#fixed resistor

[addohaislam2000]

Voltage dividers, chip resistors, surface mount resistors, fixed resistors

TNPW Series 0402 0.1 W 2 kOhm ±0.1 % ±25 ppm/K Thin Film Flat Chip Resistor

[nick-momrik]

Repairing a Ryobi P117 Intelliport Charger

Last week while cutting some walnut with my Ryobi track saw, it kept stalling on me. Turns out the battery was nearly dead because the charger stopped working and the status LEDs weren’t lighting up at all when plugged in. I opened up the charger and didn’t see burn marks or swollen capacitors anywhere. Then I found a video on YouTube and sure enough, the resistor at R71 was wide open, reading…

[edrmilotn]

https://www.futureelectronics.com/p/passives--resistors--fixed-resistors/wsl25127l000fea-vishay-9135757

Vishay, WSL25127L000FEA, Resistors, Fixed Resistors

WSL Series 2512 1 W 0.007 Ohm ±1% ±75 ppm/°C SMT Power Metal Strip® Resistor

[jstin2iells]

https://www.futureelectronics.com/p/passives--resistors--fixed-resistors/wsl25127l000fea18-vishay-5010564

What is a fixed resistor, programmable resistors, High power resistor

WSL Series 2512 1 W 0.007 Ohm ±1% ±75 ppm/°C SMT Power Metal Strip® Resistor

[cadd2liva]

https://www.futureelectronics.com/p/passives--resistors--fixed-resistors/wsl25127l000fea-vishay-9135757

Chip resistors, what is a resistor, trimmer resistors, high power resistor

WSL Series 2512 1 W 0.007 Ohm ±1% ±75 ppm/°C SMT Power Metal Strip® Resistor

[vaiseshika]

Decade Resistance Boxes Exporter In India - Vaiseshika

Unlocking Precision: Vaiseshika, the leading Decade Resistance Boxes exporter in India, revolutionizes electronic testing. Over the past decade, Vaiseshika has consistently delivered state-of-the-art resistance boxes, catering to diverse industries with unparalleled precision. As a trusted name in the market, their products boast superior quality and reliability. Engineers and technicians across India rely on Vaiseshika's Decade Resistance Boxes for accurate measurements in testing circuits and electronic components. With a commitment to excellence, Vaiseshika continues to shape the future of electronic testing, solidifying its position as the go-to exporter of precision instruments in the country.

[ardl]

i take it back soldering smds is nothing compared to trying to build a layout where a solid 3/4 of the components are gonna be socketed or turned into trimpots

[commodorez]

Thy Graphics

A graphics card for the Cactus directly patterned after the OSI-440, with a few modernizations and optimizations.

I've replaced the eight 2102 SRAM chips with a pair of 2114s. I've also swapped the 2513 character generator ROM with a 2816 EEPROM which gives me not only lower case letters, but pseudo-graphical characters not unlike PETSCII. I've re-implemented the address select logic using modern parts (thank you 74688), and swapped the open-collector NAND gate based video/sync combiner circuit with one I copied from a PET video combiner circuit using 4066 analog switches. I didn't like how vague the delay taps were described, so I added in some jumpers to let the user pick their delay timing.

And hooo boy this had some motherfucking BUGS in it.

Vertical sync polarity was backwards.

Video pixel data was inverted too.

In fact, so were the DIP switches for the address select.

I also got half of the 74123 resistor/capacitor inputs backwards due to not paying attention to the idiosyncrasies of the symbols in my old version of KiCAD.

Oh, and the character ROM I stole from my OSI-540B replica has inverted bit order, so the characters looked backwards.

Every single problem I had was due to something being backwards.

Nothing a little debugging can't fix. Took about 7 hours of tired stumbling with help from friends in the retrotech crew to figure out all the little faults and work around them, but in the end...

It works! It fucking works! The Cactus has video! I made a fucking video card from scratch! I didn't use any dedicated video chipsets or FPGAs or microcontrollers or CRTCs or any of that shit. I didn't make VGA, I made composite video.

All 24x24 usable characters on screen in monochrome goodness from this tiny little PCB. Now onto the Rev B design!

[catenary-chad]

research tips for electric train whump:

-INDUSTRIAL MAINTENANCE SOURCES ARE YOUR FRIEND! There’s not much stuff specifically about trains but basic concepts (maintenance and repair of AC or DC motors, transformers, rectifiers, other heavy electrical equipment) largely carry over from sources about elevators or substations. There’s a lot of good videos on youtube about these topics, look into stuff aimed at apprentice electricians or industrial maintenance, it will generally be more visual/metaphor and less math-heavy if you struggle with that.

-many “breakdowns” are actually due to power infrastructure issues- third rail and catenary wires have different problems and these further vary based on how old they are. Fixed-tension catenaries on the former Pennsylvania Railroad are a notorious issue. The more modern the line, the less weird stuff you’ll have, but much of the US, parts of the UK, and a number of spots in mainland Europe have more unusual and antiquated electrification systems. And this is also an issue with model trains between brands and eras!

-On a related note, pantograph designs have varied by time and place and have different advantages/disadvantages/issues. You even have times when they have a uniquely bad time with old catenaries, like old Comet EMUs specifically getting snarled in those constant-tension PRR catenaries

-Never underestimate how “dumb” and un-computery a lot of electric trains actually are, especially circa the 80s. “Toaster” isn’t even an inaccurate insult for older DC-motor trains, they literally brake using huge resistors that put out a ton of heat… like a giant toaster. And the really old, simple stuff tended to last a stupidly long time in service so you can 1000% wave off a 20s-era engine or EMU in the 80s.

-If you want some really easy ones that have actually happened before: connecting to too strong of a power source and getting FRIED, and having wires ripped out willy-nilly by techs not familiar with electric trains that don’t know what they’re doing. Weaponized incompetence with anything electrical checks out with how even a lot of train people know very little about it and don’t care.

-model trains also have a lot of beginner-friendly electrical info you can work from

[techav]

On Bodging Silly Mistakes

After a few weeks of rest and working on non-homebrew-related projects since getting my 68030 stack running 8-user BASIC, I've circled back around to the project. My goal is to have it ready to exhibit for VCF Southwest 2025 in June.

The first thing to do when picking up an old project is to make sure it still works to begin with.

It did not.

The computer would start up, go through its boot process, and start the user programs. The supervisor terminal would accept and execute commands, but none of the user terminals would accept input.

I could tell the serial data was making it to the machine, because my 8-port serial card has indicator LEDs on the Transmit & Receive signals and they were working as expected. If I held down a key as the system booted, it would print that character a few times before stopping and then no longer accept any more data. So it really looked like the hardware was working. Nothing had changed in software so that wasn't likely to be the issue.

It reminded me of the problems I encountered with reading from disk when CPU cache was preventing the updated disk status bit from being read. The serial card supports asserting the CPU's Cache Inhibit signal, but perhaps that circuit wasn't functioning. There was no change with it connected or not. Time to break out the oscilloscope. The Cache Inhibit signal was always low — always asserted. Cache wasn't the problem because cache was effectively always disabled.

Out of ideas, it was time to break out the logic analyzer. The I/O Read & Write signals on the serial card were working as expected, and it was properly addressing the card & its individual ports. So next thing was to check was the actual data being read from the UARTs.

Letting the logic analyzer run and watching the data fly through, the problem finally made itself known — the UARTs were not setting bit 0 of the status byte to indicate that they had received data. The data was getting to the UART, it just wasn't acknowledged.

But why? And why did it work initially on restart and then stop? And why did it work without issue a few weeks ago? What is different?

What is different, indeed. I have made one change to the hardware since I last ran it — I added a proper watchdog/power-on-reset controller. If the power supply drops below 4.7 volts, it will reset the computer. The power supply I had been using was marginal and was getting caught by the watchdog, so I switched to a proper power PC supply.

So what's different since last time I ran the system is my reset circuit is more effective and the system voltage should be much more stable 5V.

And that's when I realized a mistake I made in the design for my 8-port serial card. The 68k reset signal is active-low and the 16C55x UART reset signal is active-high. I was trying to minimize part count, and didn't have an inverter for the reset signal, so I used what I had on hand — a buffer with an active-low enable signal.

Anyone well-versed in electronics may already see the problem.

When the CPU-RESET# signal is asserted (low), the buffer will set its output, IO-RESET to match its input, VCC (high). That's great, we get a high signal on the output whenever the CPU Reset signal is low.

Except ... what happens when the CPU Reset signal is not asserted? The buffer goes open-collector and doesn't pull the IO-RESET signal one way or the other; it's just left floating.

Floating signals are bad news for digital circuits. Their behavior is unpredictable and subject to environmental noise, power fluctuations, etc. For my IO-RESET signal to function properly, something needs to pull it low whenever the 74'125 buffer is not actively driving it high. A good-sized pull-down resistor should do the job just fine, so I dug through my stock and found a 3.65k surface-mount resistor and bodged it onto the back side of the board.

And sure enough, that fixed the problem!

It is possible that when I was running the system on that marginal power supply previously, the IO-RESET signal was able to stay just low enough to not trigger reset on the UARTs. Or it could have just been different environmental factors.

I'm glad I took the time to test the machine today, and I'm glad this bug came up. It's the kind of bug that could easily have come up when running in a new environment for the first time — such as on the show floor at VCFSW. Far better to run into a bug like this at home with access to all of the tools (and time) to figure it out.

Now that things are up and running again I can continue my testing and setup for VCFSW.

[adafruit]

The first test for our WLED board codename "Sparkle Motion" 🌈💖💡 … 🐇⏳🌌

We got our WLED-friend PCBs today, and we only made one mistake: the wrong resistor on the 3.3V feedback line. Now that it's fixed, the board seems to work great with the latest version of WLED

We are checking all 4 signal outputs with this handy 256-LED grid that sits on our desk. Next, we will test the onboard IR receiver, USB PD, I2S microphone, extra I/O pins, and I2C. We'll also do an Arduino IDE board definition in case folks want to use it as a generic ESP32-to-LED-driver board. We're calling the board "Sparkle Motion" for now, but if you have other naming ideas, let us know - if we pick your name, you get a free board

Sign up, coming soon.

[as-tr0p3]

>I want someone to take me apart. I want to feel her soft hands, [meticulously] taking me apart, piece by piece. And once I'm open, I want her to work on me. Fixing me fr0m the inside. Replacing parts, running recalibrations. I'd feel her gentle touch on me, replacing a [gear] here, or a [resistor] there. Maybe she's humming a soft tune while she works on me. I wouldn't have to think. And once she's d0ne, she will start putting me back together. I'll feel the parts come together, and I'll be whole again, but also, better than I was before.

[ultrajtb]

Alright day 2 of this. Gonna be a long one since the 2 characters I’m covering today are probably the most significant in the Steve Saga

Alright so Nightmare Steve in SS Origins

My issues with his design are pretty simple. His base skin doesn’t match the actual yellow steve design, and his entire body is on the wrong skin layer so he’s fat and bald. Pretty easy things to fix. For fun I also changed how his eyes look so they look more like they’re glowing.

I didn’t really watch a lot of Origins so there’s probably gonna be some stuff missing here, but I’ll try my best with what I remember.

Nightmare started out as a yellow steve but at some point ended up using his power to manipulate energy to absorb steves, starting with a red steve. This gave him his red eyes and his pyrokinesis

In the original series, it was revealed that he did it because Elemental Steve was controlling him. I’ve always felt that that was a bit of a cop out so they could redeem him, so this version will have the old motivation of being sadistic and power hungry with a desire to rule over the species.

So after nightmare absorbs the red steve, he gets a taste for that power and continues, absorbing several more. After a while he manages to track down a blue steve and absorb him, giving him a boost in intelligence and allowing him to mix the powers of pyrokinesis and hydrokinesis into one, allowing him to now create and control lava alongside his fireballs

With this new power he’d name himself king of the remaining steves. Obviously those who were left didn’t like this, dubbing him the nightmare king. They’d attempt to rise up but he was too strong for the base colors. This leads leaders of the 5 colors to come together, sacrificing themselves to create a being who can stand against Nightmare Steve.

They gave up their lives and combined their energy to create Rainbow Steve: The Beacon of Hope

Okay so what bothered me about Rainbow’s original design was that his highlights weren’t very visible and his colors were kinda muddy. So I gave him some highlights and brightened up his colors.

So lore time. I’ll be honest I remember even less about Rainbow in SSO.

So Rainbow is created with the intention of being someone who can defeat nightmare. Unfortunately, he has no idea how to use his powers. Luckily, there are these artifacts that can help him channel his powers until he can learn to use them properly.

There’s an artifact for each color

Red is a redstone block, blue is a Diamond block, green is an emerald block, yellow is a gold block, and purple is an amethyst block.

Each one can help rainbow channel his abilities to their full potential. Not only would he be able to wield the base powers of all 5 colors, but with enough practice he’d be able to go beyond them.

Red: base power is regular fireballs and fire creation. The beyond power would be larger fireballs and no longer needing to consume a lot to fuel them

Blue: base power is generation and manipulation of water aka hydrokinesis. The beyond power would be cryokinesis, or generation and control over ice

Green: chlorokinesis (plant control) as a base. Geokinesis (rock control) with mastery

Yellow: superspeed and lightning. Beyond would be movement within a fraction of a second and generated lightning not being limited by conductors and resistors

Purple: teleportation. Beyond would allow him to teleport greater distances with others

So once nightmare learns about Rainbow and how he needs the artifacts to match him faster, nightmare sets out to find and destroy them all.

Rainbow manages to get the red, blue, and yellow artifacts while nightmare manages to destroy the green and purple ones

Throughout the journey, nightmare will be making advancements of his own, such as his discovery of shadow stone. With the new substance he carries out a few experiments (which will be expanded on in later posts)

Eventually he decides to infuse himself with the substance, giving us the nightmare we see in SS. I changed the origin of his markings for 2 reasons. First is that him absorbing a crystal just didn’t make sense to me. Second is that when he broke himself down to become a normal yellow steve again in the original, shadow stone was removed from his body.

My issues with the original are the same as the origins one. The only new change here is I made the eyes pure red to emphasize how much more corrupted nightmare has made himself.

So throughout origins nightmare is basically torturing Rainbow. His goal is to break his spirit and show the remaining steves that there is no hope. He plans to eventually just kill rainbow once he’s made sure to stomp out any hope left.

After nightmare kills Rainbow’s best friend, a blue steve, Rainbow realizes that despite how far he’s come, he’s still no match for nightmare. So he allows himself to go into a hibernation that’ll allow his power to build up over generations, making him strong enough to stand against nightmare. By the time he wakes up, his and nightmare’s origins have been lost in legend

Now there’s a lot more to this stuff, but I wanna put it in other posts with other characters. I feel like I probably forgot about something important but I’m not really sure.

Lmk what you guys think and if you have any ideas of your own that you’d like me to add. Next post comes out tomorrow.

Have a good day/night

[poupeebotfan97]

Care For A Smoke, Mr. Powers ?

After recovering the memory bank from the destroyed Fembots from the ruined lair of Dr Evil in Vasquez Rocks. Dr.Evil, Frau and the rest of the Fembot Team concluded there were serval problems with the Fembot designs. One is the effects of smoking. As soon as Austin puts cigarettes in their mouths, their processors think the cigarettes are their chargers, this messed up their CPU even more because instead of a charger; it’s smoke! So the Fembot Team went to work and fixed this problem and created a Fembot that couldn’t be affected by cigarettes anymore! No matter how many you throw at her, she would smoke it like nothing. The Fembot could puff smoke into heart shapes! Now, all they need to do is add a mojo resistor to the Fembots, and nothing can stop them—not even Austin Powers! 

[piratesexmachine420]

For future reference (my own and others), if your TI SilverLink USB cable stops working and starts showing up as "TUSB3410 Boot Device" or similar under device manager (AKA this issue on TI's help page), this is how you can fix it:

Download the TUSB3x10 EEPROM Burner. This is a Windows-only program, but to my knowledge will work on basically any windows machine from XP on -- so long as it's got USB ports. No clue if it'll work in a VM. (You might want to consult this user's manual.)

Download the SilverLink firmware. I got it from here, and compiled it from their de-compilation. It's just a standard 'make' to build. The output file you're looking for is called "ti_graph_link_silver.eep".

Rename "ti_graph_link_silver.eep" to "ti_graph_link_silver.bin".

Open the TUSB3x10 EEPROM Burner, click on the options dropdown and click "Show the 'Program Full Binary Image' button". (page 7 of the manual).

Select the entry under "Computer" labeled "TUSB3410 EEPROM Burner Instance (1.00)".

Set EEPROM size to "64Kb".

Set "File Path" to point to "ti_graph_link_silver.bin". (The renamed .eep, not the original .bin)

I don't know if the VID, PID, Manufacturer string, Product string and Serial # need to be set manually or not with a 'Full Binary Image' burn. Just to be safe, I set VID to 0451, PID to e001, Manufacturer to "Texas Instruments", Product to "TI-GRAPH LINK USB", and checked "Not Serialized"*.

Click the "Program Full Binary Image" button (yellow triangle with the exclamation point), and proceed with the write.

Unplug and re-plug your cable, and it should show up as a SilverLink again!

Additional notes:

The reason that this happens is because the SilverLink cable (revision b, at least) is based on the TUSB3410 microcontroller. That microcontroller's boot process involves checking for an I2C EEPROM containing program code. If it finds that EEPROM and its contents are properly formatted, it'll copy that code into internal RAM and start executing it. If it can't find the EEPROM, or its contents aren't properly formatted, it'll fall back to looking for boot code over USB. Thus: "TUSB3410 Boot Device". Your cable has, in essence, forgotten who it is and and is begging for you to give it a purpose.

The default page-write buffer size (32 bytes) and I2C bus speed (400 KHz) in the burner app are already correct, so no need to change them.

*I don't remember exactly what the Manufacturer string, Product string, or serial number fields were set to pre-corruption. Likewise, no idea about the advanced descriptor options. If someone wants to send the output of lsusb -v -s [whatever their silverlink's bus/id numbers are], I'd really appreciate it!

You might be able to skip the header rigamarole by taking the ti_graph_link_silver.bin file directly ("directly coming from the compiler") -- but I again I don't know exactly what information is in the .eep file and what isn't. Are the PID and VID encoded somewhere in there? I peeked with a hex editor but have no clue. If someone has hardware lying around they're willing to experiment with/potentially brick, I'd love to hear your results!

If you mess up and accidentally forget to do a "Full Binary Image" write, or otherwise brick the firmware, you can force the TUSB3410 to fall back to USB boot mode by opening the plastic shell around the PCB (one Torx screw under the sticker, then just normal plastic tabs) and shorting the right-bottom (Vss) and right-top (SDA), or right-bottom (Vss) and center right-top (SCL) pins of the EEPROM (the chip labeled "24LC64") as you plug it into the USB port. You may need multiple attempts. This works because it temporarily convinces the TUSB3410 that the EEPROM is missing/corrupt, and thus it decides to fall back into USB boot mode -- until you reset it. It might be better to do this with a ~1k resistor instead of a jumper wire, but IDK I'm not an electrical engineer. All I know is that shorting Vss and SDA worked for me. Again, would love feedback.

No clue what causes the corruption in the first place, or how long this fix will last. It might be because the EEPROM's write protect pin is set to "write enable"? It could also just be degrading hardware, for all I know, so no idea how long the fix will last. All I do know is that everything seems nominal right now (immediately after performing this procedure).

[mychlapci]

I don't go here but I do work with fixing machine wires n motherboards n such for my day job n I'd like to propose that capacitors are erogenous zones a la nipples, resistors are like prostates, and transistors are like that one spot in the mouth for people with oral fixations.

OoOh we don't do enough plug and play honestly... I love that, honestly, various internal components being erogenous zones with different responses, that means bots have to learn which parts are which or at least which parts elicit the response they want.... inch resting