EEVblog #993 - Mailbag

More mailbag!
More teardowns!

SPOILERS:
Tekbox TBLC08 CISPR16 Line Impedance Stabilization Network (LISN) for the measurement of mains line-conducted interference:

RF Telemetry Transmitter teardown

Telecoms line PCB's from the 1980's and 1990's

Gridseed G-Blade Scrypt cryptocurrency miner

Rogaine video advertisement hardware teardown

Support the EEVblog through Patreon!

EEVblog Amazon Store (Dave gets a cut):

[BlackEpyon]

16:00 Just a note about RS-232, the address is set on the computer. Those switches would be for changing the baud rate, parity, bits, or such, which the host computer would have to match.

[Q_Branch]

I worked as an AXE 10 test plant support engineer and AXE 10 program producer, then later I also ran production for AXE 10 software systems, then became Unix / AXE / Net admin / developer / tester. Loved every moment of it, Ericsson was a great company to work for. Switched over to mechanical engineering now. Great seeing AXE stuff. (It's not pronounced like the wood chopping device... AXE is an Ericsson product code and is just pronounced "A" "X" "E"....)

[giga-chicken]

14:49
Sniffing glue... this actually explains some things, Dave.

[generic_youtubename]

Dave I love ur videos words cannot express how much I appreciate you. You've set my life trajectory towards EE

[UpLateGeek]

"Person unknown from company unknown" ... in Osborne Park, WA. A quick flyover on the Google Maps suggests only a couple of candidates. But you didn't hear it from me!

[tom]

Those old boards would be great, embedded in clear epoxy and used to make a coffee table or work bench top.

[Nuklen]

33:57 why is there writing on the inside, behind the LCD and board? Did they recycle cardboard advertisement for this? At least that's one enviromental thing about it...

[Soundfactory]

Transmitter 17:20 - The coaxial line is shorted and operates as a resonant circuit and is part of the VCO for the PLL-Circuit. To prevent mechanical microphone effects of a simple L / C oscillating circuit - 73 de DL1LAJ

[mikeselectricstuff]

Piggyback packages were often available for mask-ROM MCUs for development. They were very expensive though.

[TheAkashicTraveller]

The 3D printed part is probably because they make them with different sockets on the front and so they only need that specific part for the Australian socket.

[syncmastern]

Sat at Dublin airport, just heard my flight s been delayed.. Dave saves the day with a new video

[cemx]

The Rogaine thing is not intended to be sent to millions of balding guys so that they run to the doctor to get the stuff, that would be cost prohibitive. It is a limited production run to be sent to doctors. There is SO MUCH MONEY in pharma that this makes sense. Also, the NEW COOL thingy curiosity factory kicks in to open and play this - which keeps it in the mind of the doctor when he meets his patients. Perfectly logical!

[snaprollinpitts]

mail bag is always a fun episode of the EEVBOLG thanks

[zaprodk]

Piggyback packages are still around, look into POP (Package on package) on stuff like the Broadcom SOC on the Raspberry Pi etc. :) - the digital advertisement is using an AllWinner ARM926-EJS E200-CPU.

[Willam_J]

Am I the only one who thinks that the person who sent the Rogaine video display should have put a 'Rick Roll' video on it? :-D

[vylbird]

I've fixed those miners before. The board has two power supplies on it:
- A dinky 3.3V linear reg, supplied off USB, that feeds the ARM micro which serves as control and PC interface.
- A buck converter that supplies 2.5V for the mining chips, fed off the DC jack. It's a very obscure but high-efficiency synchronous buck converter. Looks like that's the section that failed.

I have one where the ARM chip failed. I could replace it, but without a firmware image that wouldn't be enough to get it working. Although, if I had the chip off of yours... yes, that would probably let me get mine going. I'll send you a cool home-built PWM solar charge controller in return, if you want.

Also, you're off about the heatsinks. It's not lots of litte ones: It's designed for a single huge heatsink that serves all the ASICs together.

[jaa]

24:12 120 ohm termination / line match to 50 ohm? I reckon this was part of the telstra - Optus STP (signal transfer point) maybe?

[aleestro]

Hey Dave, my dad was a dermatologist and he'd receive all types of promotional materials (bribery) from pharma/skincare companies- free samples of sunscreens and lotions, literature detailing various products, other branded doodads- to convince him to use or recommend their product to his patients.

So the Rogaine ad is most likely something mailed or handed out at a trade show to a doctor or specialist- only meant for their eyes, so it's still wasteful, but less so than if it were in a major circulation magazine.

Seems like a pretty cunning advertising strategy actually. Convince a single person trusted by dozens, hundreds, thousands of people to promote your product rather than spend time and money reaching and convincing every individual to trust your company and then buy your product!

In fact, I signed up for Tron Club because you were impressed by it and recommended it in one of your mailbags :p

PS- I only recently came across your channel, and although I know next to nothing about electrical engineering, or maybe because of that fact, I absolutely love your work and I feel like I'm really learning a lot!

Cheers!

[avidrandomer]

The SOC is not a powerpc part but actually an Allwinner E200 ARM9 part.

[Arnthorg]

26:00 My guess is that there had been attempts to overclock and overvoltage that miner. The miners are basically paperweights by that point so I guess it doesn't hurt to experiment.