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Does this look like a JST SM04B-SRSS-TB connector? Pitch is 1mm and the housing dimensions match (6mm) so it looks like it. https://www.jst-mfg.com/product/pdf/eng/eSH.pdf   It's an unpopulated fan connector on my laptop. There seem to be none in country, digikey has them (https://www.digikey.com/en/products/detail/jst-sales-america-inc/SM04B-SRSS-TB-LF-SN/926710) but it's like $30 in shipping charges for one plug and contacts lol.
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May 11, 2023 09:59
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ante posted:Or pick up a Rosco gel swatch book Yeah I was just about to suggest "they specifically make things called gels for theater lights that are plastic sheets designed to adjust color temperatures". It'll be more fiddly and prolly a bit more expensive than kapton tape but that'll absolutely let you dial in exactly how yellow you want your hams to look without swapping out the LED's, assuming you can get the plastic sheet to stay in place somehow. Also never stop posting about your ham yellowing project it's been a hell of a weird trip lol Shame Boy fucked around with this message at 15:29 on May 11, 2023 |
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May 11, 2023 15:26
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mobby_6kl posted:Does this look like a JST SM04B-SRSS-TB connector? Actually it looks exactly like the connector on the back of this cheap mountable camera I bought a while ago that I've been wondering what the connector type was, so thanks 
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May 11, 2023 15:28
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Shame Boy posted:Actually it looks exactly like the connector on the back of this cheap mountable camera I bought a while ago that I've been wondering what the connector type was, so thanks Found them on ebay on more reasonable terms. Shipping's going to take forever but I'm not spending >$30 for a single plug. https://www.ebay.com/itm/334694464003 It has to be the correct type, there was nothing close on digikey and I can't imagine there being some other exotic connector that is almost, but not exactly, like this one.
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May 11, 2023 18:31
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mobby_6kl posted:Does this look like a JST SM04B-SRSS-TB connector? JST SH 4-position connectors are used to connect I2C dev boards and maker stuff: Adafruit STEMMA QT and Sparkfun qwiic. Maybe this can help you find a local supplier? Look for shops selling Arduino stuff, 3D printers, hobby-level robotics supplies. Which country?
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May 11, 2023 18:34
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well after all this, i got my new freezer light, and it was in fact the one i needed, the revision 3.0. i guess none of these sites updated their pictures.
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May 11, 2023 19:06
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ryanrs posted:JST SH 4-position connectors are used to connect I2C dev boards and maker stuff: Adafruit STEMMA QT and Sparkfun qwiic. Maybe this can help you find a local supplier? Look for shops selling Arduino stuff, 3D printers, hobby-level robotics supplies. 1mm pitch in that kind of form factor is extremely rare. I had to read the datasheet to believe it
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May 11, 2023 20:51
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ante posted:1mm pitch in that kind of form factor is extremely rare. I had to read the datasheet to believe it Yeah it's a weird connector and I'm always afraid I'm gonna break it when I have to unplug / plug it in, which is why I was happy to find out what it was if I need to replace it lol
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May 11, 2023 21:38
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If you're making I2C dev boards for tiny sensors like accelerometers, you want a small connector. There is a big ecosystem based on these specific 4-pin connectors, with hundreds (thousands?) of available devices.
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May 11, 2023 22:20
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The camera I'm using uses it for the USB connection, because there's literally no other available miniature, or even micro-sized USB connector out there I guess.
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May 11, 2023 22:24
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Yeah they're really tiny and I wasn't looking forward to having to crimp these manually with pliers  Good idea with the STEMMA QT stuff, it might be easier to get a complete cable for a few bucks than ordering a unicorn connectors and contacts by themselves.
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May 12, 2023 00:31
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OTOH, if you do decide to buy from Digi-key, get the SH pre-crimped leads. Then you just insert the contacts into the housing, which is easy. Digi-key will also crimp contact/wire combinations that don't have catalog numbers, but you have to email them for a quote. This is good for custom lengths or adapters. Last time I did this, they charged a $20 engineering fee, plus some small amount per wire, plus catalog prices for the contacts and wire. It's pretty cheap.
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May 12, 2023 00:56
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Extremely cheap knock offs of pretty much all JST connectors can be found on AliExpress or equivalent if you really want to save money and aren't in a hurry
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May 12, 2023 02:30
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Yeah you can probably get 100 connectors for a dollar on AliExpress if you're willing to wait three weeks.
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May 12, 2023 02:59
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Yeah you're right, there are tons of them. https://www.aliexpress.com/item/4000820462275.html I don't know why I didn't find any initially, probably just directly copied the part number from the datasheet which they of course don't list.
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May 12, 2023 08:49
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Anyone here like soldering and making projects but find theory incredibly dull?
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May 12, 2023 13:31
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I would blow Dane Cook posted:Anyone here like soldering and making projects but find theory incredibly dull? I'm going to go out on a limb and say that forums poster "I would blow Dane Cook" falls into this category.
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May 12, 2023 14:01
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I would blow Dane Cook posted:Anyone here like soldering and making projects but find theory incredibly dull? Solution: use 0402 parts to make the soldering less fun. realtalk: You don't need to know much theory to build cool stuff. Ohm's Law + datasheets + app notes will go a long, long way. You will get more mileage out of knowing how to program an Arduino than knowing how to use LTSpice. Your capabilities will expand with each new tool you learn, but you don't need much to get started. ryanrs fucked around with this message at 19:41 on May 12, 2023 |
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May 12, 2023 18:29
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ryanrs posted:Solution: use 0402 parts to make the soldering less fun. Feels very true. I never did anything analog but feel like digital is way easier to cobble something together without actually knowing poo poo  I'd love to learn more theory but mostly I'm happy when it just works
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May 13, 2023 01:31
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Guess what I get to fix on Monday? One of the guys that I don't officially supervise, but apparently am still somehow in charge of anyway, decided that this was an acceptable outcome after being tasked with removing a DIP switch bank from a fairly important board. For reference, this is about 1.75" wide by 3.5" tall. I'm like 17 goddamn years out of practice doing proper miniature PCB repairs, and apparently this is how I get to re-hone my skills, because a whole new board assembly is fourty-nine-loving-hundred-dollars. $4900. In real US dollars. Kids, if you need to get into a specific electronics field, aviation-related poo poo is apparently where the money is. Already going cross-eyed just thinking about unfucking this. I'm actually sure I can still do it, I just have to dredge the knowledge up out of my aging brain. [sigh]
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May 13, 2023 02:03
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I would charge less than that to reverse engineer that simple-rear end board and remake it
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May 13, 2023 02:25
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yes but that mangled piece of poo poo has the right airplane paperwork
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May 13, 2023 03:45
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Apparently the refrigerator broke while I was on travel, so now I'm learning what the hell a run capacitor does. AC is weird.
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May 13, 2023 03:45
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I would blow Dane Cook posted:Anyone here like soldering and making projects but find theory incredibly dull? To each their own, but I really like the theory phase. You get a new problem, read up on different technologies that could help solve it, play around in a simulator to find the optimal solution. It's creative and intellectually engaging. Reducing the design to a working model is just a ton of reading data sheets, picking specific components, laying out the board, hand assembling the first prototype in stages, and testing to see if it works. Generating parts lists, documenting it, waiting a month for everything to come together is complete drudge work. So many of my personal projects die in the "it works in LT Spice" phase. But on the other hand, watching a new board come back from the CM and light up for the first time and do exactly what you designed it to do is always a bit of a  moment.
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May 13, 2023 04:20
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I would blow Dane Cook posted:Anyone here like soldering and making projects but find theory incredibly dull? Yeah, I don't spend enough time studying or designing circuits to really grok EE, but I love making a nice clean solder joint or wiring up a custom controller and having it work.
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May 13, 2023 05:22
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Oops. This is a mechanical footprint for an LCD display. The display is connected with flex cables, so this footprint has only silkscreen and a cutout. But KiCad was getting confused about what is inside/outside of that footprint cutout, turning the cutout into a small board. So I put down a lone pad as a hint for KiCad to figure out the topology, and that worked. But then I forgot to lookup the correct way to do it, and left the fake pad in the gerbers. It's fine, but it's also nice that the fab house caught it. (And that weirdo fid in the middle of the board is a landmark for dimensioning the enclosure in Solidworks. It's not for PnP.)
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May 13, 2023 05:57
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I did that MITx free online "electronics intro" course that had all the stuff my dad (an actual electronics engineer) would have done at college like figuring out the sum at every node in the circuit to work out exactly how everything works and everything. I forgot all of it, but I understood it at the time, so I still feel like I accomplished something and I feel like it did slightly improve my understanding of general electronics even if I'm still just doing digital stuff. Also it had a lot of homework and it was surprisingly hard.
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May 13, 2023 06:37
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I built a new board for audio stuff. Probably the most complex board I've assembled myself. As usual, I used too much solder paste and bridged like 20 pins on the ICs. But I got real good with the solder wick so it turned out okay. It works really well except for one stupid mistake: I picked the wrong QFN size for the headphone amplifier footprint. Doubt I can bodge-wire my way out of that one, so no headphone output on this rev. During rework I did a spot check with a continuity tester and dishearteningly found that every single through-hole pin on the board was shorted. After 10 minutes cleaning up the relevant IC pins, I realised that none of them were actually shorted. I'd placed the board on a sheet of tinfoil to spread heat and the probes were touching it through the holes lmao
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May 14, 2023 20:16
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Could I bodge the QFN by making a tiny little new board for it? Like with the old footprint on the bottom and the new one on the top?  Or maybe a tiny breakout I can stick on with more bodge-friendly pads would do the trick, since only 6 wires are needed.
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May 15, 2023 17:41
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Yeah, option number two is fine. I've tried making footprint adaptors that would just solder on nicely, and it's never really worked out
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May 15, 2023 17:49
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I tried using a flex PCB as a tiny adapter to fix a buffer miswiring issue once (control pins were referencing the wrong, higher voltage so the microcontroller could barely activate it, leading to strange lag) and it was easy enough to solder the PCB to the board but I lost interest in soldering the chip to the flex PCB (instead I just cut the traces and soldered voltage shifter ICs in instead, which I told myself was easier). Also two chips had the problem so the flex PCB did it twice.
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May 15, 2023 19:41
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I'm clearly not searching for the right term, does anyone know of a barebones PCB-mount banana test jack? Picture what you see when you take apart a handheld DMM, the metal tubes sticking up off the PCB. I probably don't need much more than a 5mm tube with pins on one end, but somehow I can't find anything like that. A threaded end is OK too if I just make a large plated through hole on the PCB or whatever. These are just for test boards, for power in and out and hooking up one of those high voltage diff probes for a scope that has builtin banana cables. That sort of thing. Not a finished product just for testing purposes.
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May 16, 2023 18:35
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If you don't care about long-term durability you can take a swage-mount connector like the keystone 575-4 and just solder it in. I do it with turrets all the time (but I guess I'm not jamming plugs into the turrets). Works well enough but looks like the sort of thing that would crack the solder eventually.
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May 16, 2023 19:06
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Rescue Toaster posted:I'm clearly not searching for the right term, does anyone know of a barebones PCB-mount banana test jack? Picture what you see when you take apart a handheld DMM, the metal tubes sticking up off the PCB. I probably don't need much more than a 5mm tube with pins on one end, but somehow I can't find anything like that. A threaded end is OK too if I just make a large plated through hole on the PCB or whatever. I think those are called safety jacks. I had a glance through my Pomona catalog and found this: Model 73096 Safety Jack (PCB Mount) edit: fixed link babyeatingpsychopath fucked around with this message at 20:18 on May 16, 2023 |
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May 16, 2023 19:29
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babyeatingpsychopath posted:I think those are called safety jacks. I had a glance through my Pomona catalog and found this: Model 73096 Safety Jack (PCB Mount) Your link doesn't work. red and black Poking around online, they also come in right angle. Newark has more colors too: https://www.newark.com/c/test-measurement/test-connectors-ic-test-clips/banana-plugs-jacks?connector-mounting=pcb-mount
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May 16, 2023 20:15
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Rescue Toaster posted:I'm clearly not searching for the right term, does anyone know of a barebones PCB-mount banana test jack? Picture what you see when you take apart a handheld DMM, the metal tubes sticking up off the PCB. I probably don't need much more than a 5mm tube with pins on one end, but somehow I can't find anything like that. A threaded end is OK too if I just make a large plated through hole on the PCB or whatever. This is the most bare-bones thing that comes to mind, literally solders into a big plated hole on the PCB: https://www.digikey.com/en/products/detail/keystone-electronics/575-8/318495 Or this if you want threads: https://www.digikey.com/en/products/detail/keystone-electronics/6095/316532 If you want it insulated: https://www.digikey.com/en/products/detail/keystone-electronics/6092/316529 Keystone is great for this sort of basic connector stuff.
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May 17, 2023 13:22
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ANIME AKBAR posted:Keystone is great for this sort of basic connector stuff. I'm getting a Keystone catalog to put next to my Pomona catalog. These are great bits and bobs.
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May 17, 2023 14:12
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ANIME AKBAR posted:Keystone is great for this sort of basic connector stuff. This right here. There are a couple connector companies it helps to know: Keystone, Molex and if you restore old stuff like I do, Switchcraft, Amphenol...
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May 17, 2023 19:00
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This lil' guy has been giving me a headache.    It's part of a masttop wind instrument for my sailboat. It's probably at least 20 years old and it doesn't work anymore. I think it may be fixable though, and I'd prefer that to replacing it, because new ones aren't compatible with my ancient display system (with other instruments such as electronic compass, speed transducer and depth sounder and water temperature probe hooked up to it). Let's start with how it works. I found a guy who did a deep dive on these things which helped a lot. The board sits vertically at the top of the instrument arm and you can see the two black "ears" sticking up above the bearings:  The propeller and wind wane assembly is free to rotate into the wind, and as the propeller spins it rotates the black and white marble. The pattern on the marble is a sinusoid, and in the "ears" (which are set at a right angle to each other) there are IR transceivers of some kind that can tell black from white. What you get from the board is two PWM signals, where the frequency encodes the wind speed and the two duty cycles together encode the angle of the marble relative to the IR transceivers (and therefore relative to the boat).  The big brown thing at the top of the board is a varistor; the thing runs on 12V and since that could be straight from an alternator it's almost certainly for circuit protection. The only other IC is an LM317LM 100 mA voltage regulator. Now, I've got an USB oscilloscope and a multimeter and I've at least figured out GND and +12V so I've managed to run it on a test bench. What I find is that it appears to be partially working - it draws 0.2W and when I cover one of the IR transceivers with my finger it toggles one of the data pins between high and low. The other pin though stays low no matter what I do. The board was covered in some kind of shellac or something but I've managed to clean some of that off with Q-tips soaked in isopropyl alcohol so I can probe it. I found that the IR transceivers both appear to be working - seen from the sensor side the middle pin is GND, the right appears to be VCC at 1.25V ish, and the left pin is signal. It's high (10V or so) when the sensor is uncovered and drops to 7V ish when I cover it with my finger (what are these things even, I can't find anything that looks or behaves quite like this). So the fault appears to be in the signal conditioning somewhere, which makes things difficult. I can at least identify most of the components - there are only really resistors, capacitors (no idea what their values are though) and three kinds of SOT-23 packages where one appears to be a wacky two-diode combo and the other two are NPN and PNP transistors respectively. Also, all traces are visible and the board has no copper planes so I could probably draw a complete circuit diagram if I had to. The problem though is that I'm a soldering novice and have no equipment whatsoever for SMD work, and even if I did I don't know a good strategy for isolating the failed component(s). At least I suspect it's not one of the passive components? Probably? So, where do I go from here? I was thinking I'd try to check if the transistors work but I'm unsure if I can do that without first desoldering them from the board. Where do I start learning about SMD soldering?
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May 18, 2023 23:40
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I'd start by checking the continuity from each of the 6 pins on those IR sensor "ears" up there to their traces on the board. It may be an optical illusion but it really looks like one of the pads has broken off in your first photo. Maybe wiggle it a bit while your meter probes are on it to make sure it's not intermittent. Beyond that, maybe blast your dead channel's sensor with a TV remote to see if it's the sensor or the LED (I guess I assume these have some source in them). If that’s dead, you have to start tracing the signal path with your scope (or a voltmeter since we're talking about slow things that you control). Luckily you can use the known-working channel as a reference and you only have to go until the signal stops.
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May 19, 2023 01:12
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