So you bring home a shiny new gadget. You plug it into your network, turn it on, and it does… well, whatever it wants. Hopefully, it does what you expect and no more, but there is no guarantee: it could be sending your network traffic to the NSA, MI5 or just the highest bidder. [Jelmer] decided to find out what a new IP camera did, and how easy it was to find out by taking a good poke around inside.
In his write-up of this teardown, he describes how he used Wireshark to see who the camera was talking to over the Interwebs, and how he was able to get root access to the device itself (spoilers: the root password was 1234546). He did this by using the serial interface of the Ralink RT3050 that is the brains of the camera to get in, which provided a nice console when he asked politely. A bit of poking around found the password file, which was all too easily decrypted with John the ripper.
This is basic stuff, but if you’ve never opened up an embedded Linux device and gotten root on it, you absolutely should. And now you’ve got a nicely written lesson in how to do it. Go poke around inside the things you own!
[dmalhar] was digging around in his bins for motors and found one with missing brushes. Being resourceful (and not able to find another motor), he managed to tear apart a SATA cable and form the pins into brushes with just the right amount of spring. Yes, this looks like a cheap motor, but in the moment of necessity availability wins, and this hack is truly commendable. If he had used a paperclip, MacGyver would have been proud, but the SATA cable pins make us proud.
Normally the brushes of DC motors are made with a graphite or some other material which provides a small amount of resistance so that when the motor is spinning the brushes will provide a gradual shift of current from one commutator to the next. Also, the softness of the carbon makes the brush wear down instead of the commutator, and in large motors the brushes are replaceable. In cheap motors the engineers design the brush material around the expected lifetime of the product. In [dmalhar’s] case, the motor just got its lifetime extended by a while.
Have you ever fancied a gadget but been put off by what seems like an excessive price? [leadacid44] did just that back in 2009, in his case the gadget in question was a Sony Dream Machine ICF-CL75iP. It’s an alarm clock radio, albeit a very fancy one featuring an iPod dock, SD card slot, and an electronic photo frame. Back then it was just too expensive, but in 2016 [leadacid44] spotted one on an auction site for pennies, and so snapped it up.
Of course, with something cheap there is so often a catch. In the case of this Dream Machine, it would not keep time — something pretty important in a clock. But rather than throw it on the “Hack later” pile, [leadacid44] decided to investigate, and turned up a surprising culprit. The glue Sony had used to secure the timing crystal in 2009 had become conductive with age, causing the oscillator to stop oscillating. A simple fix involving a bit of glue removal and a touch of resoldering, and the clock was back with us.
This was a very simple repair when the problem was diagnosed, but it tells us something about electronic product design, and about quality control. Sony have spent a very long time building a reputation for quality manufacture, and it is likely the Dream Machine was built with their full attention to detail. It is highly unlikely that the Sony engineers chose their crystal glue in the knowledge it would break down, after all the company is likely to make far more money selling a new TV or phone to a satisfied alarm clock owner than it is by selling them a new alarm clock. Instead it tells us that even Sony with a legendary attention to quality control can be caught out by unexpected component failures, and that as engineers we should always expect the unexpected.
So [leadacid44] has a new alarm clock, and presumably now always wakes up on time. It’s interesting to look at the Dream Machine from another perspective, to compare what was hot in 2009 with what you might see now. The Apple Dock connector for instance, or the full-size SD card. Both of which are now becoming historical curiosities, even though this device is not much more than six years old.
Over the years we’ve featured a lot of clocks, and even the odd clock radio. But this isn’t really about clock radios, and with that out of the way we’ve certainly featured a few Sony hacks.
[quarterturn] had an old Apple Powerbook 520c sitting around in his junk bin. For the time, it was a great computer but in a more modern light, it could use an upgrade. It can’t run BSD, either: you need an FPU for that, and the 520 used the low-cost, FPU-less version of the 68040 as its main processor. You can buy versions of the 68040 with FPUs direct from China, which means turning this old Powerbook into a BSD powerhouse is just a matter of desoldering and upgrading the CPU. That’s exactly what [quarterturn] did, with an unexpected but not surprising setback.
The motherboard for the Powerbook 500 series was cleverly designed, with daughter cards for the CPU itself and RAM upgrades. After pulling the CPU daughter card from his laptop, [quarterturn] faced his nemesis: a 180-pin QFP 68LC040. Removing the CPU was handled relatively easily by liberal application of ChipQuik. A few quick hits with solder braid and some flux cleaned everything up, and the daughter card was ready for a new CPU.
The new FPU-equipped CPU arrived from China, and after some very careful inspection, soldering, and testing, [quarterturn] had a new CPU for his Powerbook. Once the Powerbook was back up and running, there was a slight problem. The chip was fake. Even though the new CPU was labeled as a 68040, it didn’t have an FPU. People will counterfeit anything, including processors from the early 90s. This means no FPU, no BSD, and [quarterturn] is effectively back to square one.
That doesn’t mean this exercise was a complete loss. [quarterturn] did learn a few things from this experience. You can, in fact, desolder a dense QFP with ChipQuik, and you can solder the same chip with a regular soldering iron. Networking across 20 years of the Macintosh operating system is a mess, and caveat emptor doesn’t translate into Mandarin.
Cheap benchtop power supplies are generally regarded as pieces of junk around these parts. They can measure well enough under perfect conditions, but when you use them a little bit, they fall over. There’s proof of this in hundreds of EEVblog posts, Amazon reviews, and stories from people who have actually owned these el-cheapo power supplies.
One of the guys who has had a difficult time with these power supplies is [Richard]. He picked up a MPJA 9616PS (or Circuit Specialists CSI3003SM) for a song. It quickly broke, and that means it’s time for a repair video. [Richard] is doing this one better – he has the 3A power supply, that sells for $55. With a stupidly simple modification, he upgraded this power supply to the 5A model that usually sells for $100.
The problem with [Richard]’s broken power supply were voltage and current adjustments knobs. This cheap power supply didn’t use rotary encoders – voltage and current were controlled by a pair of 1k and 10k pots. Replacing these parts cost about $5, and [Richard]’s power supply was back up on its feet.
After poking around inside this power supply, [Richard] noticed two blue trim pots. These trim pots were cranked all the way to the left, and by cranking them all the way to the right, the power supply could output 5 Amps. Yes, the 3A version of this power supply was almost identical to the 5A version, with the only difference being the price. It’s a good repair to a somewhat crappy but serviceable supply, but a great mod that puts a beefier power supply on [Richard]’s desk.
Continue reading “Repairing and Improving Cheap Bench Power Supplies”
Precision standards are the pinnacle of test and measuring instrumentation. Well engineered, sure, but also beautifully built and a feast to look at, no matter how old they are. [Shahriar] at “The Signal Path” often gives us the skinny on such equipment. In the latest episode, we get a look inside a Valhalla 2701C Programmable Precision DC Voltage Standard.
Even by 1990 standards, it is a fairly basic instrument, capable of producing just DC Voltages from 100nV up to 1200V. But it is a reference standard, so the output is highly stable, accurate and precise. He snagged it from eBay on the cheap but transport seemed to have caused some damage. It would switch on and relays would click when he pressed buttons, but the 7-segment LED display was blank. Luckily, opening the top cover fixes that problem – just a loose connection between the front display and the main board. Examination also shows that adding a 120mA DC current range would require adding additional components on the main board so his hope of doing a quick firmware upgrade is short lived.
[Shahriar] takes the opportunity to walk us through the various sections of the well built unit. It’s apparently seen some repairs during it’s life. A few capacitors look changed, and a relay housing has seen damage from a soldering iron. The digital section is mainly the 6800 micro controller, an EPROM and a NVRAM, and it generates the PWM signals needed for producing the output voltages. A highly precise reference signal is essential for such equipment, and this one uses the LM299 with a “custom” suffix meaning it was specially screened and binned. He does a quick calibration run, but it’s obviously rushed and doesn’t produce stable results. But that could also be due to the low quality cables he used, or a number of other factors. Calibrating such equipment is a job demanding both time and patience.
While this may not knock your socks off. For that, check out this post where [Shahriar] does a tear down of the one million dollar Labmaster 10-100zi Oscilloscope, or this other one where he plays around with a half a million dollar oscilloscope you’ll probably never use, much less own.
Continue reading “Repair and Calibration of Valhalla Programmable Precision Standard”
[dyril] over on the EEVblog has a broken LED TV. It’s a fairly standard Samsung TV from 2012 that unfortunately had a little bit of corrosion on the flexible circuit boards thanks to excessive humidity. One day, [dyril] turned on his TV and found about one-third of the screen was glitchy. After [dyril] took the TV apart, an extremely strange fix was found: shining a light on the corroded flexible circuit board fixed the TV.
The fix, obviously, was to solder a USB light to a power rail on the TV and hot glue the light so it shines on the offending circuit. Solving a problem is one thing, though, understanding why you’ve solved the problem is another thing entirely. [dyril] has no idea why this fix works, and it’s doubtful anyone can give him a complete explanation.
The TV is fixed, and although you can’t argue with results, there is a burning question: how on Earth does shining a light on a broken circuit board fix a TV? Speculation on the EEVblog thread seems to have settled on something similar to the photonic reset of the Raspberry Pi 2. In the Raspberry Pi 2, a small chip scale package (CSP) used in the power supply section would fail when exposed to light. This reset the Pi, and turned out to be a very educational introduction to photons and energy levels for thousands of people with a Pi.
The best guess from the EEVblog is that a chip on the offending board handles a differential signal going to the flex circuit. This chip is sensitive to light, and shutting it down with photons allows the other half of the differential signal to take over. It’s a hand-wavy explanation, but then again this is a very, very weird problem.
You can check out [dyril]’s video demonstration of the problem and solution below. Thanks [Rasz] for sending this one in.
Continue reading “Fixing Broken Monitors By Shining A Flashlight”