Buy the JST plug with the right pin pitch (in your case 2mm), and grind it so it fits. You can find male to female cables, so you also don’t have to modify the original connector on your noctua fan.
I am trying to be non-destructive since this is a rare piece of equipment. So I would prefer to put in something entirely new in and preserve the original hardware in case something goes wrong.
One possiblity would be to cut the original cable and add a new connector to both sides. A female one to the one that goes to the board, and a male one to the one on the fan.
That way you have all the original parts still there, but you can use the one part of the cable as an adapter.
Any chance to replace the whole PSU and then going full tilt modifying the replacement? I only see one offer for 400-5494-91 (400€!!) so maybe any other in that form factor? Seems to be mostly standard PC connectors on these, but not sure from the pics I can find.
On a KISS basis - I tend to just use a bimetallic switch or omit the temperature control and just run the fan from power up. It’s possible for a processor to suffer some non-handled exception where it no longer executes the temperature management routine.
it worked! (at least in the sim)
thanks a lot!
I'm not sure I got all the math right, since I get 0 - 5.05V on the output, but it's not a deal breaker for me.
I attached the schematics, but not sure that images in comments federate from kbin to lemmy, so if you don't see it, try opening an original link to this comment.
ah, a little bit of thinking helped me realize that I don't need 1k in inverting loop and then I'll get 5v instead of 5.05v :) and 100k can also be replaced by 1k
No, with 0 Ohm I get a perfect 0+5v sine, just as I need. It's the other way round, it'll amplify the signal and clip off the top at about + supply voltage when you increase the resistance in the feedback loop, but it's not exactly square wave, as the bottom part of sine will remain intact. I use clipping schottky diodes to protect the arduino from voltage outside 0+5v range, this way if you increase input signal to say 20v peak to peak, you'll get more square-ish wave in 0+5v (I've attached the schematics)
You’re right of course. Two more questions if you don’t mind:
what’s the 1k || 100k doing?
if you don’t want more than 5V at the output of the OpAmp, wouldn’t it be easier to just supply the OpAmp with 5V instead of adding a shottky diode which has a forward voltage of around 0.6V? As I understand the screenshot the voltage is 5.4V at that exact point and it could theoretically raise to 5.6V.
At the moment you’re also mixing up your + input. 10V AC + 5V DC result in 7.5V input in your sim.
it does nothing 😅 I just forgot to remove it from the sim
you mean like power it with 0+5v? I think it won't work with negative input voltages then, right? and I'm using tl074 and I'm not sure that 0+5v is enough juice for it, and I use remaining 3 opamps for other stuff, so it's not really an option for me. the sim didn't have shottky diodes, so this measurements are not 100% accurate, but I used this approach to protect arduino inputs in another project, and it worked well. And yeah, I cranked up the input signal to +/-10v just to check the clipping, it'll normally stay within +/-5v
I already ordered PCB for the prototype. I hope it'll work fine. Thanks a lot for your help :)
I suggest that you give details of the iron (and tip) and solder that you are using and a close up photo of the wires that are being problematic.
The iron temperature control may be faulty and the iron just not getting to soldering temperatures. Or you may have it set too low.
The thermal mass of typical USB wires is so low that, if the solder actually melts freely at the tip end when not soldering anything, it should do so when soldering these wires.
This was a few months ago so I can’t recall a lot of the specifics unfortunately.
What I can recall was using a 90w Ali Express soldering iron with a conical tip to solder a damaged original Xbox controller cable. The leaded solder seemed slow to melt on the tip but wouldn’t melt to the wire when I applied heat on the under side.
Sorry I can’t tell you more. I was looking to do some practice this weekend and wanted to know if I should be ordering a thicker tip or something.
The temperature is set too low. The solder should melt almost instantly when applied to the tip if the iron is set to 350°C.
Those fine point conical tips that typically come with soldering irons are terrible. Get a 2-3mm chisel tip, that will be suitable for most soldering jobs.
Wattage does not mean how hot it gets, it means how fast it gets to the desired temperature. Also Chinese vendors tend to exaggerate greatly with specifications, especially with cheap products.
With soldering you want to maximize heat transfer at all times so flat surfaces (chisel tip for example) are usually ideal. If you want to remove solder from a hole in a PCB you’re better off with a round tip as that has the most contact area then. It will make it easier to use a solder sucker in that case for example. Personally I have the chisel tip on 90% of the time and might be willing to switch to the large flat one.
It looks like 1GΩ (black-brown-white gold). But that doesn't sound likely unless you have a very high voltage bread maker.
If we treat the black band as discolored-brown, and read it the other way, we get (yellow - white - brown - brown) which is 490Ω and closer to your measured value. I wouldn't rule out (yellow - white red - brown) either at 4.9 kΩ, although that doesn't match closely to your measurement.
A good question is 'why did the resistor burn?'. If I didn't know why, then I would assume that replacing it will just result in it burning again, although maybe not immediately.
Well, arguably keeping the resistor the same value would result in a somewhat known state, and changing it would put it in an unknown state. The unknown state could be better or worse. I can't see enough to know what the circuit does to say.
What you could do instead, is set the resistor to the same value, but rated for higher thermal dissipation. Then measure how hot it gets to identify if the real problem is somewhere else. Another part might burn/explode instead though, so I'd consider carefully how to proceed, and probably wear goggles + have a fire extinguisher in the room.
My main concern is by 'fixing' it with a resistor with higher thermal dissipation, I've created a fire hazard because that dissipated heat now has to 'go somewhere', which may be the plastic case. A thermal camera is handy to see if some part of the board gets unacceptably hot during normal operation.
Thank you for the detailed insight! I miss some basics in electronics but am eager to learn how to test and fix circuits.
Years ago I tried to repair an old keyboard/synthesizer by cleaning it and replacing leaked/bloated capacitors. Unfortunately the onboard sound memory could not be loaded anymore or was wiped entirely as far as I understood. But due to lack of knowledge (me and community that time) it was too complex to got the keyboard up and running again. It’s sometimes sad to loose good hardware…
Back to the resistor/thread: I can’t imagine a resistor to be the source of the problem. Isn’t it more possible that a capacitor wears out or a transistor cooling fails?
However, if the circuit was in an abnormal state (e.g. the contact with the case), then a resistor could very well blow. It would not be surprising if it took some other components down with it, and that this damage is not obvious yet. “The transistor blows to protect the fuse” is a common fail-state, facetiously stated.
Another possibility is just… bad design. You could call me adequate at circuit design (I mostly design prototypes, not finished systems that have to last thousands of hours), but regularly see commercial products designed poorly with some stupid point of failure. For example, using a 1 watt resistor that is dissipating close to 1 watt, instead of designing a more efficient system that doesn’t require dissipating heat at all.
I spend a lot of time answering questions for people just getting started. Probably 75% of them boil down to a few things. Here is that list in case amusing / useful:
Relays are not a great solution in general, and there are many better alternatives (MOSFET, SSR, etc).
Output impedance matters: you can’t power a huge motor off a microcontroller pin.
Back-EMF from inductive loads can burn out your control system unless you add a protection diode.
Lead acid batteries aren’t a magic solution to power everything. Especially automotive ones. Understand and use lithium ion.
Connecting LEDs in parallel then adding a single resistor will lead to failure pretty quickly.
Generally, don’t pass significant power through a switch. Use the switch to control the state of a power MOSFET or similar.
Button debouncing.
Most of the rest is refusing to do other people’s homework, help people build weapons, or do unwise things with mains power / high voltage / centrifuges. Occasionally people ask me really interesting questions though, so I don’t mind that the interactions are a bit scripted the rest of the time! I’ve noticed on Lemmy I’ve gotten much more interesting questions so far!
The case is basically fully metal, just a bit of plastic inside for mounting the PCB to and a few other bits of plastic outside. Plus there is a temperature fuse in the case also.
From the resistor size (11.5 x 4.5mm) I think it would have been a 2W resistor when comparing to sizes on Digikey. I made a 500 Ohm 2W resistor from 8 1/4W 1K resistors then put a larger resistor in parallel to that to bring it down, measured it to 489 Ohms.
I’m going to run it a few times then open it up again to see if there is any new damage to the board before returning it.
Thanks! I’ll try replacing it with a 490 ohm resistor and see if it works again.
The element in the bread maker looks like it came loose a bit and made slight contact with the internal metal housing. I wonder if that caused the resistive element to sink more current than the PCB was designed for, burning out the resistor.
That sounds like a possible fail state. Also shitty design. It should use a resettable thermal fuse or something to detect faults without parts burning.
Outside of a few specific cases, a standard chisel tip is all you need. Yes, even for surface mount.
The wires found in some thin flexible cables (like USB or headphone cables) are sometimes coated. Solder won’t stick unless you get it hot enough to burn off the coating, or scrape it off before soldering.
Play memory or with a wooden kitchen. I’d say 3 is too young. you can get some basic electronics kits for children. just visit one of the toy stores. But playing with electronics and doing experiments starts being fun at around 5 to 8 years. Maybe playing with an extension cord at 4. but you wouldn’t want to encourage a little kid to play with extension cords, plugs and mains power…
Don’t worry, we’re already doing all the typical toddler games and I’m not keen on raising a STEM child prodigy. That’s why I asked for hands-on experiences with prodcuts specifically for toddlers.
Alright. I think i misread things and thought you were after an (strictly) educational kit. Just wanted to say that. We gifted an (quite comprehensive) electronics kit to a seven year old and that seems to be a good age to start. but under 5 i can’t see a kid having the attention span, dexterity or mental abilities to grasp concepts aside from on/off, this is a light and this is a switch. but i may be wrong. there is certainly no harm in starting too early. i just think it wont be fun or of value for a 3 or 4 year old. in my experience they get bored quickly if you try and convey theoretical concepts. at that age i see kids playing with wooden tools, train their dexterity with a small hammer and nails game. or mimick their parents and play something like cooking or doing the dishes, that has something to do with their every day life. nonetheless. try it. i’ll bookmark this and read all the ideas and experiences of other people. maybe i’m completely wrong. one thing i observed kids are interested in all kinds of silly stuff. and they start asking questions as soon as they can. and i believe it is a good thing to encourage them in asking questions and figuring out concepts and how things (including physics) work.
edit: some dads build a big wooden box with (old) sturdy buttons, switches, indicator lamps, a vandalism-proof keypad, etc for their toddlers. i saw a few blog posts years ago. But that was completely DIY. I don’t think it teaches anything but dexterity, but toddlers like pressing buttons. And it’s a cool project. And a few years later you can use it as the main console for your imaginary space ship. ( youtube.com/watch?v=j6zseFi070E )
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