I love when people document these black boxes.

next episode: Master Ken rebonding the Chinese chips and Chief Antoine baking them into new packages, so they can use them as spares in the future or sell then on the "Interweb".

@1944GPW

4 жыл бұрын

Send the dies to Sam Zeloof as a challenge. If anyone could repackage them back onto a DIP, he would be the most likely to succeed :)

@manuell3505

4 жыл бұрын

11:45 I guess he wants to keep the original hardware, but wouldn't it be possible to emulate the clockchip output bits correctly with programmable logic?

@johncrowerdoe5527

4 жыл бұрын

@@manuell3505 Not many programmable chips matching the peculiar voltage and power characteristics. That said, back in the day Ti had an official digital clock chip with LED drivers, apparently based on a mucrocontroller. It was used in at least one magazine published "build your own digital clock" project.

It's always great to see chips under a microscope, can't wait to watch the next one.

@dave68

4 жыл бұрын

Yes, and I for one would love to see the "Donald Duck" drawings, and the like, on the edges of some of those chips. Bored engineers.

Strong suggestion from someone else that has had fried chips due to OV when the battery dies and goes open: put a zener or forward biased diode string across the battery or chip Vcc voltage to keep a future battery failure from doing the same thing.

@CuriousMarc

4 жыл бұрын

Exactly. I really wonder why they did not do it. Maybe worried about the extra leakage current and wanted to keep it at an absolute minimum?

@lwilton

4 жыл бұрын

@@CuriousMarc Possibly. Since that lack seems to be endemic to this sort of stuff no matter who made it, I more think that it somehow just didn't occur to the engineers that the battery could fail, or maybe it got cost reduced out by a manager. On the other hand, low voltage zeners have really sloppy regulation curves, and might well draw significant standby current at 2.5V. A stack of forward-biased diodes might be a better choice. What's the charging voltage on those batteries? It must be more than 2.5V. Hopefully a clip around a half volt over the charging voltage would be safe.

@simondann7371

4 жыл бұрын

l wilton I reckon it was assumed by the time the problem occurred the product would be end of life.

@nophead

4 жыл бұрын

@@CuriousMarc I expect the charging circuit might feed the battery with a diode, so it doesn't drain it while off. In which case you could clamp the other side of the diode and not increase the leakage while off.

@ferrumignis

4 жыл бұрын

Low voltage zener diodes are effectively useless for this kind of protection as they have such a soft knee. This means it either clamps at a higher voltage than you want or you have to accept a considerable leakage current at the nominal voltage.

Yeah, given that I was doing a fair bit of work in VLSI in the late 70s - early 80s I was kinda expecting to see I^2 L (I squared L) in the clock chip. I2L is very low power and a lot of watch chips used it back then. CMOS was very much in its infancy in the early 80s and the working voltage was too high (over the 3v of two watch cells) back then. Really fun video

@BlackEpyon

4 жыл бұрын

Did you happen to be involved with making any of the VLSI chips that Tandy used?

@ksbs2036

4 жыл бұрын

@@BlackEpyon , sorry no I wasn't. I was a research assistant at the University of Waterloo's VLSI group. We were figuring out how to design them. The chips were following Moore's law so the capability to make lots of transistors was outstripping our ability to make designs with lots of transistors ...

@BlackEpyon

4 жыл бұрын

@@ksbs2036 The reason I asked, is because the VLSI chips on those retro computers are pretty much black boxes. The service manuals told you what was in them, and the pinout, but not the schematic diagram internal to the chip itself. They were pretty reliable (I've never seen one go), but if one happened to go, you'd have to find a donor board to salvage from, 'cause there's no way to replicate them.

@DanaMyersK6JQ

4 жыл бұрын

These are more early-mid 1970s vintage, right?

@VintageTechFan

4 жыл бұрын

Working voltage too high .. Wasn't that the case for MOS in general at first? I mean, early NMOS and PMOS chips ran at basically 17V, the +5V/-12V for PMOS and +12V/-5V for NMOS were only to get (somewhat) TTL-compatible logic levels? The 4004 for example doesn't even have a "GND" pin? The couldn't implement depletion mode FETs on the same die as the enhanced mode back then, so that the current source FET used considerable voltage if I understood it correctly?

Maybe the problem is how they get those chips, while doing that destructive process that is documented somewhere on KZread (they take a board, pass it on a puddle of molten solder and then slam the board against a surface until the chips break lose) the bonds to the silicon bit break, or maybe ironically they are taken from the same boards as the one you're trying to repair and they are already zapped 😂

"It took master Ken only 2 clock cycles to identify some very unusual 1970s IC technology." lmao only 2 clock cycles that was fast

@UnitSe7en

4 жыл бұрын

Not necessarily fast. It depends on the speed of the clock.

@DouglasJohann

4 жыл бұрын

Well you got me. You're right!

@volo870

4 жыл бұрын

Now we know that Ken is hardware-optimized to identify unusual 1970s IC technology.

@madmax2069

4 жыл бұрын

@@UnitSe7en I was going to say the same thing

@eloyex

4 жыл бұрын

Ugmmmm ......... Ken seems to be a Schottky fast dude. .....!!!.

Thanks for making my day. It is simply fun to watch professionals at work. What a pleasure and yes: I have learned a lot again without ruining my own stuff.

These videos are definition of perfectness. All of them are really made my day. Thanks for the team and you. Please continue sharing.

"FOCUS YOU FAC!", one old canadian proverb says

@jpolar394

3 жыл бұрын

AvE........😆😆😆😆😆

What are the chances that the Chinese were real, but toasted in exactly the same way?

@petergorelov418

4 жыл бұрын

Actually, I thought exactly the same ;)

@MrFathead

4 жыл бұрын

That was my first thought. Since the chips appear real and the fault it so common it would make sense. We will have to wait for them to make a test board to find out but my money is on the chinese chips being faulty.

@Membrane556

4 жыл бұрын

I was thinking the same as they're probably pulls from recycled hardware. Too bad HP didn't add over voltage protection circuitry for the chip. But then they probably figured the battery would last longer than the service life of the equipment.

@Troppa17

4 жыл бұрын

@@Membrane556 Exactly what I thought. They pulled the chips from faulty HP RTC moduls or other HP equipment. Maybe they simply didn't know about the problem and assume the chips were working.

@Broken_Yugo

4 жыл бұрын

Very high, it's my understanding all these vintage chips out of China are at best pulled from scrapped gear and sold with no testing, maybe erase the EPROMs. At worst they remark them as a faster or more favorable variant.

I would start looking at the traces etc where the batteries leaked on the boards. This is very common for early digital pinball boards, we have found some very creative ways of fixing it.

I've tried this die removing technique and I always crack the die! I'll keep trying

@dave68

4 жыл бұрын

Practice, and patience...

@jkenny1

4 жыл бұрын

You can try sandpaper and a lot of patience too. Start coarse and work your way down, like polishing. Then scrape off the last part with a plastic spudger. I've got a video on my process on my channel.

'I want to control my HP power supply in style'. There are only three things in life that really matter: Style, style and; of course; style!

I've brought hundreds of older chips from China. I normally stick to the same few suppliers I know a reliable. I've only ever gotten a batch of fakes once once I let the seller know they pulled them from sale and sent replacements, I still buy from them today. That time they got sold fake chips from a new supplier.

@64bittz93

2 жыл бұрын

Is there any chance you reveal your trusty vendor?

They don't make fake chips like this, they recover, clean, sand and remark chips to be sold as new.

@gkasprow

Жыл бұрын

they sometimes use low-grade opamps marked as precision ones. They also make functional copies of popular chips - search for "FTDI chip gate"

@Gerardus1970

Жыл бұрын

@@gkasprow Yes, and a lot got caught out by that too, bricking their devices.

I2L logic? That brings back memories. When I was a university student (some 30 years ago) I had to work a couple of months on a project for a semiconductor company. The project consisted of creating simulation models for I2L building blocks by parameterising test structures. So it was analogue work, resulting in a digital simulation model. I2L logic was preferred as it was used for small digital control blocks in otherwise entirely analogue bipolar products. The wafer technology was bipolar, so MOS logic was not available in these mixed signal products.

@manuell3505

3 жыл бұрын

So you measured the behaviour of existing circuitry to refine your own product? If it was from a different manufacturer who was unaware of it, isn't that reverse engineering?

@windmill1965

3 жыл бұрын

@@manuell3505 The company had an in-house simulation tool. Which could simulate for example the influence of supply voltage, temperature or deviation in manufacturing accuracies, in the performance of I2L logic. The accuracy of the simulation results depend of course on how accurate the simulation model is. So the characteristics of the pn-junctions and the transistor behaviour were measured using special test structures and then used as parameter settings in the simulation models. This is the work I had to do: measuring those test structures, finding the correct parameter values, and then verify the simulation results with actual I2L performance. It had nothing to do with reverse engineering chips from other manufacturers.

@manuell3505

3 жыл бұрын

@@windmill1965 Allright, that's just an independent research/production circle.

Dr. Ken should write a guide of how to identify a chip production date based on its technological features. With illustrations.

In Chine they have factories where they will take old chips from recycled electronics and lazer etch the surface of the chip to make it look new and change the printing on the chip to make it look like the newest version of said chip with the newest firmware. Then they will sell them as new old stock etc, when they are old used, and may not work.

Check out those vintage Friden's in the background! Mechanical calculating machines. Used them in college and first job before electronic calculators came on the market.

@CuriousMarc

4 жыл бұрын

This playlist has the videos about the Fridens: kzread.info/head/PL-_93BVApb5_GbzkFwdKpuyPo8Ty83h8b

"So at one point, I wanted to flex even more". Too funny!

Can’t wait for the video about how you test the HP RTC module and if none of the chips work how you emulate the chip in an FPGA or Arduino. Grabbing the popcorn 🍿

in shenzhen, they list every chip online, when an order comes in, they write the correct name on something with the same package, sometimes a close model number, or shorted out, or sometimes reprogrammed years ago a us pilot's ejector seat did not work, and they concluded it was fake chips. manufacturing only tested some of them, and did not see any bad chips😢

Fascinating. You do magnificent content. Thanks for taking the time to share your passion.

If memory serves me... I2L was way more prone to static discharge damage, more so than even early CMOS ?

@ksbs2036

4 жыл бұрын

I don't believe so. It is a bipolar process so it doesn't have the gate insulator that gets destroyed when E-field go to a million volts per metre. (1 volt across a micron)

@SeanBZA

4 жыл бұрын

It was a lot more sensitive to process errors though, especially in the early days of IC manufacture, as it relies on barely turning diodes on and off to do logic. Power hungry as well, so those early wristwatches had a very short battery life, even if you did not turn the display on.

@SeanBZA

4 жыл бұрын

@@MikinessAnalog IRFZ44 likely has, in addition to humongous internal capacitance in the gate to absorb ESD current, a set of zener diode clamps to limit gate voltage. The clamps are around 20V, so they do not otherwise affect the decice in operation, and the capacitance is why the drivers need to be so robust if you want fast low power dissipation switching. DC to a kHz you can use a regular logic gate drive, but for higher frequency the current peaks required increase quite a bit.

love the noise of the computer starting :D 4:17

Insanely interesting! Thanks for sharing!

I put my thinking hat on before watching... Intriguing investigation work. Good job all.

If you decap a chip that has been "zapped" by 2X overvoltage, would the damage done not be obvious when viewed under a microscope?

@dave68

4 жыл бұрын

@CuriousMarc were the chips zapped? We couldn't tell from the microscopic images.

Can't wait to see the next chapter in this treasure hunt!

Since it's remote piloting a watch could another clock chip with LED drivers be adapted or a uC programmed to emulate it?

Brilliant analysis as usual but I have to say I cant imagine any Chinese copier being able to make a chip like this with such limited resale. I decapped plastic chips many years ago when running a thick film lab and the New Zealand department of scientific and industrial research laboratories and have a very reliable method but I cant find the paper I used to make my version. I am truly surprised it isn't used these days, It involved boiling nitric acid but it was very safe ( as far as nitric acid goes ) and worked incredibly well. I can explain it etc but I would need to give you drawings etc so I would need to talk direct via email if you are interested

In the scene where you were explaining this cartridge with the battery and chip that you wish to replace, there is what appears to be an old white ceramic ic, a really large one. Would your friend’s ‘heatgun and break in’ style of retrieving a die be as reliable on these older heavier ceramic styles of ic? I’ve noticed that those ceramic ICs often have layers sandwiched together and those layers are different shades of grey, brown, white, and black. As usual, great stuff, you make some really educational content, while really keeping with the entertainment factor, at least for independently produced and as close to reality as it could be!! Thanks again!

@AngelaTheSephira

Жыл бұрын

It would probably be real easy, as the gold lid is soldered on the top.

At one point the Soviet's were having agents purchase speak and spells to take home to copy chips. Many of these chips were copied including the manufacturers logo on the Soviet clone. They were that far behind that Toys R Us was a source for tech that did not have.

is master Ken actually human 😂

@CuriousMarc

4 жыл бұрын

I have my doubts.

Marc, i think we have a hp9825 at work? If its available and that model and isf so would you like it? Will check next week.

It should be easy enough to build a replacement that plugs right in with an Arduino. Sure I get the idea of keeping it original, but at some point...

I wonder if a small form-function board could be designed around a small microcontroller to fit into that socket. Perhaps not the usual AVR or PIC, but maybe an MSP430 with its LCD drivers adapted for this sort of usage.

Excellent content.

This is what I wanted to do. I did a mod on my phone camera with a 8mm or 6mm CCTV camera lens and I was able to decap my bank reader IC and made a low res photo of the die !! Never would have imagined this was possible (few years ago). But now I want to know as well. I brought TNY180 power switch ICs for dirt cheap. Are these ones real or fake?! Maybe I decap a "new chip" and try to compare this with the half burnt up chip. Maybe I can see similarities ?

Wow really interessting video !

Just a suggestion, have you tried contacting TI to see if they can help you?

@johncrowerdoe5527

4 жыл бұрын

Great idea, Ti is keeping lots of old designs available as normal stock numbers, so they may well be keeping other historic chips on file or in stock, but on request only.

what a great scope.

Fascinating

Hello, mr.Mark please tell me what is that laboratory , where you are working?

11:11 your comment about cleaving silicon got my attention. Want to add that it is hard handle because of how brittle it is, but it is not hard to cleave. We usually mark the silicon with a diamond pen and just shear it off, putting it on a paper clip. Cleaving sapphire or silicon carbide wafers is way harder. P.S. Will Master Ken reverse engineer the circuitry of this chip?

@thebigpicture2032

4 жыл бұрын

Yes, silicon cleavage does get one’s attention.

@eloyex

4 жыл бұрын

hehehehe , love the "Master Ken". comment ... the guy deserves respect !

@VintageTechFan

4 жыл бұрын

@@thebigpicture2032 Google gets many search requests for this particular thing, though. Mostly from us Germans ;).

What microscope was used here?

lucky guys with a reflected light microscope !

Cool video. How come HP didn't use a voltage regulator with the clock chip?

@davebing11

Жыл бұрын

the leakage current of the voltage regulators back then were well over 10uA which was way higher than what the clock chip drew

Can anyone explain the colour difference between the two intact dies? Could it be down to a very slight difference in the thickness of whatever coats it?

I remember the Soviets would copy US processors right down to the manufacturer name on die so not a guarantee it is original. If their is a market for them they will do it

Lol potato vision. Sir... I do believe you have introduced a new visual standard of awesomeness 🙂

Could you possible post a link to the decapping video?

@CuriousMarc

4 жыл бұрын

Here: kzread.info/dash/bejne/jIWZqqqSery9iNI.html

Dear CuriousMarc, Can you identify the part of the chip that was blown by over-voltage? Just curious if the damage is visible under the microscope.

@MrFathead

4 жыл бұрын

I was thinking that too, it would be interesting. But it might not even be on the die where it melted.

@CuriousMarc

4 жыл бұрын

No, could not see anything obvious.

@jkenny1

4 жыл бұрын

Failure analysis is hard.. dealing with it at my day job. There a whole host of testing and analysis methods including thermal imaging and SEM. Fascinating stuff though.

@volo870

4 жыл бұрын

@@CuriousMarc, thank you for your reply.

I thought this video was going to be about old maps

What's left is to plug the Chinese chip and hope for the best... which is kind of saying PnP MS technology, Plug and Pray.

Those watches sold for like 5 and 700 dollars at one time.

@wolvenar

4 жыл бұрын

@rustybuttpate I had nearly the same experience. Damn....we are old now aren't we?

Reminds me of circuits that blew the SCRs or TRIACS in order to protect the fuse. :_)

@wesleymays1931

4 жыл бұрын

Maybe blowing a BGA LED driver to save the fuse?

so i'm the only one that gets fake parts (transistors)... anyways the new chips may have been salvaged from a computer or else that have sockets for at least the RTC and may had the same problem with the battery, so fried as well

@medes5597

4 жыл бұрын

I get fake transistors too. Also I got fake resistors about a year ago - literally they'd put correctly coloured plastic on a piece of wire. I was like "what the actual fuck".

@jkenny1

4 жыл бұрын

The interesting ones are fake FETs I've bought that are fake, but still functional and similar characteristic. Must be made from a Chinese manufacturer to similar specification and just remarked for higher price.

@redoverdrivetheunstoppable4637

4 жыл бұрын

@@medes5597 i bought a 2500pcs pack of 1/4W and they were not metal film and not inside the 1% stated obviously, more like 2-3%, but i use em

@redoverdrivetheunstoppable4637

4 жыл бұрын

@@jkenny1 if they are fake they quite likely withstand less current, they put a smaller die inside and that's how they scam you, buying from a more costly seller seems to not solve the problem, weirdly they sometimes provide you good parts, so the price may be near to the correct one, i would be perfectly happy to pay 1.5X times the price but have good parts, another funny fact is that they CAN provide you LEGIT parts but without fancy brands, infact inside their gadgets they usually fit legit unbranded parts, i also found a custom made transistor, if you buy an high voltage module like the 15kV one, between the components there's a BJT with package TO126, but to copy the pinout of a TO220 that has been replaced for cheapness they made an unmarked, unknown TO126 transistor with pinout b-c-e like a TO220 that as far as i know doesn't exist, TO126 are all e-c-b, so they can make a custom transistor just to sell some junk modules

I'm no expert, but could the Chinese seller have somehow gotten hold of a bunch of chips that TI dumped because they were defective?

@sittingstill3578

3 жыл бұрын

I heard in an _Adrian’s Digital Basement_ episode that many of the authentic chips from China were acquired through e-waste processing.

mr. claunches idea of building a testing board being the pro thing, wouldnt it be fun to wire a star wars watch pcb into the hp machine?

Oh cool... just randomly was notified of this video and there I see the 1820-1691 nanoprocessor or in it.

@williamsteele

3 жыл бұрын

Handwritten voltage of only 2.5v... wow!

What would be even more interesting, is to see the chips working under the electron microscope

@BlackEpyon

4 жыл бұрын

Pretty sure that would make them stop working.

@mumiemonstret

4 жыл бұрын

@@BlackEpyon Applied Science does it with a 555 timer: kzread.info/dash/bejne/l6OGuKewZcqyaMY.html

@lbochtler

4 жыл бұрын

@@BlackEpyon its a technique thats used to test chips. Though it depends on the technology if they can withstand it. Also, a proper electron microscope dose not destroy chips as easily as applied sciences hacked together SEM did, if you where basing that off of his video.

@BlackEpyon

4 жыл бұрын

@@lbochtler Applied Science got himself a proper SEM too. I was thinking more along the lines of the die being bathed in electrons and just washing out. It wouldn't be able to function WHILE it's being scanned, but should be able to function afterwards. I think.

@lbochtler

4 жыл бұрын

@@BlackEpyon The technique that is normally used is EBIC (Electron beam induced Current). You wont see it run in real time though, as you need to scan rather slowly. Yes, i know Applied Science has a proper SEM as well, but i dont recall him trying the microchip experiment using it

Please see this for additional info and a thorough tutorial on the repackaging and recognition of used vintage chips: kzread.info/dash/bejne/nWtmtah7f73FnNo.html

More like Grand-Master Ken.

Why not build an adapter that uses a smaller rtc like bq3285 ?

Decap and schematic for the Roland 106 chip on board ceramic proprietary circuit that Roland has no interest in reproducing or helping with? Would be many grateful people. Thanks great content!

Brilliant Idea Sir.

I'm sure it's a bit more of a mundane topic for this channel, but I've always been curious about how prevelant counterfeit ICs are on aliexpress. I feel like every chip I've bought from there has had something fishy about it. Especially the 74HC595s where the TI logo is a picture of the United States lol. Guess they didn't know what Texas was. Still, in my day to day use I wouldn't suspect anything was off about these chips. But I suspect if I characterized the chips more purposefully I would find some anomalies compared to the datasheet.

Merci Marc super interessant, ce semble que le chinoise trouvé le die d'orgine?

@CuriousMarc

3 жыл бұрын

oui. C’etait une vraie.

@dm4728

3 жыл бұрын

Géniale, je chercher une IC obsolète, Reticon SDA1024A, malheureusement le chinoise ne fabriqué même pas de faux 🙁 (Désolé je suis Anglais mais j'aime bien de utilise mon language française des temps en temps)

@CuriousMarc

3 жыл бұрын

@@dm4728 Bravo pour le français!

Can you recommend a microscope for doing work like this?

My oh my - they did NOT think of including a cheap-arse 2.5V Zener diode to protect the chip whenever the battery goes open-circuit? Either penny-pinching in the wrong place, or just plain ignorance.

@CuriousMarc

4 жыл бұрын

I think neither. They probably could not tolerate the Zener leakage.

@andrewallen9993

4 жыл бұрын

@@CuriousMarc And if it was on a maintenance contract your friendly local HP customer engineer would replace it at every PM. If you didn't have a maintenance contract it would cost you an arm and two legs for it to be replaced and serve you right according to Bill and Dave :)

Obviously the Chinese chips were removed from similar devices, and because of that just as fried as the original ones

add a zener over the battery

Not sure why i even watched this. I thought it was about potato chips, but it was about telescopes and stuff

Why are you asking me for? You’re the one that’s supposed to do the research for us so we can learn

Let's take a moment to congratulate the Chinese on their ingenuity. It takes brains to do what they do.

i know purist are going to hate this, but look into fpga, there are some brilliant hdl programmers out there

great videos. Please make compare video of US / USSR chip clones :0)

I saw a video where some guys working in horrible conditions remove chips from boards, and the chips are then repackaged to make them appear new. Could it be you got recycled failed legitimate silicon in new packaging?

@CuriousMarc

4 жыл бұрын

I looked at them closely again, they appear to be, new old stock, genuine chips. If they had been in some previous equipment, then they were cleaned up very well.

13:07 why is one mostly green, while the other one is yellow?

@CuriousMarc

Жыл бұрын

Probably the thickness or composition of the passivation layer on top is different.

Much better to use X-ray when investigating chips. Easier to enlarge the picture too.

The way these Chinese chips ended up in your possession is that someone dropped one of those modules into an e-waste pile and then someone in China desoldered the chip and cleaned it up and put it back on the market. Nowadays, anything sold as "new" or "NOS" from China is actually re-marked old stock, so don't trust it. If this is a common fault, the chips you bought were almost certainly dead too. You'll probably have to figure out how to engineer a modern replacement.

@Beatnik-Manor

4 жыл бұрын

More than likely Dismantled in india and sold on to china

@andrewallen9993

4 жыл бұрын

@@Beatnik-Manor You obviously frequent the same places in Bengaluru as I do when looking for bits for keeping old plant electronics alive :)

Two thoughts: The Chinese ICs may have been pulled off a PCB and made to look new or they were genuine NOS but were improperly handled and died from an ESD.

they dont have to give you a fake chip

It's too bad that it could not be retrofitted with something like an Oki 5832 Clock Calendar IC.

Most likely those Chinese chips came from the recyclers who got bunch of those old HP modules with the dead batteries, so the clock chips were not good in the first place. Those recyclers they will try to pull everything that seems to have value and sell.

@CuriousMarc

3 жыл бұрын

That’s what I feared too, but in a later episode kzread.info/dash/bejne/oqZqqraih9Wznc4.html I built a LED watch chip tester, and they all tested good!

Perhaps a 3-4v zener (or couple of LEDs in series) across the battery so it can never go to 5v again? Surprised the original engineers missed that.

@davebing11

Жыл бұрын

the leakage current is waay too high to use zeners or leds. .

i have a chip and can,t find a listing it is so-8 no numbers mvra lenb please help that all that is on it

What google engineers do in their spare time.

Chinese one wafers bought from TI and they wire bonding in China maybe

Those chips are real. We've been sending our e-trash to China in millions of tons. In one time they noticed that they can do a business of rare chips. So they are desoldering parts, cleaning, straightening legs and even sometimes relabelling. Then selling via AliExpress...

me a chinese: if it works. then dont ask

How does the RTC battery 'going bad' double its voltage? Do two parallel cells somehow become two series cells?

@jg374

4 жыл бұрын

Probably they go open circuit and the charger / power supply is relying on them to pull the voltage down to a safe level for the rest of the circuit.

@davidf2281

4 жыл бұрын

@@jg374 Ah of course, that makes more sense. Thanks.

@MrFathead

4 жыл бұрын

@@jg374 You would expect hp to have done a bit better job to prevent that. It wouldn't have taken much.

@nrdesign1991

4 жыл бұрын

@@MrFathead Just a simple zener diode to be exact.

@davebing11

Жыл бұрын

@@nrdesign1991 cant use a zener in that circuit. leakage current is waay too high. These clock chips typically ran on something like 100nA back then. Maybe as much as a 1 uA

2:23 To be HP that was some really bad design.

@VintageTechFan

4 жыл бұрын

Was quite common. Some portable tube radios had the same problem, the tubes in it were specified for 1.4V heating voltage and there was a single NiCd cell in there, which was recharged from the mains if used at home. If this cell did go bad or was missing, the voltage shot up and blew ALL the filaments. When this was designed, its quite possible that the people who designed it were still very familiar with this arrangement .. it was just 10 years ago that those radios finally got out of favour.

@dtiydr

4 жыл бұрын

@@VintageTechFan Well to see other brands do it wouldn't have been surprised, but HP have the best tech and should address it. Only a few components would have fixed it but they didn't even do that, no matter if it was 40 years ago or not. But who knows, it might back then have been and design thing to destroy it after some time.

Can you somehow build a circuit to effectively disable the battery from the rest of the circuit when the voltage goes over 2.5vDC?

@blitzroehre1807

4 жыл бұрын

Zener diode

Some other video on KZread suggest those chip are recycled, that means they have the same problem as your original chip. A.K.A: they are fried. Some of those chip are just pulled of the board and receive a "beautification" treatment to look like new. but are actually old chip with varying degrees of use and abuse pulled out of they board, sometimes in a very brutal away, package and ship with littler or no consideration to work condition.

@isettech

4 жыл бұрын

There are many contaminates that slowly diffuse into the semiconductor killing it over time. The contamination migrates faster at elevated temperature. It migrates even without power. Many warehoused parts are not in climate controlled conditions. When CPU's went to copper interconnects, it was discovered Copper is one of the contaminates. The process is very specific to copper plate and plane the ILD side of the chip while protecting the semicondictor side from copper contamination. Many of the vintage chips did not have the knowledge of the migration contamination failures until much later. Simple copper pipe used before water quality issues were discovered, resulted in chips with slowly migrating poison to the transistors. Contamination can be from the process with some trace copper contamination to die cutting, to packaging. For more info.. www.smta.org/chapters/files/Philadelphia_SMTA_Philly_Rev2.pdf

like a varta battery.

The battery may have damaged the PCB. Don't destroy the chips lol.

@davebing11

Жыл бұрын

damaged pcb is very easy to notice due to the chemicals in the battery discoloring the pcb

CM PLEASE DO CRT VIDEOS