Dissecting A Vintage LED Clock - For Science!

[@bigclivedotcom]

I accidentally destroyed my first LED digital clock by damaging one of the wire bonds onto the LEDs while exploring it. The modern clocks use small surface mount chips in the same light-box system. That classic clock chip was super-popular. They usually get a timing reference from the mains frequency with a solder pad to select 50 or 60Hz. I wonder why the diode's chopped.

[@WilliamTresnon]

Super cool seeing you here. I'm a big fan of both you and Fran.

[@FranLab]

I assume the diodes were chopped to curb the rectified voltage.... perhaps they started using a slightly hotter transformer.

[@whitesapphire5865]

@@FranLab When you first mentioned the snipped diodes as a means to cut the operating voltage, I immediately thought "That's why the display is so dim". Maybe earlier versions suffered a lot of failed LEDs? So someone hit on the idea of a cheap and dirty trick to extend the life of the display, by under-running it?

[@christofhagedorn]

@@whitesapphire5865 I've seen in a different application, that a diode is used to tell the decoder if it is a 50 or 60 Hz supply.

[@ZenZaBill]

I have this same large format LED clock in a boxy industrial design enclosure. It blew the 12v transformer when my landlord miswired the apartment and put 230V in w/ a gasoline generator during a PG&E-imposed power outtage b/c of 'fire' danger. Interesting to see the exact same clock face and control functions in a thin packaging design. The boxy version I had was bought c. 1981.

[@mangamaster03]

Fran, I love the gentle way you tried to take this apart, but it did make me laugh when you popped it open with the screw driver. It reminded me of Big Clive's vice of knowledge.

[@hackmiester1337]

I was laughing my ass off. We have all been there.

[@jasons8479]

When I started working at Radio Shack in the early 90s right out of high school, I enjoyed experimenting with all their gadgets on display when it was slow between customers. I was like a kid working in a candy store with free samples! I remember discovering that effect of LED segments alternately disappearing on video camera due to their multiplexing rate differing from frame rate on the camera. Another effect I discovered was pointing a laser pointer's tiny dot at the unlit segments causes the entire segment to light up due to its diffuser spreading out the light just like it would from the LED coming from behind. Luckily I worked in a mall that was very slow and had lots of time to experiment with things and open them up and figure out who made some of their private label products. Many actually came from the makers of well-known brands like Sony, Uniden, Aiwa, Casio, Sangean, Eveready and Pioneer, and others were custom products designed specifically by or for RS. They once owned some factories of their own but had been transitioning away from those around the early 90s. They made their own coax cable, antennas computers and cassette tapes, for example, with factory photos even appearing in their catalogs in the late 70s and as late as the early 90s they mentioned owning and operating as many as 33 factories in 6 countries including the US.

[@kimpetersen2848]

Nice video ! I remember seeing what I belive to be this very model of clock in a Columbo episode from 1990 (Season 9, Episode 3, 19 minutes and 45 seconds).

[@ColinJonesPonder]

10:40 - when Fran does a Big Clive! 😂 Good to see you back in the lab!

[@fredknox2781]

Fran needs a vise of knowledge

[@mangamaster03]

@@fredknox2781 I just made the same comment a moment ago. Vice of Knowledge, meet the Screwdriver of Unreasonable Force.

[@tonymanzo3766]

I’m more a fan of fixing equipment rather than take apart to never work again. I know the stuff is not really worth much, but it’s working. Big Clive takes cheap things apart never to work again, shango and 12 volt videos all try to make non working stuff work, even to the point of why bother, but I get satisfaction when I see the unit working after all of that effort.

[@TheBluemanBenny]

LOL! I Still have that Spartus on my night table, and it still works. I bought it back in the late 80s. Thanks for all the hard work and great videos Fran!

[@sirthomasnolan]

Same, mine came from my parents house, I dropped it several years ago and broke the cover off. Still works just fine.

[@hippynurd]

haha, I got a scraptop to refurbish and it came with the bonus of a DVD of spirited away.

[@ericzimmerman7524]

From a manufacturing point of view, something like this sold in the early 90's would have been taking advantage of existing injection molds and "new old stock" sitting in storage. I would gather a company bought the lot and shipped it to China to produce it for a discount market. As you know, the 80's were a volatile time for electronics and the advancements on faster and cheaper components was extraordinary. I imagine there was tons of products left behind in the wake of keeping up with what is new and exciting, and this is a good example of someone trying to utilize this glut of outdated tech with a mix of old tech and new components.

[@SeanBZA]

Those were pretty much all Made In Honk Kong, with them likely still being made in China, for a company in Hong Kong instead, but with the whole assembly plant having moved over lock stock and garbage bin, though i would guess a good portion now come from cheaper labour markets, like Vietnam and Pakistan.

[@motten]

The prising off of the lens and then throwing down of the screwdriver really got me. 😂

[@johntaylor6992]

I relamped all my old LED clocks this weekend with modern 0603 and 0402 LEDs. Now they are super bright!

[@hanksmith3628]

I had one of those WAAAAY back when. Worked for about 30 years. I got it because was easy to read without my glasses.

[@Maxxarcade]

Interesting how the first digit appears to have room for more LED's. Probably so it could use a 24 hour format in some models? I also noticed that the screw had cut through the battery cable.

[@KOZMOuvBORG]

Unit on left has enough LEDs to display 1 and 2, one short of a 7 segment display

[@ElectronicTonic156]

I've taken apart quite a few bedside LED clocks over the years. The TMS3450 is a staple of 80's and 90's clocks and clock radios. It has a pin that can be set for 12-hour or 24-hour mode. Unfortunately, the LED board is not populated with the A, D, E, G segments for the left-most "2", so you couldn't use 24-hour mode anyway if the clock was still in one piece.

[@goodun2974]

I am curious as to how accurately the clock will maintain the time on the battery if it's unplugged from the wall. My wife and I have 1990's-era digital clocks in our bedrooms (one is a WestClox, and I forget the other brand) and they will *gain time* if the power goes out for any length of time. If the power goes out for an hour or two, my clock will have gained 15 minutes or so when the power returns.

[@SeanBZA]

Very poorly, the backup clock source is a 5Hz RC oscillator, deliberately set so as to run a little slow when on battery, as advancing the time to catch up is a lot easier, due to the simple set mechanism, that can only count up, instead of counting down. The RC clock there is used in the keyboard debounce as well, and being old NMOS processes the power consumption is not exactly stellar, though a fair chunk of the clock chips in use still are even older ancient process dinosaurs, using IIL logic instead, and having on the die a power regulator to provide the 1.1V they operate on, off of the typically 15V power rail. Some of those old chips (I have one of the old 1980's era ones, with it's 2W dissipation on the clock chip alone) in things like bedside radios would only last a few hours on battery, draining the PP3 battery down fast, and at 7V lighting up an even duller and faint low battery red LED, using a zener diode and transistor that normally, above 7V shunted the LED. Thus dim, because it used a 47k series resistor, and another for the zener diode as well.

[@eDoc2020]

@@SeanBZA I thought it was 900Hz, not that it makes any difference in terms of accuracy. This is not coincidentally also the frequency of the alarm buzz.

[@00Skyfox]

When we were kids my brother and I tore down numerous LED clocks we got at garage sales. If I remember right they were all single LED per segment clocks despite being from the early 80s or earlier. I still have one or two of the display boards in my circuit board parts bin, now 35+ years later. Even though they’re bare die LEDs getting tossed around in a junk bin, some of them still work!

[@drlegendre]

That particular Spartus design is my absolute favorite LED clock of the late 70s era. I currently own two of them, both were thrift store items and botn have run continuously since I bought them almost 30 years ago. I really like the styling - the control panel, the full-size Fresnel lens and the 2" LED 7-seg displays. And apparently they're reliable, too. If I have a gripe, it's the rather brief run time of the 9V power-fail backup battery.. the clock chip must have a fairly large current demand, as it will only keep time sans-AC for a few hours, it seems. Such a large battery should hold up for years, if it were a modern low-power CMOS design. For comparison, look how long a tiny little 2032 cell lasts in a PC motherboard.

[@JoshColletta]

Oh wow! I grew up on that Red Skelton VHS set! Hours and hours of laughs!

[@WalterKnox]

I have this same clock, used it for many years. It definitely is not as bright as it used to be, but it is still very visible, and I really like the old red ones like this much better than the overly bright green ones. The only thing about this one is that it makes an audible buzzing sound when not displaying all four digits.

[@PositionLight]

Oh wow, my grandfather had one of those exact same clocks and I used it until it eventually died. After a while I had to put a C-clamp on a specific place on the front to get some circuit to connect and get the clock to light up.

[@PositionLight]

This design of clock is much earlier as my grandfather died in 1992. Perhaps earlier models had different internals.

[@elektron2kim666]

I had a good one in the 70s and it was mainly a radio and I could mess my alarm up with a turn off timer for the radio channel I chose to fall asleep with. I was fascinated by the complicated constructs the light was coming from. It served for many years and I don't think it broke. It got replaced by something more precise.

[@Dingomush]

I liked the tear-down vid. Everything is a chance to learn something. Thank you, Fran.

[@jsl151850b]

13:39 Patch those broken diode leads to create a full wave rectifier. Brighter LEDs??

[@nickdiamond7595]

10:40 when it gets real. Love you Fran. This would be me from the start😁

[@goodun2974]

At 12:50 and onward, the display appears to be made with similar technology to the LED digital displays found in some stereo receivers of the late 80's and early 90's, which unfortunately dim irregularly over time, depending which stations were listened to the most. (Nakamichi receivers used small green segments, or sometimes red, in a smaller plastic sandwich). I did notice that one resistor located near to the display is evidently running pretty hot, or perhaps it is mostly being overheated by the diodes next to it.

[@MartysRandomStuff]

Had to wait until I got home and check but I have the same clock with slightly differently shaped buttons, same exact shape to the case, same name. Label on the bottom of mine has no instructions. Not sure when I bought it, late 80s or early 90s. It's been running continuously since I got it. Over the decades it's been moved between different rooms, the dim display is great for a dark home theater room.

[@rampart1234]

A most amusing video. Thank you.

[@CARLiCON]

I have a GPX clock from the same era, same size display & cabinet but also has an integrated AM/FM radio alarm, still works great

[@AI_Image_Master]

Holy F Batman. I have that exact clock. Been using in non stop since 1985 since I was in college. A girl in my dorm got it for me for my Birthday after I complained about the little travel clock I was using. Looking at it right now, and it is still bright. Can't say that I ever used the battery option also. Mine says Made in HK. Though you have a "newer one" I have one from the 80's. This is awesome.

[@thegreatmrp]

So very cool. I love the technology you show us, it fills in so many gaps that I've wondered on how things work since I was a kid in the 80s. So many things you've covered like the old clocks, and especially different historic displays that I didn't even know enough to actually look up in most cases if I even wanted to find out. I really appreciate the way you approach and present the information. Its pleasantly conversational, and you always have the best "stuff". Thank you!

[@lee4hmz]

If the number on the back of the panel is any indication, it's an older Liteon model. The datasheet is really easy to find, and the schematic on it even mentions the two dies per segment.

[@larryrivers1471]

OMG I had that exact type of clock for decades. I miss the thing so much.

[@catlady8324]

That clock goes for about $10 on the eBay as of 10/2022. Most sellers list it as from 1980-1989.

[@pauljs75]

Seems like it could be a predecessor to the current large display AcuRite clocks. A few generations removed and the buttons migrated to the back for a cleaner display-only look. (Model 13003?)

[@perwestermark8920]

That it looks less dim in camera - might that be a question of wavelength? I know I have issues seeing deep red while it gets easy either on a monitor or if I use a LED flashlight to shine on maybe a book or film tiyle printed in red on black. It was the low energy, long wavelength colors (red and IR) we got first for LED and blue and UV are the most recent ones (and the ones requiring the highest voltages since shorter wavelengths involves higher energy levels).

[@JimHendrickson]

Cool teardown. I was looking for a large-ish 7-segment clock display for a project and haven't been able to find much that's reasonably priced, and I have a digital clock of similar vintage (early 1990s) that I haven't used in years, with a large display like this one. I thought of pulling it apart, thinking it would be a self-contained module (like the small ones you can get at Adafruit). Seeing this I now realize that I'd probably just end up with a busted clock and a display that wouldn't be as useful as I thought anyway. I guess I'll keep looking or come up with a custom solution.

[@MisterTalkingMachine]

Early LED devices have been my recent obsession (though more of a resurged obsession from my childhood) so this was a treat, even if the diodes aren't that old. There isnt that much to read about the specifics of early LEDs that I can find, I remember there used to be a website that had photos of several unusual diodes, including an early SiC blue LED that had survived a lightning strike. I'd love to see that photo again because now the resilience of SiC LEDs against lightning is more of an urban legend.

[@Jeroen74]

Decadecounter is the website I think you're referring too.

[@MisterTalkingMachine]

@@Jeroen74 nah I've checked that one many times, I also tried to contact them but got no answer. Thank you very much anyway. Why I think it's probably not it, is because there are items I remember being showcased that are not listed there, such as the axial glass LEDs supposedly made by Rohm. I know I didn't make those up because I searched them and bought a couple of them off ebay. I will check on the wayback machine to see if for some reason any items have been removed.

[@johnnytacokleinschmidt515]

Red Skelton! Good tape.

[@MartysRandomStuff]

I had to laugh at the "meant to be taken apart when the plastic wasn't brittle" line, nope, this was never meant to be taken apart.

[@robertlapointe4093]

I have this same clock. Not sure when I bought it, probably between '81 and '86. Still works perfectly, but probably loaded with dander after ~40 years at my bedside.

[@MrCivildefense]

I have had mine just below my television for twenty years. I can read it without my glasses and it's pleasantly dim for use with the tv. Oh how the TV tech had changed in those years and it soldiers on.

[@peterjf7723]

That clock is similar to one I got when I started at university in 1979, maybe I didn't get the clock until 1980, not sure. My clock had a slightly smaller display with two brightness settings that were automatically selected by a photo-cell.

[@fubaralakbar6800]

If I'm not mistaken, I had one of these as a kid : )

[@michaelmoore7975]

Self-stripping screws into marshmallow plastic. (insert screwy pun here)

[@goodun2974]

Michael Moore, one bad twist deserves another? Don't blame me me for bad puns, I'm just trying to put a new spin on the subject..

[@michaelmoore7975]

@@goodun2974 HAHAHAaaa!! Is this soon enough? Am I following you or are you following me? No matter, because I think I know what you're thinkin'. From Psionic to Fran. Yep, it's all about the screws....and electronics. Will I see you on Mr. Carlsons Lab or Uncle Doug or D-lab next? I won't go to the Guitologist anymore.....too much shithouse rattery over there. Or tell me some of the electronics channels you go to. I bet you know a lot of good ones.

[@JeremySeitz]

Next time your dissecting a vintage plastic device like this, you might try coercing it with a heat gun on the low setting, gently warming to soften the plastic a bit. I had success removing similarly annoying fricton-fit-tab pieces like that front lens...

[@JaysElectronicTinkerShack]

wonder what voltage the die are maybe a mod with some tiny smd leds would make it brighter

[@trainliker100]

I wonder if the cut diodes are some scheme making it for 120 or 240 volt line voltage.

[@XMguy]

My grandfather/mother had a Spartus LED clock of that era. Green LED.

[@JonPMeyer]

I LOVE "Little Big Man"! It's getting pretty hard to find a working VHS player these days, but I would consider that tape a nice win anyway! Thanks for more of this very interesting content!

[@BobDarlington]

The TI datasheet for that chip is pretty cool. "The TMS 3450NL is a 4 digit radio clock LSI utilizing the MOS P-channel low threshold, ion-implanted depletion load technology".

[@fredderf6491]

Date code 9244 so clock is 1992 vintage or later ... much better displays are at least 10 years older!

[@justovision]

Last year I bought a clock from goodwill for $2 that looked very early LED. It was a completely different design (It was an Airline) but it had the EXACT same board. The same chip the same sold core wires with the blue plastic spacers connecting it to the display.

[@FranLab]

Yea - generic clocks made for any store chain that wanted their own brand - I have seen many Sears versions of this clock as well.

[@wiseoldfool]

Only part way through, will finish tomorrow, so I may be pre-empting something. I totally agree with your distinction between lens and bezel, but my next thought was how does that relate to embezzelment? Also, it looks like you need one of Big Clive's Spudgers in your tool arsenal! VHS tapes as packing, that's great repurposing! Today is a good day to learn something!

[@lezbriddon]

i'm happy with the word lens, or my favorite , 'filter'

[@annaplojharova1400]

"China" actually often meant Taiwan (other label later was "Taiwan, R.O.C."), The mainland was and is labeled as a "Peoples republic of China" and/or the abbreviation"PRC".

[@JimTheZombieHunter]

@13:00 .. that damned chip again. I spent some time hunting thrift for an old clock that used (I disrecall the number) a National? 40 pin non multiplexed 12/24 HR 50/60 Hz chip, but every one so far has 'that' in them. In fact I've only ever seen one in my life. It's become an obsession.

[@pkuras]

I saw another date code stamped on the back of the LED board - 9302, so the clock itself was built in early January of 1993, about 10 weeks after the chip was made.

[@butchs.4239]

Looking through the eBay listings for Spartus clocks, something like a model 21-3004-500 is more likely 80's era. Smaller LED segments, Hong Kong production, round buttons and slide switches.

[@joedfazio]

LED light output decreases over time, I think lifespan is rated in hours to 1/2 brightness. The clock might have been in operation over 2 decades. I’m sure the LEDs were much brighter when new. Thanks for the tear down!

[@CDP-1802]

Someone wasn't kind, they didn't rewind.... :'(

[@autobotjazz1972]

I owned this exact clock, bought in the mid to late nineties (94-98?) I think at a K-mart which leads me to believe that the molding was reused from earlier design and the clock built as cheaply as possible.

[@signizmz1]

Little Big Man, haven't seen that in years!

[@MrCivildefense]

I could use the battery cover if you want to sell it, mine has been missing since I got it 20+ years ago

[@davidg4288]

When they came out with green LED's I went to great lengths to find a green LED clock and immediately regretted it, it lit up the room way too much at night. I put the red one back in the bedroom and the green one went in my computer room with all the other bright LED's. Then we had to wait decades for blue ones which are a great discovery but pretty annoying indicators IMO.

[@soundspark]

The problem is that green light stimulates the eyes a lot more than red.

[@jrnovosel]

I’ve got one just like it still working on my dresser. I’ve had it forever…

[@KGE64]

You can use the chisel to remove the die's and replace them with some super bright 0805 LED's :-)

[@alvarobravok]

Hi! Why CC again blocked? shouldn't harm you right?

[@stephen1r2]

The boards seem to be phenolic paper though? When did fiberglass become more prevalent?

[@FranLab]

American PCB fabs were using fiberglass in the 70's, but the resin boards are still being used for really cheap products coming out of Asia.

[@jblackacre2325]

Vhs tapes as packing material. Interesting. 😉

[@ErraticPT]

Friend has identical model, branded differently but otherwise identical. 🙂

[@javaking1000]

Fran, what the heck? Two weeks ago you feature the LUMITIME which I owned as a kid, now you have the Spartus, which I owned as a young man - weird!!

[@edb8120]

A cross slot screw like those could be JIS and not Phillips at all.

[@joewiddup9753]

That was my first thought a well. It's probably a JIS.

[@RPKGameVids]

It looks like it's from the 70's to me.

[@thewatchworks1372]

Haha these spartus clocks are ALL over eBay! If you thought that one was cheesy, check out the ones that have a built-in desk lamp!😆

[@adamgh0]

I wonder if the weight of those VHS tapes hiked up shipping costs.

[@PicaDelphon]

You Can Rebuild it Fran..Put Bigger LED's on the Display Board..

[@wmrg1057]

Looks like the Radio Shack clocks I have

[@McTroyd]

Sometimes cheap clocks are cool to take apart. Personally, I like seeing how the vendors do their value engineering. It also helps provide a point of reference for the cool clocks. I feel like a 1982 version of this clock would have used screws instead of the heat stakes though.

[@JessHull]

Were you able to recombobulate it ?

[@kidman2505]

Gotta do the aVe "CLEAR!" when you toss the screwdriver lol

[@ReallifeBambiDeerattheFarm1]

I remember seeing these cheap clocks on sale at Wal-Mart back in the day. Even tore one down to custom fit it into my back pack. ran it on a 9 volt battery (it sucked the power down hard).

[@bad.sector]

Interesting nobody got this yet, but the TMS3450nl seems to be in production since at least the early 80s (did no deep dig, but a chip with '84 date code popped up). So based on this, it's kinda likely this design originates from the 80s.

[@whitesapphire5865]

So what we're really seeing here is Fran, the avid VHS video viewer, has bought two videos, and the seller padded out the box with a digital alarm clock to protect the cassettes in transit! There's nothing quite like crunching noises pervading the air at breakfast time, only it's alarm clocks, not corn flakes, on the menu today.

[@tom95521]

Maybe dim(mer) due to multiplexing. The super bright LEDs we have now are too bright. The LED strobes on emergency/police vehicles is really hard on the eyes. Like staring into the sun.

[@loodusefilm7881]

You should make new clock using that same screen.

[@DandyDon1]

IBM made many PC keyboards this way. The IBM 65, 85 and 95 also had the melt-over keyboard pwb, sigh.

[@SeanBZA]

You can still buy those kind of clocks new, though they have mostly vanished, but there are still plenty of small companies churning out those exact displays, using the old board layouts and moulds for the plastic, and they also buy the lowest cost LED dies now, instead of paying for the high brightness bin, now they want the lowest bin. Still dim, mostly because the chip driver is not the most capable, and pretty much the only thing I see that has not gone COB, the DIP chips must be so plentiful as surplus parts that actually using a bare die is too expensive.

[@cgoad]

Hi Fran. A "ridiculously stupid teardown"? Never! It's a learning opportunity, whatever the result. Thank you for sharing. PS Love a bit of classic Red Skelton. 😉😄

[@thom1218]

I hear Xi Jinping worked assembling clocks in HK in late 70s, so he was pretty forward looking with those stickers I guess.

[@ericlaird1745]

Make something with the LED display.

[@fiver-hoo]

early 80's design, relatively unchanged but production moved to PRC in late 80's/early 90's to reduce costs

[@MyCrazyGarage]

i remember "reverse engineering" a clock like this when i was 9 years old. A few months back a found a "spartus" badge in my attic. It all makes sense now Also i found an even older pcb with strange looking LEDs. They look like wire jumpers in a cross pattern.

[@randycarter2001]

Another factor that affects LED's. They get dimmer over time. Typically they lose 50% brightness after 100,000 hours. A year is 8,700 hours so that's about 10 years of continuous operation. You can see it in that display. The leading one is the least used an it's a touch brighter than the other digits.

[@paulstubbs7678]

So is this what VHS has come to, as valuable as packing 'noodles'

[@goodun2974]

Although not marked as such (no divot punched into the screwhead), those are probably JIS, Japanese Industrial Standard screws, and therefore you need to pick your screwdriver very carefully as the screwheads are easily chewed up and stripped out if you have a poor interface to the screwdriver.

[@flymypg]

**I** am Spartus!

[@hotpuppy1]

It's newer than 80's. I have the same one.

[@empressadria7009]

I didn't think it was as old as you thought but I was wrong too. I thought 1987ish lol

[@scottthomas6202]

The first thing I saw made in China was in the mid 1980s... a flashlight at K-Mart. I had a similar clock in the early '80s....as I recall, the alarm stopped working, and that was a common failure.

[@tmwinkler]

Hey Fran!!! Are you an Amateur Radio Operator??? Would love to see some vids on that topic. 73 K8TMW

[@Oddzball3]

Loving the new videos Fran. Youre an inspiration to me.

[@spehropefhany]

What about bezel vs. escutcheon ? 😀 1980s will probably be marked "Made in HK" or "Made in Taiwan" rather than China, if memory serves (and it may not). Notice all those holes drilled or punched in the display PCB to break the shorts required for gold electroplating.

[@pauldavis6356]

Well I sure learned something - how to use a chisel and a big ole flat-blade screwdriver to open a pesky plastic housing. LoL.