Day: April 6, 2024

Inside A Hisense TV Repair Attempt

April 6, 2024 by 18 Comments

Many of us misspent our youth fixing televisions. But fixing a 1970s TV is a lot different than today — the parts were big and tubes were made to be replaced. Have you torn into a big flat screen lately? It is a different world, as [The Fixologist] shows us in the video below.

The TV in question was rescued from a neighbor who was about to throw it away. If you are like us, you’ll watch the first few minutes and see it powers up, but the screen is very dark. Back light problem, right? No problem. But it turned out to be more than we thought.

Honestly, we assumed it might be the power supply, and we would have put a power supply on the LED leads to test that first. That would have been smart because taking the panel off to reveal the LEDs was very difficult! There were two bad LEDs, though, so in the end you’d have had to do it anyway.

We were disappointed that after fixing the LED, he cracked the LCD panel during the reinstallation. So, in the end, this was more of a teardown video and not a repair video. He seemed to think a lot of the tape in the unit was to thwart repairs. That could be, but we wondered if it made manufacturing the TV easier which, after all, is mostly what they care about.

This isn’t the first time we’ve heard people tearing into a TV and wondering if the factory was against them. We’ve considered it, but we are pretty sure it isn’t the case.

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How To Properly Patch Your Iowa-Class Battleship

April 6, 2024 by 28 Comments

There’s a saying among recreational mariners that the word “boat” is actually an acronym for “bring out another thousand”, as it seems you can’t operate one for long without committing to expensive maintenance and repairs. But this axiom isn’t limited to just civilian pleasure craft, it also holds true for large and complex vessels — although the bill generally has a few more zeros at the end.

Consider the USS New Jersey (BB-62), an Iowa-class battleship that first served in the Second World War and is now operated as a museum ship. Its recent dry docking for routine repair work has been extensively documented on YouTube by curator [Ryan Szimanski], and in the latest video, he covers one of the most important tasks crews have to attend to while the ship is out of the water: inspecting and repairing the hundreds of patches that line the hull.

These patches aren’t to repair damage, but instead cover up the various water inlets and outlets required by onboard systems. When New Jersey was finally decommissioned in 1991, it was hauled out of the water and plates were welded over all of these access points to prevent any potential leaks. But as the Navy wanted to preserve the ship so it could potentially be reactivated if necessary, care was taken to make the process reversible.

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DIY 6 GHZ Pulse Compression Radar

April 6, 2024 by 10 Comments

Conceptually, radar is pretty simple: send out a radio wave and time how long it takes to get back via an echo. However, in practice, there are a number of trade-offs to consider. For example, producing a long pulse has more energy and range, but limits how close you can see and also the system’s ability to resolve objects that are close to each other. Pulse compression uses a long transmission that varies in frequency. Reflected waves can be reconstituted to act more like a short pulse since there is information about the exact timing of the reflected energy. [Henrik] didn’t want to make things too easy, so he decided to build a pulse compression radar that operates at 6 GHz.

In all fairness, [Henrik] is no neophyte when it comes to radar. He’s made several more traditional devices using a continuous wave architecture. However, this type of radar is only found in a few restricted applications due to its inherent limitations. The new system can operate in a continuous wave mode, but can also code pulses using arbitrary waveforms.

Some design choices were made to save money. For example, the transmitter and receiver have limited filtering. In addition, the receiver isn’t a superheterodyne but more of a direct conversion receiver. The signal processing is made much easier by using a Zynq FPGA with a dual-core ARM CPU onboard. These were expensive from normal sources but could be had from online Chinese vendors for about $17. The system could boot Linux, although that’s future work, according to [Henrik].

At 6 GHz, everything is harder. Routing the PCB for DDR3 RAM is also tricky, but you can read how it was done in the original post. To say we were impressed with the work would be an understatement. We bet you will be too.

Radar has come a long way since World War II and is in more places than you might guess. We hate to admit it, but we’d be more likely to buy a ready-made radar module if we needed it.

Kid’s Ride Gets Boosted Battery, ESP32 Control

April 6, 2024 by 15 Comments

That irresistible urge to rescue an interesting piece of hardware from the trash is something that pretty much every Hackaday reader will have felt at one time or another. Sometimes it’s something that you could put to work immediately, like an old computer or some scrap piece of material that’s just the right size. But other times, you find something on the side of the road that ends up being the impetus for a whole new project.

For [David Bertet], finding a beat up kid’s Jeep Wrangler on the curb was the first step towards a journey that ends with PowerJeep: an open source project that we wager could end up saving similar vehicles from the landfill. The basic idea is simple enough — strip out the vehicle’s original 12 volt power supply and replace it with 18 V provided by easily swappable tool batteries. But as is often the case, it’s the details and the documentation that sets this project apart.

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IRC Client On Bare Metal

April 6, 2024 by 14 Comments

In the beginning, there was the BIOS, and it was good. A PC’s BIOS knows how to set up the different hardware devices, grab a fixed part of a hard drive, load it, and run it. That’s all you need. While it might be all you need, it isn’t everything people want, so a consortium developed UEFI, which can do all the things a normal BIOS can’t. Among other things, UEFI can load code for the operating system over the network instead of from the hard drive.

In true hacker fashion, [Phillip Tennen] thought, “Does it have to be an operating system?” The answer, of course, is no. It could be an IRC client. He chose Rust to implement everything. While UEFI does provide a network stack, it isn’t very easy to use, apparently. It also provides support for a mouse. [Phillip] ported his GUI toolkit library over, and then the rest is just building an IRC client.

The client isn’t the easiest to use because, after all, this is a lark. Why would you want to do this? On the other hand, we can think of reasons we might want to take control of a UEFI motherboard and use it for something. If you want to do that, this project is a great template to jump-start your endeavors.

We’ve looked at the UEFI system a few times. Or, you can use it to play DOOM.

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Understand Your Tools: Finger Exercises

April 6, 2024 by 12 Comments

A dip meter is basically a coil of wire that, when you excite it, you can use to tell if something inside that coil is resonating along. This lets you measure unknown radio circuits to figure out their resonant frequency, for instance. This week, we featured a clever way to make a dip meter with a nanoVNA, which is an odd hack simply because a dip meter used to be a common spare-parts DIY device, while a vector network analyzer used to cost more than a house.

Times have changed, and for the better. Nowadays, any radio amateur can pick up a VNA for less than the cost of all but the cheesiest of walkie talkies, putting formerly exotic test equipment in the hands of untrained mortals. But what good is a fancy-pants tool if you don’t know how to use it? Our own Jenny List faced exactly this problem when she picked up a nanoVNA, and her first steps are worth following along with if you find yourself in her shoes.

All of this reminded me of an excellent series by Mike Szczys, “Scope Noob”, where he chronicled his forays into learning how to use an oscilloscope by running all of the basic functions by working through a bunch of test measurements that he already knew the answer to.

It strikes me that we could use something like this for nearly every piece of measuring equipment. Something more than just an instruction manual that walks you through what all the dials do. Something that takes you through a bunch of example projects and shows you how to use the tool in question through a handful of projects. Because these days, access to many formerly exotic pieces of measuring gear has enabled many folks to have gear they never would have had before – and all that’s missing is knowing how to drive them.

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Voyager 1 Issue Tracked Down To Defective Memory Chip

April 6, 2024 by 52 Comments

After more than forty-six years all of us are likely to feel the wear of time, and Voyager 1 is no different. Following months of harrowing troubleshooting as the far-flung spacecraft stopped returning sensible data, NASA engineers now feel confident that they have tracked down the cause for the problem: a single defective memory chip. Why this particular chip failed is unknown, but possibilities range from wear and tear to an energetic particle hitting it and disrupting its operation.

We’ve covered the Voyager 1 troubleshooting saga so far, with the initial garbled responses attributed to a range of systems, but narrowed down to the Flight Data Subsystem (FDS), which prepares data for transmission by the telemetry modulation unit (TMU). Based on a recent ‘poke’ command that returned a memory dump engineers concluded that the approximately 3% of corrupted data fit with this one memory chip, opening the possibility of a workaround.

Recently NASA engineers have also been working on patching up the firmware in both Voyager spacecraft, against the background of the dwindling energy produced by the radioisotope generators that have kept both spacecraft powered and warm, even in the cold, dark depths of Deep Space far beyond the light of our Sun.