IMSAI Guy Looks at Counterfeit Chips

Like some of the commenters, I had been scratching my head wondering why someone would go to all the trouble of counterfeiting electronic parts.  It just didn't seem to make economic sense.  Perhaps they were just marketing factory rejects?   But no,  IMSAI Guy shows in the video above that it is a lot more insidious.  It turns out that this kind of crime DOES make economic sense (see comments).  So be careful out there. 

Here is another one IMSAI Guy did yesterday, looking at other faked chips: 

Thank you IMSAI Guy! 

Sunburst and Luminary -- A Poem about Transistors and ICs

 

Sunburst and Luminary by Don Eyles has a lot of the kind of color that helps the reader understand what was going on technologically during the 1960s.  For example, there is this poem about integrated circuits (you don't get to use "poem" and "integrated circuits" in the same sentence very often): 

The transistor's a marvelous invention

Replaced the tube convention

        Found its niche

        To amplify or switch

Whatever the designer's intention. 

But the breakthrough was the IC

Integrated monolithically

        It became pivotal

        As computers went digital 

With increasing complexity. 

Eyles tells us that this poem was written by hardware designer Jayne Partridge, and appears in Eldon Hall's write-up of the Apollo Guidance Computer and the decision to use ICs in it: 

https://www.amazon.com/Journey-Moon-Guidance-Computer-1996-09-03/dp/B01F9FSN7C  

Part 2: CuriousMarc Fixes an All-Discrete Counter -- "Like an IC, but in discrete form."

Marc nicely sums up this project with this line:  "It's an IC but in discrete form!"  On the same theme, he later says, "Who needs a logic analyzer when you can do a visual debug with neon bulbs?" 

Very cool.  Lots of troubleshooting and repair lessons in this video: 

-- Again we see the benefits of paper manuals.  (Todd K7TFC commented astutely on this under yesterday's post.)

-- 2N2222s to the rescue.  

-- A surprisingly large number of bad transistors (6?) found.  Why did they go bad? 

-- Marc repeatedly says, "Let me poke around."  Poking around is often important.  Mark fixes the reset line after poking around.  He is not sure HOW he has fixed it, but he has... by poking around.  Sometimes this happens.  Thank God for small favors. 

-- Marc has some fancy HP board extenders.  I am jealous.  

-- He also has a cool de-soldering tool.  More jealousy.  Want one. 

-- Marc's understanding of how the HP engineers had to put one of the flip-flops "on the edge of stability," and how his 'scope probe was capable of disturbing this stability. 

-- Remember that those Nixies are TUBES with enough voltage on them to really zap you.  So be careful in there.  This is an especially dangerous mix of transistor tech and tube tech.  With transistors you can work on them with the rig fired up.  With tubes, well, you have to be careful.

Part III tomorrow. 

CuriousMarc Repairs an old DISCRETE COMPONENT HP Frequency Counter

I really liked this repair video from CuriousMarc (aka AJ6JV).  This counter pre-dates the use of integrated circuits -- it is all discrete transistors.  Near the end, Marc mentions how this made this repair "like debugging a big integrated circuit, but with access to each transistor -- this made it quite satisfying."  I hear ya Marc -- with big ICs maybe all you would get to do would be to swap out a single IC.  There would not be much of a challenge there.  

With the older, discrete circuitry you get a good view of how Marc troubleshoots -- how he finds the precise points where the device is failing.  Note his use of the old HP paper manuals. I know this is an old guy thing, but I think the paper manuals (as opposed to the online versions)  just make the process easier.  Note too that Marc at one point had to go back to microfiche. 

The transistor tester Mark used was very cool. 

The whole physical structure of the HP device is very similar to my NYC HP8640B.  Thanks again Steve Silverman and Dave Bamford. 

I will look at Parts II and III of this series soon.  

A Homebrew LM386 -- Does Anyone Want to Build It? Help Save Us All from the Indignity of ICs!

 

I recently commented that I was building a discrete LM386 for a Direct Conversion receiver.  I think I was exaggerating my project.  In fact I just built a very ordinary push-pull amplifier using a 2N3904 and a 2N3906 as a complementary pair AF amplifier.  This is part of an LM386, but there is much more inside that little chip.  Dave went much further.  His schematic is above.  

Here is link to a higher definition image: 

http://soldersmoke.com/homebrewLM386.jpg

 

Dave writes: 

Hello Bill -

Please find enclosed the LT spice circuit for the small audio amp that I developed.  I have included numerous notes on the schematic as to component function, suggested values to tweak, etc. 

My intention was to come up with a relatively low parts-count design while adhering to the classic three-stage topology [diff pair / voltage amp / voltage follower] that has been used as the basis for so many audio power amplifiers for decades.  I'm sure some of the parts could be eliminated at the risk of possible stability issues, but a lot of that also depends on proper layout, length of speaker leads, speaker load impedance, etc.

In any case I thought it would be great if someone wanted to build up this design to see if it works in real life or whether any serious mods are needed to get it to behave (I have no illusion that the spice models are entirely accurate, nor is my analysis thorough).

It should be capable of at least 500mW into an 8 ohm load at 9VDC supply, and over a watt at 12VDC.  It should handle a 4 ohm load although at reduced voltage swing on the output, and with increased output transistor heat dissipation requirements. 

The output stage is a complimentary compound ("sziklai") pair which should, in theory, maximize voltage swing from a low supply voltage (as compared to the more traditional complimentary Darlington configuration. 

The bias current is set by a fixed pair of resistors and could be quite different from the simulated value, so I would be careful on initial power-up to monitor the quiescent current draw.  I would guess it need not be more than a few mA or so, and definitely less than 40mA or so.  This can be made adjustable if desired.  

Regards,

Dave

-----------------

So, does anyone out there want to give this a try?   You could be helping to save generations of homebrewers from the indignity of using an integrated circuit! 

Would this Really Be Homebrew?

 

Hack-A-Day has an interesting post about an FM Broadcast radio project.  I took a look.  The Github page has the schematics for the hardware.  For me, the thing is, there is just not a lot there.  It is a bunch of chips.  The FM Tuner IC is the heart of the project.  With that one you have to dig down to see that it is a digital processing chip:

https://www.lcsc.com/product-detail/RF-Transceiver-ICs_RDA-Microelectronics-RDA5807MP_C167245.html

All of the action -- all of the magic of radio -- is locked inside those little SMD chips.  I suppose if you were skilled enough to write the software or to significantly modify it,  you'd get closer to the experience of homebrew radio,  but very few of us have those kinds of skills -- we just download the software, then struggle to get it into the chips. 

And sure, you could struggle to solder those chips to a PC board, but really, why bother when 99% of the components are already inside the chips?  You should just buy a board with the chips on them and with the software already loaded.  There you have it:  the store-bought appliance is really, really close to the supposedly homebrew receiver. 

But hey, to each his own.  This is a hobby and it is all for fun.  I just think I have more fun with old-style, analog, discrete component HDRs.  YMMV.     

My Kind of Chip: A Homebrew Discrete 555 Timer Built on Wooden Boards (video)

This is really beautiful. Radraksha Vegad (Pargrahi) from India built a discrete component version of the venerable 555 timer chip.  He built it on wooden blocks.  This leads to the kind of understanding that even Jean Shepherd would have admired.  No longer is the 555 a little mysterious black box.  No, Pargrahi shows us how it works.   

 I know we could do something similar with the NE602 or the LM386.  But probably not with an Arduino microcontroller or an Si5351.  And that says something about understanding and complexity. 

Thanks Radraksha.  And thanks to Hack-A-Day for alerting us to this: https://hackaday.com/2021/12/20/all-hail-your-new-giant-555-timer-overlord/#more-512230 

Sam KD2ENL's Homebrew Integrated Circuit Chips

Sam Zeloof KD2ENL does some really inspirational work on the homebrewing of IC chips. We first posted about this back in 2018, when Sam was 17: 

https://soldersmoke.blogspot.com/2018/05/youngest-homebrew-hero-17-year-old-sam.html

Sam has some very impressive gear  -- I found myself wondering if that could really be a home lab. But it is.  It is apparently in his garage in New Jersey.  Hack-A-Day reports that Sam got a lot of the gear on e-bay.  And they note that living near Princeton University (great dumpsters!) also helped.  Here is some background on Sam's workshop: 

https://hackaday.com/2018/11/19/of-roach-killer-and-rust-remover-sam-zeloofs-garage-made-chips/

and

https://hackaday.com/2017/02/25/the-fab-lab-next-door-diy-semiconductors/

Sam and his brother Adam KD2MRG are students at Carnegie Mellon University in Pittsburgh. 

Thanks to Hack-A-Day for alerting us to this: 

https://hackaday.com/2021/08/14/the-zeloof-z2-intergrated-circuit-has-100-transistors/

Repairing My Maplin Audio Waveform Generator

I picked this generator at the Kempton Park rally in London many years ago.  I use it quite a bit, not only for circuit testing but also as an easy way to get my homebrew BITX rigs to send a signal so that I can adjust my antenna.  I just plug this thing into the mic jack, crank in a small amount of 1 kHz audio, and I am ready to minimize SWR. 

It never gave me any real problems until last week.  I opened it up and examined the circuitry for the first time.  Lots of mystery chips in there. Fortunately they are all socketed.  Thank you Maplin. 

Even without really knowing how each of the ICs work, it was easy to troubleshoot. See the schematic in the article that begins on page 21 in this .pdf: 

https://worldradiohistory.com/UK/Mapelin/Maplin-Projects-Book-48.pdf

My Rigol scope showed a good signal going into and coming out of IC8, the LF351 op-amp.  From there the signal goes to IC5 a 4066BE.  But nothing was coming out of IC5.  Thus IC5 was my lead suspect.  I put in a quick order to Digikey.  A couple of days and a few bucks later the chips (as always, I ordered several) were on my doorstep.  Within a few minutes IC5 was replaced and the generator was as good as new. 

One annoying problem with this generator is that it has no automatic shut-off circuitry.  So if I forget to turn it off, I soon have to buy two 9V batteries. Tony G4WIF suggested a simple timer circuit.  I may do that soon.  Or, given that we are already on the IC dark side with this project, there is this: https://www.youtube.com/watch?v=C4C2H_3BU3o&feature=youtu.be 

I recently find myself replacing a lot of chips in various rigs and devices in my shack.  It seems that chips go bad more frequently than discrete transistors or even tubes.  But maybe I'm just using older gear with older, more fragile chips.   What do you folks think? 

Great Video on PC Board Techniques, with a Focus on Surface Mount

Wow, lots of wisdom in this video from Leo Fernekes.  Great hints and kinks on prototyping with copper clad boards. I need a Dremel just so that I can make Leo's board cutter.  And I can see that I need some of that liquid flux and isopropyl alcohol. Surf boards and headers! Who knew?  Teflon coating for the wires -- gotta get it. Glad to see that Leo is also a fan of copper tape.

His emphasis on the importance of stage-by-stage construction and testing is right on the mark.  

My only disagreement with Leo is about his use of steel wool.  I've found that steel wool will inevitably cause little tiny "Murphy Whiskers" to float around your workbench. They will eventually settle onto the most inconvenient and damaging place on your board.  So I have banished steel wool from my workshop.  Those green, non-metallic Scotch Brite pads work just as well and don't cause shorts. 

Three cheers for Leo. He is based in Thailand.  He has an interesting background and some really amazing projects and insights:  

http://www.luminati.aero/leofernekes

http://www.fernekes.com/blog/

https://www.youtube.com/channel/UCe1bjEcBichpiAMhExh0NiQ/videos

Thanks to Tore LB4RG for alerting us to Leo's video.  

An Understandable Chip: The LM386

Over the years I have made my distaste for integrated circuits very clear.  I've presented them as mysterious little black boxes that don't really belong in our homebrew rigs,  rigs that we are building, after all,  because we want to avoid the use of MYSTERIOUS BLACK BOXES.  

So, I don't use voltage regulator chips -- I use Zener diodes.   I prefer analog LC oscillators to AD9850s or Si5351s.  And I have repeatedly built discrete component audio amplifiers when most normal people just put an IC AF amplifier in the circuit. 

When I built the Q-31 Shortwave AM receiver, I kind of ran out of gas at the end.  I wanted to get the receiver going and I didn't want to build yet another discrete AF amp.  So I used an LM386.  

I rationalized this deviation from cherished values by noting that the discrete AF amplifier circuitry that I was using was remarkably similar to what exists inside the LM386.  So that little chip is just as understandable as my discrete component creations.  It wasn't REALLY a mysterious black box... 

Around this time I found a web site that made me feel mush better about all this.  It explains very nicely how the little LM386 does such a great job.  It really packs a lot of amplification into a very small package.   Here is the web site: 

https://www.electrosmash.com/lm386-analysis

Shortly after my transgression,  Jenny List over at Hack-A-Day posted a nice piece looking at the inner workings of Op-Amps.  Who knows, I may seen be using 741 chips too! 

Here is the Hack-A-Day piece: 

https://hackaday.com/2020/05/09/an-op-amp-from-the-ground-up/

Youngest Homebrew Hero: 17 year-old Sam Zeelof Makes His Own Integrated Circuits

Seventeen year-old Sam Zeelof, KD2ENL, is making his own integrated circuits in his garage. 

Wow.  This makes me think about another seventeen year-old -- the fellow who appears on pages 63-64 of Cliff DeSoto's "200 Meters and Down." (I have the story on page 81 of "SolderSmoke -- Global Adventures in Wireless Electronics.")   In the early days of radio that kid amazed us by making his own vacuum tubes.  Sam Zeelof is clearly following in that tradition. 

No "mysterious black boxes" for Sam!  No "appliance chips" for him!  FB OM.  

This is really amazing.  Here are the links: 

https://spectrum.ieee.org/semiconductors/devices/the-high-school-student-whos-building-his-own-integrated-circuits

http://sam.zeloof.xyz/category/semiconductor/

One of Sam's chips

Thanks to Bruce KC1FSZ for alerting us to this amazing work. 

AMAZING 1999 Video on the Invention of the Transistor at "Hell's Bells Laboratory"

Thanks to Armand WA1UQO for alerting me to this.  I really liked the book -- "Crystal Fire" -- that this 1999 video is loosely based on. I'm also a fan of the narrator,  Ira Flatow, whose melodious voice is heard each week on NPR's excellent "Science Friday" radio show. 

A few observations and thoughts on the video: 

-- I liked the irreverant Calypso song "Hell's Bells Laboratory."  It looks like those folks had a lot of fun.  And wow, Shockly's secretary was named Betty Sparks.  TRGHS. 

-- I have the same big Variac on my bench.  And I have one of those "third hand" devices.  

-- I'd like to build my own replica of the point contact device with the triangular piece of lucite and the gold foil. 

-- While Shockley seems to be the real bad guy in this story (he seems to have all the bad characteristics of David Sarnoff,  Lee DeForest, and Steve Jobs),  I liked the his use of "physical intuition" to understand devices and the problems they were meant to solve.  

-- The image of the two Japanese founders of Sony working in the late 1940's in a bombed out department store was very powerful.   

-- Although I came on the scence a bit later, I WAS one of those kids who used a transistor radio and an earphone to surreptitiously listen to rock-and-roll music. 

-- "More transistors are made each year than raindrops fall on California."  Hmmm.... 

More info here:  http://www.pbs.org/transistor/
Extra interviews:  http://www.pbs.org/transistor/tv/index.html

Great Hackaday Article on the Venerable LM386

I'm not crazy about chips, but I've come to like the LM386.  It is not really a little black mystery box -- as the article points out, the internal circuitry is simple and completely understandable.  So you shouldn't feel any appliance-op angst when you use one of these. 

http://hackaday.com/2016/12/07/you-can-have-my-lm386s-when-you-pry-them-from-my-cold-dead-hands/