EEVblog #920 - World's First Transistor Watch! - Page 1
Forum section: electronics / general

author: EEVblog
author_rank: Unknown
timestamp: September 07, 2016, 10:45:06 pm
content: The Bulova Accutron Spaceview 214, the world's first transistorisedwatch!Space age technology from the 1960's, the world's most accurate watch at the time using a 360Hz tuning fork mechanism. Used by NASA on many space missions including Apollo 11.See it operate at 1000fps!All the info:http://members.iinet.net.au/~fotoplot/acc.htm

author: MK14
author_rank: Super Contributor
timestamp: September 07, 2016, 11:15:01 pm
content: Thanks I enjoyed that. I'm amazed that it had 8,100 turns in those tiny coil, and that it had ONLY a single transistor, as the non-passive components. Not even a single IC there.2 seconds per day accuracy, is pretty remarkable for a non-quartz time piece.They were very impressive at the time they were popular (ignore the pun). But since they have been available until now, that DOES not mean you can guess my age. I was somewhat fascinated by them, and I agree, the sound was really something as well. The smoothness of the second hand movement was fun to watch.Thanks for doing the video in such a comprehensive way. Seeing the back of it again (I'm NOT 100% sure it was that exact make etc, but it seems that it was), has brought back memories. Also taking the effort to record the sound, reasonably well, was a nice touch.Seeing the 1,000 frame per second, was interesting seeing the tuning fork oscillate like that.The purely mechanical watches of that time era, were pretty ropey by today's standards. What with forgetting to wind them (although some had weights which auto wound the springs), very poor time accuracy (in later ones, forgetting to advance the date at the start of the month, as this was not automatic) and an amazing lack of reliability. Some people would have like half a dozen (broken, but too expensive to bin) mechanical watches in their bedside cabinet, because they would tend to break every 6 months or so.I think they were VERY expensive. I'm guessing, but maybe £500/$750 or maybe more (or less), in today's money. The battery life seems impressive as well, although I'm not clear exactly how long it lasts.

author: EEVblog
author_rank: Unknown
timestamp: September 07, 2016, 11:16:31 pm
content: Quote from: MK14 on September 07, 2016, 11:15:01 pmYeah, US$1000 in today's money I believe.

author: jnissen
author_rank: Regular Contributor
timestamp: September 07, 2016, 11:25:13 pm
content: This is really cool! I had no idea that tuning forks were ever used in wristwatches. Fascinating stuff to consider this was developed in the early 60's. I really liked the slow motion showing the actual mechanical movement of the tuning fork. Good job.

author: MK14
author_rank: Super Contributor
timestamp: September 07, 2016, 11:26:30 pm
content: Quote from: EEVblog on September 07, 2016, 11:16:31 pmI suppose it is sort of equivalent to having the latest Iphone 7 or similar, so $1,000 is not so ridiculous. Many people (including me), get rather lost without an accurate time piece. By the sound of it, it was like the watches that were to come out some fifteen to twenty years later (quartz=accuracy + LCD=long battery life, since early LED ones had a potentially poor battery life and having to press the button to turn the Leds on for a second or so, was a pain at the time, I would think).

author: EEVblog
author_rank: Unknown
timestamp: September 07, 2016, 11:31:12 pm
content: Quote from: MK14 on September 07, 2016, 11:26:30 pmYes, it owned the market for something like 10 years, nothing else could touch it.

author: MK14
author_rank: Super Contributor
timestamp: September 07, 2016, 11:46:28 pm
content: Quote from: EEVblog on September 07, 2016, 11:31:12 pm10 years is a very good run, and they would still make smashingly nice watches, even today.It is a clever combination of electronics and mechanical engineering.Because motors tend to use a hundred or more milli amps, if not amps, solenoids tend to use amps, and relays are often around 150 ma's, but can be lower or higher. How they get it to use such a tiny amount of power is also impressive.Presumably it uses about 10 micro amps (guessing 100ma/hour battery capacity and 1 year life, battery life info via an internet search).So about a 10,000th of what a (100ma) relay coil would use. I guess the 8,100 turns in the coil helps, and it only needs a relatively tiny movement to keep going (resonance), so the current scales down. Still amazing.Also the current may only be needed for tiny fractions of a second, so it may be a couple hundred micro amps, but only for 5% of the time, or something like that. So 10 micro amps, is the AVERAGE.EDIT: tl;drIt would be interesting to connect a scope up to it, and see the current that it uses, and its waveform, over time. Is it discrete pulses of consumption or a more continuous affair ?Any capacitors across the supply would make it a lot harder to measure (a quick look again at the circuit diagram in the video, seems to show that the capacitor is NOT decoupling across the battery, so it should be ok). I guess these watches are so valuable, tiny and delicate, it is difficult to sort out.Your video shows how difficult it is to open them as well, ideally needing a special tool and great care and training (on how to open those watches).

author: nctnico
author_rank: Super Contributor
timestamp: September 08, 2016, 12:25:43 am
content: I wouldn't be surprised that movement of the tuning fork circulates some of the energy around so it may use even less energy than you'd expect when just driving a solenoid.

author: MK14
author_rank: Super Contributor
timestamp: September 08, 2016, 01:02:58 am
content: Quote from: nctnico on September 08, 2016, 12:25:43 amWell one of the pages, found by following Dave's original link in the OP post, has a fair amount of technical details, explaining how it works.http://members.iinet.net.au/~fotoplot/acctech.htmIt does seem to say that it is "off" a fair amount of the time (using little power), but through the use of the feedback coil(s), the transistor turns on and regulates the thing, as it oscillates. Amazing for just a single transistor, and very clever because transistors were incredibly expensive, in the early days of those watches being produced. So if it had, had twenty transistors, it would have probably been considerably more expensive, and maybe too big to easily fit in a watch.It also would probably have used too much current. they could of just about put more transistors into an IC for it. But in the early 1960's IC's were in their very early days and would have been prohibitively expensive (I think).The linked to article does say it was a significant/major job to develop it, like it ended up.Extract:Quote

author: Tim T
author_rank: Contributor
timestamp: September 08, 2016, 02:36:01 am
content: Nice blog.Bulova date codes are1950's: L1960's: M1970's: NSo Dave's watch M9 = 1969.This is one example where it would be better not to take it apart. The case and movement could be easily damaged if handled by a novice without the correct tools and training. No offense intended... watch repair is a hobby of mine and while comfortable disassembling/reassembling a typical 17 jewel mechanical movement I will not touch an Accutron.tim

author: rollatorwieltje
author_rank: Unknown
timestamp: September 08, 2016, 05:49:07 am
content: The index wheel on this thing is less than 3mm in diameter and has 320 teeth. I wonder how they mass produced that. Even with a microscope the teeth are barely visible.

author: TheSteve
author_rank: Unknown
timestamp: September 08, 2016, 05:56:47 am
content: I want one! It would look great next to my 1991 Motorola Pager Watch.

author: Fungus
author_rank: Super Contributor
timestamp: September 08, 2016, 06:36:54 am
content: How long does the battery last?

author: Fungus
author_rank: Super Contributor
timestamp: September 08, 2016, 06:55:14 am
content: Quote from: MK14 on September 07, 2016, 11:46:28 pmI dunno about "training" but yeah, it's a special tool to unscrew the back. You can get one on eBay for <$5.eg.http://www.ebay.com/itm/232019738190

author: G7PSK
author_rank: Super Contributor
timestamp: September 08, 2016, 07:52:12 am
content: In the late 60's early 70's I was an apprentice watchmaker. I can remember one of those being brought in for repair, as a lowly minion I was not even allowed to touch it that and the service was reserved for the boss. Around 1967 Seiko introduced the quartz watch which as I remember it was advertised as being accurate to 3 seconds in a million years, I always wondered who would ever be able to claim on that.The second hand on the Bulova watch dose move in steps it has to due to the way the mechanism works, it is just so small and so fast a step that it looks smooth to the human eye, the first quartz watches were the same but soon got reduced to one second movements due to power requirements. Some of the very early watches had a rechargeable battery in the back and were recharged with what looked like a converted torch, the front lens of the torch was removed and a clip like device was screwed into the bulb holder. The clip thing had a single resistor inside to limit the charge current and the watch batteries were around 30mm dia and 2 to 3 mm thick and I think some type of Ni-cad.

author: MK14
author_rank: Super Contributor
timestamp: September 08, 2016, 08:06:56 am
content: Quote from: Fungus on September 08, 2016, 06:55:14 amAs Dave explains in the video, and from reading sources about this watch myself, in response to the video. They seem to explain that opening this watch (even to ONLY change the battery), needs *training*, so that you can avoid damaging the delicate and very rare/expensive collectors watches.Apparently opening the back, is only the first part of the problem in repairing the watch and/or changing the battery.The "training" can probably be done by reading up on how to service these watches (including simply changing the batteries), and maybe watching any applicable youtube videos, if available. Especially if you are already into electronic item repair.

author: G7PSK
author_rank: Super Contributor
timestamp: September 08, 2016, 09:20:53 am
content: You also need very fine mechanical skills to repair these watches, they still have gear wheels and an escapement device the only difference between these and clockwork watches is the driving force.

author: Fungus
author_rank: Super Contributor
timestamp: September 08, 2016, 09:48:32 am
content: Quote from: MK14 on September 08, 2016, 08:06:56 amYeah, I wasn't talking about repairing it or taking the innards out. The claim was that simply taking the back off is difficult. It isn't.

author: MK14
author_rank: Super Contributor
timestamp: September 08, 2016, 09:56:29 am
content: Quote from: Fungus on September 08, 2016, 09:48:32 amBut if you need a special tool, which most people don't have. Then I'd consider that not so easy to open, then.If Dave with all his impressive electronic tools, equipment and skills, can't open it, without purchasing a special tool. Then I'd consider it far from easy, even to open the back up.It might be all too easy to somewhat badly scratch the watch (especially the back), if you don't even know how to take the back off properly. So if it is worth a large amount of money (rare collectors watch) and still in relatively scratch free condition. You could do hundreds of dollars worth of damage, just by clumsily taking the back off.I DON'T know that for certain, but that is the impression that I got from watching Dave's description of the situation and my own experiences, of trying to open difficult watch backs.

author: Fungus
author_rank: Super Contributor
timestamp: September 08, 2016, 10:15:24 am
content: Quote from: MK14 on September 08, 2016, 09:56:29 amIt's not like it's welded shut though, or needs a special waterproof gunk to close it back up again or something like that.The astro-computer teardown linked to at the end of the video.THATwas "difficult to open".Needs a special $5 spanner? Not in the "difficult" category. Not really.

author: rollatorwieltje
author_rank: Unknown
timestamp: September 08, 2016, 10:28:59 am
content: Even with that tool it's a pain to do it. When it hasn't been opened for a long time quite often the back case will be extremely stuck. It's even worse on this watch as it has a separate battery slot. Theproper toolhas the exact dimensions so it's less likely to slip. It's best to replace the gasket as well when you open it.There's also nothing interesting to see, you still can't take the movement out and the rear doesn't show much anyway. You'll have to disassemble the movement to look at the gear train. I highly recommend you don't do that without experience.

author: MK14
author_rank: Super Contributor
timestamp: September 08, 2016, 10:34:49 am
content: Quote from: Fungus on September 08, 2016, 10:15:24 amWe are not really disagreeing here (just having different perceptions of how difficult something is). It is somewhat arbitrary, what people consider to be difficult and easy. For ME, I would definitely consider that difficult and best left alone. I don't like having to go out and buy special tools for things, when I have a fairly comprehensive set of screwdrivers etc, already available to hand.I somewhat recently tried replacing the battery, on my fairly cheap, "normal" digital watch. It has ridiculously tiny screws, one of which I managed to drop/lose permanently, and had great difficulty opening it.It then had this horrible metal flimsy clamp thing, which I couldn't easily see how to get it to open, and out of frustration, managed to bend it (and/or snap plastic bits of it or something) and make it fall out (in a way it was probably NOT suppose to).As a result the alarm sounds/beeper is almost 100% bust and I ended up leaving the old battery in it. When it eventually fully runs out (maybe a 10 year lithium battery), I will probably scrap the watch and use another one or buy another one. I have had the watch a long time, and I think it is already on the (if I remember correctly) second or third battery (previous attempts were successful at changing the battery I think), and it is partly worn, so it is not a problem, scraping it.Quote from: G7PSK on September 08, 2016, 09:20:53 amThis I think is the main reason why it is recommended not to open one, unless you are ready for them.

author: Fungus
author_rank: Super Contributor
timestamp: September 08, 2016, 11:13:51 am
content: Quote from: MK14 on September 08, 2016, 10:34:49 amBut ... youalreadywent out and bought some special-purpose screwdrivers?

author: amyk
author_rank: Super Contributor
timestamp: September 08, 2016, 11:16:59 am
content: Obligatory service manual link:http://www.timetrafficker.com/about/watch-care/pdf/accutron-214-service-manual.pdfQuote from: G7PSK on September 08, 2016, 09:20:53 amUnlike typical mechanical watches which arerelativelyrobust, the index wheel in these is extremely fragile and easily damaged (and also quite expensive.) The teeth are approximately 10um high.

author: MK14
author_rank: Super Contributor
timestamp: September 08, 2016, 11:24:22 am
content: Quote from: Fungus on September 08, 2016, 11:13:51 amCompared to many households, I agree. We typically have many things most house holds don't have, such as oscilloscopes and MCU test boards, etc etc.I suppose if you had an old version of that tuning fork watch, did not realize how valuable they were, and it was already broken and/or somewhat badly scratched. You could probably buy that ebay tool, and open it up.But as others have said/implied, that is probably not a good idea. It is better to either let someone with the skills and experience of dealing with those watches, handle it. Or train yourself up, using available resources.

author: Fungus
author_rank: Super Contributor
timestamp: September 08, 2016, 12:44:51 pm
content: Quote from: MK14 on September 08, 2016, 11:24:22 amI never said it was agood idea, just that it isn't particularly difficult to open it (as previously claimed by some).

author: Tim T
author_rank: Contributor
timestamp: September 08, 2016, 01:42:43 pm
content: Yep, not difficult at all...

author: kalleboo
author_rank: Regular Contributor
timestamp: September 08, 2016, 02:44:07 pm
content: Opening things is never difficult, it's putting them together again where it gets tricky

author: MK14
author_rank: Super Contributor
timestamp: September 08, 2016, 02:52:22 pm
content: Quote from: kalleboo on September 08, 2016, 02:44:07 pmI use to sometimes open up (to repair them), the older type of calculators. With some of them, when you do that (probably after taking the PCB screws out as well), almost all the keys can fall out, all over the place, unexpectedly.You then have to spend ages, finding them (on the floor), and finding out what button goes where.

author: G7PSK
author_rank: Super Contributor
timestamp: September 08, 2016, 04:08:06 pm
content: The"special tool" is nothing other than a pin spanner with square pins the back is threaded all you need to be careful about is cross threading on re assembly.

author: Tim T
author_rank: Contributor
timestamp: September 08, 2016, 05:34:40 pm
content: You need to be careful about...- selecting the correct tool and its use for removing the bracelet without scratching either it or the case.- selecting the correct case clamp/holder for securing the case without scratching it or the crystal, or bending the lugs as a consequence of applying torque while removing the case back.- selecting the correct tool for removing the particular case back. My understanding is a competent watchmaker will have tools covering many possible options. Some are quite simple - essentially a sticky rubber ball - others are quite elaborate and rigidly hold both the case and wrench in fixed planes to prevent slipping and gouging (e.g Horotec 07.369 for about $2000). Snap back cases are an entirely different world.- holding the pin type spanner perfectly parallel with the case back while applying torque, not as easy as it sounds. The earlier posted photos are typical examples of when someone failed - actually the damage on one was originally much worse and the picture was taken after some lathe work. I use the American made LG Master wrench on my beater watches but you need to hold it in such a way that pressure can be applied downward evenly across all contact points, and in the intended direction of rotation.- agree about risk of cross threading but this is relatively easy to avoid with a bit of care since you should screw the back down by hand and only use the wrench for the final 1/4 or so turn.The point of course is to leave no evidence, even under magnification, that you ever opened the back of the watch.I doubt many on this site would use a free/$2 DMM to test mains voltage, so why use a cheap Jaxa knock off wrench on a valuable watch?regards,tim

author: tatus1969
author_rank: Super Contributor
timestamp: September 09, 2016, 10:40:53 am
content: very impressive, enjoyed that video. How would these have been tuned/adjusted? Can't see anything. Or would they just rely on manufacturing precision of the tuning forks? Did they drill holes to adjust the masses? And does athmospheric pressure have negligible detuning effect?

author: rollatorwieltje
author_rank: Unknown
timestamp: September 09, 2016, 11:17:33 am
content: Quote from: tatus1969 on September 09, 2016, 10:40:53 amAfaik there's no adjustment for the 214 movement, the tuning fork was factory calibrated by taking notches out out the base. The ESA 9162 movement (used by Omega) was adjustable, it used a different fork design, which was also less sensitive to orientation.

author: albert22
author_rank: Regular Contributor
timestamp: September 09, 2016, 01:58:04 pm
content: You can find the regulation procedure in the service manual for the model 214 (page 10). Which was linked by amyk. BTW thanks amyk.Although the pictures are not very clear to realize what this regulation does.According to the manual the regulation can be affected by air variations and the vicinity of the needles to the coils.

author: Noize
author_rank: Regular Contributor
timestamp: September 09, 2016, 07:59:27 pm
content: This guy made mechanical watches by hand that were more accurate than quartz.http://www.danielslondon.com/

author: electr_peter
author_rank: Unknown
timestamp: September 09, 2016, 09:20:07 pm
content: I would not try to open this watch because time setting knob (or crown) is on the backside, not on the side. You definitely do not want to mess that up!

author: richnormand
author_rank: Unknown
timestamp: September 11, 2016, 08:43:09 pm
content: I do not have a Spaceview but the regular model. Marking is M6 making it 1966 vintage. It wakes me up at night if I leave it on the wooden dresser in the room. If it is sideways at the right location the whole resonates like a guitar and you hear it across the room.When I got it a while back it had been damaged due to a leaky battery and it had been stored like that for a decade.Took me a long time to fix and get running properly but I don't remember it being particularly tricky to open. I did have Omega's dismantling and repair instructions on CD from a while ago to do the repair.I re-phased it (under binocular microscope) to use a regular 1.5V button batteries since the original mercury batteries are hard to get. Note that some watches cannot be made to run properly that way as you will end up at the end of adjustment or with double stepping on the index wheel. In that case, your other option is a voltage dropping diode. That would be easy to do nowadays with the availability of ridiculously small SMD diodes! I also machined (not visible from the outside) the inside battery hatch button to accommodate the cheap earring aids batteries of the time that were thicker than the original.To check its accuracy a simple phone pickup coil (black blob in photo) coupled to an Ithaco low noise preamp is fed to a frequency counter. No need of a microphone.I still wear it occasionally. A nice piece of history.

author: ian.rees
author_rank: Contributor
timestamp: November 12, 2016, 09:53:21 pm
content: Quote from: tatus1969 on September 09, 2016, 10:40:53 amThere are small adjustments on the back of the permanent magnets of the tuning fork for normal regulation. Also, I think the fingers that drive the index wheel can be manipulated to some extent.

author: ian.rees
author_rank: Contributor
timestamp: November 12, 2016, 09:56:06 pm
content: Quote from: Fungus on September 08, 2016, 06:36:54 amMine seems to last a year and a half, maybe a bit more, on a battery.

author: ian.rees
author_rank: Contributor
timestamp: November 12, 2016, 10:00:52 pm
content: Here are voltage waveforms at the two terminals of the "cell coil" - from memory, the yellow one is between D1 and D2 in Rob's schematic above and the blue is between F1 and the R+C.

author: Stebanoid
author_rank: Contributor
timestamp: February 07, 2017, 06:39:22 pm
content: Here is a slow motion video of the mechanismhttps://youtu.be/CPS7aNCAwAA

author: grumpydoc
author_rank: Super Contributor
timestamp: February 07, 2017, 06:54:45 pm
content: My father had one in the 1970'sI think he still wears it

author: mikerj
author_rank: Super Contributor
timestamp: February 08, 2017, 11:28:26 am
content: What happened at 2:43, did Dave power up one of his flux capacitors?