British…

I´m wondering if an IR detector would not be a practical and effective diagnostic tool to be added to your bag of tricks and techniques....

10:02 The voice over and added graphics say capsule A is static and capsule B is pitot. Shouldn't it be the other way around? In the top right of the original diagram it says A is pitot and B is static.

Good

Um, I don't think your supposed to dive an aircraft at Mach 3... 🙂

In ex Soviet country there is an excellent system named УВПД. I have one, it is much more accurate than this one. It has five(!) such meters

It's a great shame British Aviation industry died from the war up untill the 70s the uk made great aircraft.

@melanierhianna

10 ай бұрын

The UK Aviation industry still exists. Its just part of a bigger whole. The Tornado and Typhoon were partly built by BAE systems which also builds a lot of other stuff.

fibre optic giroscope internal plis curosmsrk

Hi!

Smiths made parts for cars and motorcycles too speed and oil gauges etc.

Ah yes the air data computer EEVblog cut open with an angle grinder and probably threw it in the bin after. I apologise on behalf of all Australians for his behaviour.

The only moving part a electronic product should have is a RESET button.

Dieselpunk. Not steampunk.

First - because apparently that is still a thing.

@CuriousMarc

10 ай бұрын

It is a thing. Her Majesty awards you a free vintage and very leaky vacuum capsule for your firstness.

@Bobbias

10 ай бұрын

​@@CuriousMarcI'd say something to the effect of "but it's His Majesty now" but we all know there's nothing majestic about him :)

@bensmith3304

10 ай бұрын

@@CuriousMarc Woohoo!🎉

On old mod base's they leave this kind of stuff to rust . Old mod base's are never brought back to nature theres so many abandoned base's that could be converted into parks or homes . The mod keep the land and do nothing with it all over the uk this is a problem.

Here we are in 2023 and the current count is zero comments but there are more than ten comments below this as I write. When current technology does not function as "telegraphed" my reaction is "it's a generational thing" which is itself a reaction of a "digital native" to my using older digital tech as a backup to a current "smart-phone" app. Nowadays its : Garbage in, Garbage wrangled by a faulty algo Out with some bleeper telling you it's OK and you are the problem.