LED watch chip from Texas Instruments (HP 98035 Repair-a-thon Part 0)
ฝัง
- เผยแพร่เมื่อ 26 ก.ย. 2020
- In a previous episode, we decapped a Chinese sourced vintage LED watch chip. Surprisingly, it looked like a legit one. But it still did not work in my HP circuit. What about checking it by making a retro LED watch out of it? Head over to Patreon for the better, but demonetized version of this video...
Edit: I eventually made a bubble LED hack watch out of it: • Bubble LED clock hack ...
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[Update 1:] I made a reproduction of the dude's magic pants, as a pair of jogging pants. Available on my Teespring store at teespring.com/magic-repair-pants . If you wear them while repairing vintage electronics, success is guaranteed!
[Update 2:] I finally found what the 3rd button does! It only works in combination with the READ button. It does two things depending on the clock mode:
- When the clock is in normal mode, it's Clock Stop. That's also what the abbreviation says on the schematic: it's ClS, not C15 as I thought. When pressed and held together with the READ button, it will hold the seconds (for fine time adjustment).
- When the clock is in adjust mode, it can be used for quick advance. When the READ button is held down or pressed repeatedly, it advances the numbers, but very slowly. However, if you pulse the ClS button at the same time as you hold READ, it advances instantly at each ClS press. The Nanoprocessor uses this to do the super fast time adjustment you'll see in the next episodes.
I found it the hard way by reading the ROM code.
Next episode: Marc realizes he's been wearing the wrong pants this whole time, and that was the only real problem.
*70s music intensifies*
you mean : the wrong trousers ?
(Wallace and Gromit intensifies)
Those led arrays are so pretty. Like little digital jewels. We need to bring those back in every color.
it looks pretty only if watched with a macro lens capture on a large computer screen...
I still have my grandfather calculator (RPN please) which used this very same display. It still works as far as I know, but it's so tiny it make the thing difficulty usable.
I have many ideas for just that - - a red LED wristwatch that duplicates the form, functions, and display aesthetics of these early digital watches.
I would love to see an LED matrix display with modern GaN LEDs. The brightness would be insane even at low currents. Maybe I need to watch for a wire bonder on ebay.
@@davidwillmore But they are made. Search for HCMS-29xx series - this is smart module, 5x7 dot matrix. If I am not mistaken, this watch is made with them: steampunker.ru/blog/usersworks/13375.html
Well you might be surprised to know that the modern led array that you observed while making this conclusion is actually capable of the same feat and also in every color.
1970: computer taps into 7 segment driver lines.
2020: computer uses cloud-based OCR service with AI tacked on, working on images uploaded from a web cam pointed at the 7 segment display.
2015 : use a Linux-based Raspberry Pi to blink a LED
@@leyasep5919 the 4Gb quadcore version of course
@smakfu the future is so amazing...
Dont forget that the webcam has to be the one that all UFO sightings are taken with
"You're as much use as a digital watch to a one armed man"... There's an insult that had a very short shelf-life :-D
An insult that died out when the LCD was invented.
@@BlackEpyon That's the one. :-D
I bought two of those TI watches when they came out, $39.95 AUD, one for me and one for my dad for fathers day.👍👍👍👍
_Marc, you answered my long-time question at _*_17:53_*_ by showing that these bubble displays _*_CANNOT_*_ be butted together on a breadboard, and must be spaced one hole apart. _*_Thanks!_* 👍
I'm now convinced Covid is a plot to make Marc build a quantum computer time machine or something out of vintage HP parts.
Some LCD clock chips are even sneakier with their segments, using a shared output for the top and bottom segment of the tens-of-minutes digits, since it never needs to count to 7, which is the only digit where the top and bottom outputs would need to differ.
I just mentally cycled through the 7-segment digits and you're right! How the hell had I never noticed this?! Mind blown.
fun fact: first dot led were so small that manufacturers put a lens between them and the exterior bezel; if you watch carefully the pictures in the first minute of the video, the red lit digits look a bit distorted, that's the lens magnifying the figures
the LM8361 does this.
@@alerey4363 That's exactly what these bubble LED chips do. The 'bubble' is a lens.
2:00 - the catalogue technicians trousers are out of this world! Wow.
Flares/huge cheques the whole thing :)
I busted out laughing when he pointed out the dude's pants.
It's as if some inexplicably important and powerful "influencer" in the early 70s said "clown inspired fashion, yes, that's the future!" and just went with it. The horrendous patterns, the enormous ties, the ridiculously huge pointy shirt collars, the polyester leisure suits.... There is little other plausible explanation.
did you go "HA! HA! HA! HA!" ?
@@codefeenix 2:09
@@Muonium1 I don't know, the photo in question is fairly aesthetically pleasing
"Of course half of the magic is these wonderful pants, here," plus Bee Gees equals laughter from me too. 😄
My mom gave me one of those watches in middle seventies, but I think it was from Casio. Years after I had a HP-33E calculator that, I think, used the same display chips.
And, of course, the old good Texas handbook that I used until desmantled. Good memories! Thank you very much!
I'm from Brazil, by the way.
Very impressive detective work! When I was in high school we had an HP 9830 with card reader, plotter and thermal line printer. It didn't use data cartridges, it used data cassettes. Regular audio cassettes worked too.
"I had my brain and the LED rewired". Priceless!
and the LED were OK all along :-P
Wow, that's a trip down memory lane. I had one of those TI watches in like 1976. I discovered that I could hear the mux tone with a telephone pickup loop and audio amp. It was cool because it changed slightly depending on which segments were being illuminated.
Years ago i had a old computer made 1989 in (East) Germany.
It was a P8000 Compact with optional real time clock which used the same principle.
They put a chip from a LCD watch on a daughterboard and grabbed the the output from the segments.
Some CMOS logic chips were used to connect the board to the system bus of the computer.
This are mainly address decoders and buffers.
They used only five of the seven segments because this is enough to recognize each number.
From the first (hour tens/month tens) segment they took only two segments.
The decoding of the time and setting of the clock has to be done by software.
To set the clock and to switch the display you normally have to press three buttons.
You have to emulate this by software!
The watch chip has various display modes: time with day, time with seconds, stop watch, set mode(s).
The clock board is the last part that remained from this computer.
The computer himself was scrapped in the early 2000s.
Because this real time clock board is a collectable item, i saved it.
Finally in 2018 i managed to get it working again.
I connected it to a microcontroller which emulates the data bus of a P8000 system.
But: On 1.1.2020 the calendar rolled over from (20)19 to (19)80.
It works still today and is relatively precise!
Thanks for your extraordinary work at keeping historical computing technology alive and properly documented. What you do is priceless.
I also have one of those gorgeous HP 59309A clocks. Nice piece of "horology" of you can even call it that. Waited for one on eBay for almost a year... Then found one in some dudes garage buying some other old HP equipment. $20 bucks.
HP, putting the 'real clock' in 'real time clock'...
Literally.
Thank-you for making a distinction between Hong Kong and China.
Seems like the kind of guy that has probably been to both.
OMG are you from Hongkong? Cool!
This is the best TH-cam video in the history of TH-cam 😀 amazing detective work. I had one of those watches! Its kind of amazing that HP figured out that the most efficient way to get a real time clock was to get a cheap digital watch IC and screen-scrape the digits. (Also amazing how big the circuit boards were just to do that one thing). Thank you for this video!
What a wonderful nostalgia blast! My best friend in grade 6 had an LED watch, and I was SO jealous! This was so exciting to "watch".
Thanks for making this action investigation video Marc. So satisfactory to see a vintage technology come to life.
Breadboard wristwatches are going to be all the rage now. Takes up the whole forearm, but looks cool.
This is AWESOME. I love your intelligent analysis, and ability to figure out black boxes.
Oh wow! I had the keyboard to one of those HPs as a little kid (6? 7?) that my dad brought home from work for me to play with. It was just the top case frame with the keys in it, but boy did I get a lot of fun out of imagining things with it.
imagination is the root of creation !
what did you engineer since then ?
@@leyasep5919 I went into the support side of the IT business, but my son has a deep interest in the nitty gritty like this stuff, and that's sort of wearing off on me. He's been working on a BenEater 8 bit computer for awhile now, so I've had to catch up on my learning to keep up!
I had one of those watches in the 5th grade. 1977 I believe. I used to take it apart in class and marvel at it. It was fascinating to me.
Hey Marc I love your method of troubleshooting by building something different with the repair parts! That's what I do all the time.
My parents gave me a TI watch in the summer of 1975. They bought it at KMart and gave it to me to wear when I started high-school. Good times.
I loved those old LED watches - tiny little bubble LED display and it only stays on for a second or so when you press the button - you need both hands free to be able to tell the time - in bright sunlight you can't see a thing - totally dysfunctional yet cooler than a really cool thing. That HP desktop calculator is rather nice too - so many buttons - more buttons is just better!!!!!! Great video Marc :-)
Seen those pants and waited for someone to yell “tequila”. My dad had one of those early led watches, thing was a brick on his wrist.
Brings back memories when I was a kid building circuits on my breadboards... My clock chip of choice at the time was the MM5316...
Thanks for keeping it light just like in the 70's!
I remember using the HP9825B and that clock module back in the early 1980s at Motorola to develop a semi-automated lab test setup for tractor electronic instrument panels. Very neat explanation. Crazy they decoded the seven segment patterns to read the data!!! Bad battery charger design. I just wrote some multiplex code for Nixies using similar techniques at higher voltage, of course.
Texas Instruments also made these lovely "Display with Logic" ASCII Displays.
Marc, thank you for this great content !
Wow! You seriously know your way around those old IC’s! 🤗
Nice. I love this kinda stuff. Takes me back to the early 70's when I just barely graduated from toddlerhood and was disassembling Coleco Football games and such to figure out how they worked. Took apart everything as soon as I got it. If I wanted to play with it I had to (after learning everything I could about PCBs) correctly reassemble it.
Way to troubleshoot that out Marc! Nice going! Love this vid!
Very well presented. You are so much fun to watch and listen to.
Brilliant! This is my era of circuit design :)
I spent a lot of time programming in HP Basic back in the day, loved the HP9825 - thanks for sharing! The version I used had a 2 row 80 column display... and that tape drive... omg. Only thing I hated was the thermal printer (the printout would fade over time).
Your videos are some of the best technology related content on TH-cam.
I'm much more interested in things like this anyway. Logic chips are more fun than writing microcontroller software.
Excellent. I collect early led watches. A novel use of the Ti chip :)
Super cool displays, Marc. I currently need displays and those are giving me ideas. Those definitely are not cheap nor widely found as you mentioned. Figures HP did in-house production for those. Quite the saga on the board fixes. Those pants had to have helped with the repairs haha.
Every time I see a vid and think yep, that's for me, it turns out to be you! In this particular video I recall having a 'digital" watch, as a 15 year old. I still have a fascination with the HP bubble LED displays. I bet those flairs were yellow, I wanted but didn't ever get a pair.
Interesting flashback to the 70's. I remember the first time I saw one of those red LED displays at some show room in NYC in the early 70's. I think the display was of some simple pocket calculators so the show room might have been set up by TI since they were the first ones to make handheld calculators in the beginning I believe. Anyway, my dad was an old school engineer and a master of the slide rule, and he wanted to see one of these new-fangled gadgets. I imagine they were only capable of add, sub., multiply and divide functions so I don't think he was impressed but as a young kid I thought they were very Buck Rodgers!
Always a treat to watch your content.
Love it. Love those bubble leds.
3:38 when board density was measured in blocks per board.
Those bubble leds are beautiful. I inherited a 4 function calculator that used them that my grandfather owned.
this was really cool, my grandpa was one of the lead engineers on one of the other first LED watches. I don't know if it was before this one or not but it was really similar and it wasn't TI. I remember a bunch of his stories about sourcing the tiny LED displays and simplifying the logic needed for the clock functionality but I don't remember the exact year that he was working on the project. If he had given up the cigarettes and alcohol maybe I could still ask him...
Talk about getting sidetracked :-) " There's something wrong with my HP clock module, the clock chip is working just fine but
lets spend a couple of days and order more parts to build a clock on a breadboard that I won't use to anything!"
You sir are a french version of me. :-D Great video as allways! Big thumbs up !
CuriousMarc presentation: Never gets old.
Bought my wife an LCD watch for Mother's Day when they first came out (1976) -- $150. Display stayed on all the time!
A vintage chip that isn't fake.... almost unbelievable these days. Great video... That was an enjoyable watch.
Superb Marc... love it!
Oh wow. I had that orange TI databook in the early 80s when I was a kid and were trying to learn what TTL was all about. I still have it somewhere! Looking all misty eyed at the unobtainium PROMs.
Very nice my brother. You’re one smart dude.
I absolutely love this channel! Great video, man!
Surprised it's still Stayin Alive after all these years. :)
Bubble LEDs are so oddly satisfying, I found a very basic 70s HP 3476A bench meter that uses them.. terribly outdated, but I couldn't pass it up for $10, just looks awesome.. The weird 70s futuristic case, bubble LEDs, and clunky ganged switches
codefeenix They look neat... Personal preference?
That was great, those modules are beautiful. Also lol @ the magic pants.
The engineers behind these chips are pretty damned smart. Even in the early days, they were quire complicated to design, let alone build. Pretty neat.
my first comment was " wow... those pants! " I am pleased you made mention
Yes, I approve of those bubble LED packages. They are lovely.
This episode is a true time travel. Cheers from Belgium ;-)
It was funny to watch. Thanks for doing this great series of videos.
Very cool, man. Keep us updated. 🙂
A technique I use to help detect obvious fake chips is by using VI curve tracing on each pin, comparing the results to a known good device. Good for detecting certain types of damage to ICs too. I have test equipment that actually runs a “matrix VI” test where each pin is curve traced in relation to each other and the results stored automatically. I can then later test another IC using the stored results and any differences automatically highlighted!
codefeenix If you search for “SYSTEM 8 Advanced Matrix Scanner” you’ll find a later version of the device I use (System 8 AICT) but it appears to be purely VI tracing. The AICT has fewer test channels and can test analogue ICs in circuit such as OP amps and transistors as well as VI curve tracing.
The 70s music cracked me up
love the pants! time for the 70's revival!
This invoked a long ago memory of being a kid. Parents brought me a digital watch (6 million dollar man I think) for Christmas. By Christmas night the battery was flat!!
Excellent! Thank you for posting
Wonderful stuff
Those bubble LEDs are beautiful ❤
To be fair, the modern 7-segments come in both common cathode and anode - if that's what you want.
When you fix the HP, it may be worth adding something like a 3.3V zener across the battery so that any future battery failure won't zap the clock. Pity HP didn't think to do that.
A low voltage zener is completely useless for this application, they have very soft knees so will be passing a significant current at voltages much lower than their 3.3v rating. As an example a 1N5913B will be leaking up to 100uA at just 1v reverse bias, and obviously quite a bit more at the 2.5v nominal battery voltage. Something like a TL431 would be a far better solution.
What @SkyWizardless says. Obviously you can’t do the zener because of the high quiescent current consumption.
@@CuriousMarc I suppose devices like the TL431 were not available to HP back in the day. They could have added a zener to the charging circuit though, via its own diode to the battery.
@CuriousMarc Three-terminal TO220 regulators like the 7805 were brand new back then. There were no low-leakage regulators or shunt regulators like the TL431 that I recall and the available regulators had quiescent currents way too high for battery operation. I suppose the designer (I forget his name) of the 98035A could have used five silicon diodes in series to clamp the clock chip's Vcc at 3V or so, but that would have taken some room on the board and frankly, none of us were envisioning that our designs would be in use 40 years after introduction.
@@sleibson Agreed, the design makes complete sense in context.
Those small LEDs are rally nice.
Interesting, the tied-together tenths place of the looks a bit dimmer.
It could be the module but I suspect it's because the current is divided between two segments.
Is this also happening on the original watch?
I'm not an electchicken but the way you explain this stuff makes it so I can understand it :D
the secret is ...
it's not *that* complex in principle.
the theory however is often idealistic and the practice introduces quirks that make it look complex.
but the idea is often simple.
Great work !
So cool. Love your videos.
Great work. I had some Comon Anode 7-segs from China that had the "Superbright" LED segments and they would easily have run at 1ma from what I remember. Still the little Bubble LEDs are way cooler.
I like how the "1" is dimmer than the other digits because two segments are splitting the same current as goes to each single segment of the other digits.
I'm going to make one also. Many thanx.
Awesome video thanks
In the 70s as a kid, my first watch was a Timex LED.. press the button to see the time... same as my current watch.. a Gear S3.. For all the change, some changed back...
Closest I've come to this is getting my old '76 Bulova LED watch up and running... but thankfully that was more a matter of removing the old batteries and cleaning all of the switch contacts!
Great video
My dad bought of my first led watch Xmas '76 it lasted less than 2 weeks on the first battery!
I remember, playing with such bubble LED chips, figuring out which way is the proper orientation (thus finding pin 1) by looking under bright light to see the decimal point on the unlit display.
You mentioned HP being a leader in tiny LED displays at the time. Could the TI watches be using HP displays, or would they be able to make those in house as well?
I'd guess that HP was TI's supplier of 7-segment LEDs at the time, and is why TI was willing to repackage their clock chip for them.
What?!?!?!?
No paper clips or dremels?
That was a tough one.
i want to forget 😢
every one has a bad day.
But the 8-bit guy is so likable. This is about this I presume: th-cam.com/video/Wh2OCBZpzZ8/w-d-xo.html . People already figured out that his graphics chip needs help and that the computer was simply waiting for the special PS/2 bootup disc. I’m sure he’ll get help to get that thing going.
Be nice
Very Nice !
Excellent, just excellent
These LEDs are nice to look at. Wouldn't mind wearing a modern version if they existed.
Great my first digital ti watch. I still own it. It ate batteries like crazy... but i never wore those pants
2:16 lol half the magic is because of the pants, best comment about vintage tech EVER!
I'm glad, you found my displays beautifull :D
Hey thanks! Nice to see you here!
Excellent !
Hughes Aircraft was another huge competitor in this space. Up into the late '70s they were the world's largest producer of LED watch modules.
Thanks, I did not know.
I'd be surprised if you couldn't drive a modern 7 segment display to a readable brightness, modern LEDs are orders of magnitude more efficient than the technology used in that era.
I was thinking that, but it's cooler with the older style chip.
Or make a XOR comparator between 7 segments and those generated by clocked BCD counter, strobing BCD address when those match - thus making BCD from 7 segment and multiplexing nixies with aditional MPSA transistors :D
When he tested the display he said he was driving it at 1ma, technically that will light a normal modern led but you'll have to turn the lights off to tell.
How do you prevent the batteties from leaking again once you replace the leaking ones with the new one?
I have a lot of computer motherboardss with this leaking 30+ year old varta batteries and once you replace them and clean the damage they have done, this can happen again, causing more damage
I heard of watching youtube videos but this is nuts!