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Really basic and high level question, but I purchased a "non working" piece of music gear (Boss DR-202) recently just to see if there was anything obviously wrong with it. I would not normally have bought it at the $500 or so it typically commands, but at $50 I figured I could take a chance. I'm waiting for it to show up in the mail, but given no context I'm wondering what a good first step would be. Outside of a visual inspection of any capacitors or broken traces or battery leakage, I guess applying power and seeing whether the regulators are pumping out what is expected would be a decent first step, yeah? Next steps would probably be informed better after I open the device and actually see what's inside, but I'm just thinking of my gameplan at this point. Obviously if the damage is in any of the custom circuitry I can kiss that $50 goodbye but I think it was worth a gamble just to see if I can improve my diagnosis skills.
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Feb 15, 2022 13:41
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mobby_6kl posted:Do you know anything beyond "not working", like does it turn on at all? I know nothing about that drum machine but maybe you could also check some forums for known common issues or solutions. E.g. Well I picked up the package today and there was definitely battery leakage. The RF shield looked a little gnarly but not a total disaster:  BUT the board looked pretty heckin’ pristine. There was some teal crystal on the solder pads holding the RF shield in place, but the traces around there seemed to be like-new. In the end I plugged in the 9v wall-wart and it fired right up so I dunno. Maybe it worked and the guy just didn’t have a wall-wart, assumed that since the battery leaked it was dead. But I mean, five minutes in all the buttons respond, it makes the noises I’m expecting, and hasn’t exploded, so.. I got a $500 device for $50 maybe, unless this thing starts smoking in the next hour..
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Feb 15, 2022 17:13
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I finally sourced the original 1992 schematics for a SCSI interface board for my old S950 sampler. They were unobtainium so I had to scour the net until I actually found someone selling a physical copy. Anywhoo, part of me thinks this would be a pretty interesting project to see if I can learn anything fun by literally just trying to clone the PCB in kicad or something.  I’m not certain I’d be comfortable actually building it and risking accidentally frying my vintage sampler in the process, but who knows. I think SCSI ICs of that era are going to be impossible to find anyway, so I’d have to figure out pin or protocol compat parts and adjust layout to suit. I know folks have made (expensive) aftermarket clones with newer ICs so it’s probably just a matter of finding a protocol compatible part, and I think just digging in a little to see what chips they used would confirm. Still way above my skill level to figure out how to adjust the PCB to match so I’d probably have to come back here for advice if I ever get that brave. Anyway, I think maybe just setting a goal of replicating this board and getting a fancy black board printed just to have would be fun so I guess I might have a bunch of kicad questions in the near future. E: here’s the rest just for funsies:    
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Feb 23, 2022 03:00
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Baby's first KiCad question. I need to add a PCB mounted spade connector to my design. Do I need to differentiate that somehow from other connector symbols or do I just add a conn_01x01 and select the right footprint after the fact? Baby's second KiCad question. I'm also adding a connector for +/-12V, 5V, and COM -- presumably the right way to do this in a sensible manner is to just add a basic conn_01x04 and use net labels to label each pin with its intended values? Or is there some function where I can edit the instance of conn_01x04 I just placed and label the pins there? If so I'm not seeing it so I'm guessing the net label thing is the way to do this?
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Sep 7, 2023 01:39
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I need to stop trying to aim for perfection and just draft a PCB. I *always* do this when I get into a technical hobby. I’m drafting a power distribution PCB whose literaly only purpose is to take low DC voltage from one connector and route it to a bunch of other connectors, and instead I’ve been researching PCB design best practices and naming conventions and a hundred other things instead of just placing the components and sending it off for manufacture like five days ago, becasuse I’m worried I named something wrong or I violated some general best practice somewhere 
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Sep 12, 2023 00:39
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Any thoughts on the Rigol dho804? I have an ancient lecroy 9310a but it's the size of a carry on suitcase and has some developing faults so I'm thinking of just getting something hobbyist grade. Use case will primarily be vintage computer "repair" and tinkering and maybe some hobbyist esp32/arduino stuff. The protocol decoding feels really appealing to me for some reason. I'm almost certain that the 70mhz model is fine for what I need and knowing Rigol it'll probably be unlockable to 100mhz variant through software. It's probably way overkill but every time I pull out the lecroy I find myself wishing for something smaller and more modern and I guess right now I'm in the position to pull the trigger. Don't think I've ever really needed a logic analyzer or arbitrary waveform generator so no real desire to step up to the 900. In all honesty I could probably get away with a crappy USB scope for all my use cases but I'd rather not have to tether off a laptop.
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Sep 25, 2023 13:22
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oh yeah I always forget he probably has something to say about osc's. Thanks, I'll go through that! e: Pulled the trigger but they're two weeks backordered into Canada. I'll make do until then 
some kinda jackal fucked around with this message at 20:56 on Sep 25, 2023 |
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Sep 25, 2023 17:23
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I ended up upgrading my DHO800 order to a DHO914 just in case I ever decide I want or need a logic analyzer in the future, AND they pushed back my 800 order a few weeks while they had some 900s coming in sooner, from what I'm told. The price difference wasn't ridiculous, though my impulse upgrade was really only facilitated by the fact that someone is cloning a DIY Rigol's logic analyzer pod for the DHO900s because the OEM one is like $500 on top of the $700-something (CDN funbucks) for the base scope which seems like a LOT for a breakout PCB connected to a bunch of leads but what do I know.
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Oct 10, 2023 16:28
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Nah I hear you. This is definitely one of those cases where I had the spare cash and figured I'd kill two birds with one stone (availability, and a potential LA if I ever need it) without too much hassle. I predict that the 4 channels + decoder will be 100% satisfactory for my needs in perpetuity, but the probe PCB will be a fun-ish build and on the off chance I want to do a trace with more probes in 20 years I'll be all  , ignoring that the price difference would have paid for a more versatile analyzer. But yeah so when I say kill two birds with one stone I suppose I really mean "I'll get my scope sooner" and the other bird not only hasn't hatched yet, but hasn't been conceived. Impulse buy
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Oct 10, 2023 18:48
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I have a PCB I want to design which is 15x10cm, has mounting holes spaced 81mm on X and 122mm on Y based on measurements I took of the destination existing mounting standoffs. I'm struggling to figure out the best way to precisely position these on my PCB. I have leeway for exactly where on the PCB these are positioned, but with reference to each other, the four screw holes have to be at (X,Y), (X+81,Y), (X, Y-122), (X+81, Y-122). If this were a trad CAD program I could probably do this fairly easily just offsetting the first screw hole from board edge 0,0 then offsetting the next +81mm from first's midpoint, etc. Here I'm sort of struggling to figure out what my workflow should be, or if those kinds of tools work I just haven't managed to find them. At first I tried the "place origin point" tool on the (0,0) of my edge cuts rectangle but footprint placement doesn't seem to reference from that origin unless I'm doing something wrong. Then I moved my board to 0,0 and just started adding footprints and manually editing their x,y but I'm sort of getting lost in the math after the first trying to keep them fairly centered on the board (which is a solvable problem, if this is the way to go) and to making sure the holes are exactly where I need them. I think I may have articulated the problem horribly but hopefully you can gleam what I'm trying to do. e: For the record I've played around with both just creating circles on my edge cuts layer and adding a specific mounting hole footprint which is probably the way to go. So I guess the question that REALLY brings up is, can I place a footprint with specific x,y reference to another? e2: Literally 30 seconds after I posted this I found "right click -> positioning tools -> position relative to" some kinda jackal fucked around with this message at 18:08 on Oct 12, 2023 |
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Oct 12, 2023 18:00
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Shame Boy posted:You sure you're placing the grid origin and not the drill origin or something else? Cuz placing the grid origin always works for me exactly like you'd expect... Probably the drill origin, I honestly just expected the drill origin and grid origin to be the same for some reason. e: Yep "place origin for drill files and component placement files". I didn't realize you could select grid origin off the same icon. That's super useful to know, thanks!! e2: OK something's not working, I'm selecting grid origin and the top of my rect but somehow I'm still not seeing that as 0,0. I'll figure this out though, guessing I'm just doing something wrong. I think I have my workflow to finish set! e3: Yeah, changed origin from page to grid origin in preferences and I'm good. This is what happens when you learn just enough of a tool to be dangerous to yourself 
some kinda jackal fucked around with this message at 18:52 on Oct 12, 2023 |
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Oct 12, 2023 18:10
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It's all good! You got me to investigate which led me to the answer. Perfect setup for a dunk.
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Oct 12, 2023 21:15
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Hi ok, this is one of those project posts where I realize I'm making a lot of mistakes, and I'm embarrassed by the output, but if I don't solicit feedback I'll never learn. What I'm posting isn't in any way representative of "ok here's what I have and I'm ready to send it for production", but more of a "here's where I am, and I'm making a LOT of mistakes, but I need feedback to get better" Here is the contextual goal of the project: I have a retro PC, a NABU, which has a PSU I am looking to swap for a Mean Well equivalent. I have the option of simply dropping in the Mean Well and wiring everything directly to it, but I decided to use the opportunity to learn a little KiCad. Other people have done this by simply hacking up the OEM wiring harness and wiring it directly to the PSU, or creating a little breakout board to only translate the PSU to the OEM harness. My primary success criteria: 1. It mechanically supports the Mean Well PSU on the standoffs which housed the original PSU, since there is no "good" way to mount it. Only one of the PSU's mounting holes lines up with the OEM standoffs. 2. It acts as a "distribution board" for the Mean Well, taking AC in from the mains and power switch, routing it to a header near the Mean Well. And similarly taking the PSU output and routing it to a header for the OEM NABU wiring harness. 3. Provide a 5v fan header for a replacement DC fan. My secondary success criteria which influenced some of the design choices I made in my head: 1. Be as "drop in" as possible, require as little cutting of the original wiring as I can get away with. Right now the only wiring modification I think I need to make this work is the power button routing. ... actually since my secondary criteria are driving a LOT of my decision I'm not sure it's fair to even call them secondary, but I guess here we are. --- The schematic I mocked up is this:  I made the conscious decision to take AC and route it on the PCB rather than wire directly to the Mean Well PSU. I don't have a strong reason for doing this other than I wanted the PSU to feed into and out of the PCB rather than be wired to mains directly, just for consistency. Everything else is fairly straightforward, I think. --- The PCB I have mocked up is roughly this (pcb extends past screenshot but no components exist there):   - PCB is 18cm x 10cm and the two mounting holes near the right edge of screenshot is meant to bolt the PSU chassis to the PCB mechanically, no other purpose. - The screw terminal takes earth and neutral as direct inputs and live is routed through the existing fuse on the metal case, through a power switch, and the output of the switch feeds into the remaining screw terminal. - The PSU_AC and PSU_DC footprints are located by hand where they are because they roughly line up in front of the PSU's AC input and DC output. A (very) small wiring harness will extend from the PSU and connect to both headers respectively. - I am 100% certain that I am using the wrong footprint for PSU_AC. My gut tells me that a 2.5mm pitch molex connector isn't appropriate for 120v mains, but I haven't yet figured out how to choose something more appropriate without randomly going through KiCad's library. - I am 100% certain that the autorouting is inappropriate for mains AC but I don't yet know how to properly configure parameters to create appropriate traces. So yeah, That's my ugly baby. At this point I think I'm looking for feedback on my approach of routing AC on the PCB, but I also don't know what I don't know, so I'm very wiling to hear other feedback which I'm certain is necessary. - Routing mains AC on the PCB vs directly wiring the mains cable/power switch to the PSU. Is this just a stupid idea for a beginner to mess with? I don't mind just wiring directly to the PSU, I was just trying to be consistent in my "everything connects to the PCB" approach. - Choosing an appropriate connector and wiring gauge for mains AC to PSU. I also didn't really put a lot of thought into how this is grounded other than the wiring block does connect to mains earth and passes that on to the PSU. I'm not sure what other considerations I should be making here. And apologies, not sure if there's a better way to get screenshots or files out of KiCad. Very much a learning process for me. some kinda jackal fucked around with this message at 17:18 on Oct 16, 2023 |
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Oct 16, 2023 17:13
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DHO914 showed up today. Compared to my old LeCroy 9310A it's almost TOO nice. Not a massive fan of the touch UI and small questionable UI elements but what else would you expect in the year 2023 on an android-based device? Waveform refresh is super fast. I have memories of waveform updates being sluggish on software scopes and old old LCD based DSOs but that's a thing of the past I guess. Really happy with this device whose capabilities I'll use, generously, 5% of.
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Oct 19, 2023 12:13
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Ne Cede Malis posted:I would not use a screw terminal to terminate a stripped AC power cord. The risk of one of the wires slipping out is just too high. {edit} The industry term for such a cable is a "suicide cable" btw. Hey, so it doesn't go unsaid, thank you for the feedback -- definitely taking all the safety info into consideration, and it's good to know I'm not far off base in some of my assumptions. Work got in the way of any hobby stuff these past few weeks but I'm going to try to finish this in the upcoming week so appreciate the feedback.
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Nov 1, 2023 13:33
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I have a quick question. I rescued an old Agilent DSO1012A from the e-waste and it presents no power symptoms. I pulled it apart and the switching power supply is a discrete board. My plan was to start poking around to see what the state of that thing is, in a "baby's first crack at a PSU diagnosis" kind of way. What is the general guidance around energizing a power supply with no load? At this point I think I'm just trying to trace to see if there's anything super obviously faulty. I can do a few things before energizing it such as checking fuses (the obvious fuses check out fine), but at some point I guess the next step is to actually feed it 120 and see what is outputting what. Should I be connecting the actual scope in service of this? I really only ask because it's fairly compact and the wires are all short so it would be a bit awkward. But at the same time I'm not sure if there's a scenario where I try to diagnose the PSU and it's just obviously not working because it has no load or something. Not certain that I articulated that question right but hopefully it makes some sense. I'm trying to do everything I can before energizing simply because it's my first time actually working on a PSU so I'm being very cognizant of not zapping myself, or worse, without being overly paranoid. Healthy fear, is that the term? At some point if it's not super obvious I'll see if I can make an effortpost and ask for advice on the actual repair.
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Dec 15, 2023 15:23
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DC was the one who wore the school uniform on stage right? I forget which one AC was.
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Dec 16, 2023 00:45
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TIL that a commodity 3.3v OLED display doesn't like being hooked to 5v. Well, actually I learned to check the specs for a component instead of assuming it's 5v tolerant. Ideally before you try to troubleshoot why it isn't working. RIP.
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Mar 8, 2024 15:44
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I have a shower thought project that I'd like some advice on. The context is that I have an old typewriter on which I'd like to make the carriage position indicator more visible. My Selectric III has a lit position scale which consists of some 70s plexiglass material side-lit by a neon lamp. The carriage itself has a red and white plastic indicator, but the indicator is barely visible through the scale, likely due to age and yellowing.  I've adjusted it so it's a little more visible than the above photo, but far from ideal. My shower thought project is to 3D print a translucent replacement for the carrier index pointer and backlight it with an SMD LED glued or inset into the back of the pointer, then run the power wires tied to a cable which already follows the carrier from beneath the keyboard so it doesn't get tangled in the moving machinery. The printing part is easy and I can knock that out in 30 minutes. The only catch is that while the typewriter is electric, it's not electronic. The only power source I have available to me is 120 mains right to the motor and neon bulbs lighting the margin. I'm trying to think of a good method of getting an appropriate DC power source inside this machine and honestly my brute force approach would just be to tap the mains off the machine's power switch to the motor to a cannibalized voltage-appropriate AC/DC wall wart with the right resistors in place. I guess this is less an electronics theory question and more a "is there anything obvious I'm missing" question. I haven't seen any appropriate garbage amazon PSU breadboard-project PCBs which will step down 110v to anything appropriate, they tend to be DC-DC step-downs, and I don't really want to go buy a Mean Well just for this. I have a fair amount of room to work with in the case so I could throw the right wall wart in there somewhere without too much effort, but if I can make it compact with some small converter I hadn't considered then all the better. I think the space limitation on the carriage or pointer precludes me from just buying an under-desk LED kit and cutting it down to just one LED, but I suppose I could jury-rig one of those kits to power a single LED in the way I'm thinking? My side-shower thoughts project would be to see if there's any benefit in replacing the neon bulbs lighting the scale with a pair of white LEDs running off the same supply but one thing at a time. e: As I'm thinking through it though, I might be able to just cannibalize one of those dollar store string lights. Same question about powering it but that would be more off-the-shelf with just a little bit of hacking. some kinda jackal fucked around with this message at 13:09 on Mar 14, 2024 |
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Mar 14, 2024 12:48
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I like the idea, that area is just really tight and I’m not certain I could fit a neon lamp in there, unless they’re way smaller than I’m thinking. I do think it’s worth looking into though. E: And to be clear, there is no pre-existing lighting of the carriage indicator, it’s entirely unlit so I’d be adding net-new backlighting through a translucent 3D print, or trying to fit some front-facing lighting if possible (but also facing a lot of clearance issues) I’m out of town for a few days but when I get back I’ll take a quick snap to show you guys my clearance options. Not killing any ideas though Thanks!
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Mar 14, 2024 17:09
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Not production quality, but conceptually should I be able to sniff a CAN bus by just inserting oscilloscope probes into a connector with CAN-H and CAN-L traffic? I'm tapping the CAN-H/L pins on a device on my bike with two needles jammed into the connector and I see the differential signals on my DHO914 but for the life of me I can't get it to either trigger on, or decode the CAN packets and I can't figure out why. Voltage is what I'd expect with high and low base ~2.5v referenced to ground. I guess there's two scenarios here assuming I haven't just hosed up something super basic on the scope. My needle tap is way too janky to be reliable, or the DHO is buggy. I've never tried a CAN snoop before on this (or any) scope, but I haven't really hard any reports of the DHO's not playing nice with CAN. I guess a third option is that I somehow tapped into entirely the wrong thing and am getting a valid differential signal pair that isn't CAN but I doubt it. This is the same socket that aftermarket CAN bus accessory controllers plug into on my bike. I'll do up a video later after work and maybe someone can just check my math visually in case I'm missing something supremely obvious. I don't have ready access to another CAN source that I can easily try. I mean I could try my car but I don't feel like pulling panels or digging to see if my ODB port exposes CAN. I do have some CAN breakout transceivers that I can hook to a spare ESP so I might try just generating some traffic to see if the scope plays well with that or not. some kinda jackal fucked around with this message at 11:49 on Mar 20, 2024 |
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Mar 20, 2024 11:46
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My guess is that CAN triggering takes the frames into account because then yeah, I agree, I'm not sure how else it would differ from edge triggering. Basically this, but on a newer scope: https://www.youtube.com/watch?v=METmiiieV6Y And yeah, I fully agree. This was just me being excited to finally have a scope that can do decoding and leaving the exercise scratching my head. If I decide to do anything with the CAN messages for real I'll be doing it with an ESP and transceiver board, I just hadn't gone to the trouble of moving my breadboard setup to the cold garage and stringing wires around
some kinda jackal fucked around with this message at 17:01 on Mar 20, 2024 |
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Mar 20, 2024 16:57
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espp32
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Mar 27, 2024 20:44
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Hey I have a battery question. If I have the specs of a battery (3.7vdc, 850mah/3.15wh, lipo), is that enough information to determine battery compatibility? Have a device on which the battery is on its way out. 30 min or less of charge. It's soldered to the board but really easy to replace so I'm not actually worried about the physical act of replacing it.. Batteries which are marketed as "for" this device have a lead time of 2+ weeks to deliver off amazon or ebay, but I can get a different battery with compatible dimensions and SEEMINGLY compatible specs (3.7vdc, 900mah, lipo) for a competing device overnighted. Is there anything I need to consider before just giving it a shot? Like both batteries look fairly simple with just a red/black lead to attach to their respective devices, so I don't think there's any device specific electronics in play. In my mind this should be a simple swap, but as with everything in this space I'm very wary of nuance that I don't really understand. For reference here is the actual battery: https://www.amazon.ca/dp/B0B1TPTFG7 and just as I'm typing this I noticed the replacement candidate doesn't actually fit dimensionally for height (8mm vs 6mm, let's assume that's not going to fit) but let's just pretend I did find a dimensionally compatible battery for my own curiosity. some kinda jackal fucked around with this message at 11:54 on Apr 2, 2024 |
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Apr 2, 2024 11:51
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Oh yeah, that's absolutely on my radar, thank you. Whatever I source I'm going to try to add a tiny connector on both ends so I don't have cables flopping all over the place.
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Apr 2, 2024 18:36
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I like my Rigol DHO914 but in retrospect I wish I had bought one of the N-1 scopes without a touchscreen interface. Maybe I'm just so used to 20+ years of occasional scope usage that flipping options with a knob doesn't bother me at all, while poking at a screen with a sausage feels clunky. I think with the DHOs being the new "hot" thing I'd see if the N-1 scopes are going on discount. I doubt they're worth turning a nose up at, especially if the DHO is at a 4-500 price point. I went with the 914 strictly because I wanted to future-proof with the ability to use it as a logic analyzer as well, only the OEM probes cost as much as a base DHO itself, and are way way way more expensive than a bespoke USB logic analyzer which would probably be more versatile anyway. There's a handful of DIY probe projects listed on eevblog forums that I'm going to look into, but part of me is just thinking of going the buy-once-cry-once route on the OEM probes. I'd have to hand assemble that DIY solution for probably a hundred bucks anyway, and would almost certainly botch it at some level. some kinda jackal fucked around with this message at 11:57 on Apr 3, 2024 |
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Apr 3, 2024 01:50
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lmfao holy gently caress how did I go this long without a pair of magnifying goggles for soldering?? It turns out being able to clearly see what you're doing makes soldering much easier. Controversial take, I know.
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Apr 4, 2024 00:33
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This is the year my eyes started to go and I've been low key crushed by it. I finally decided soldering a lipo battery to a board without shorting something and setting my house on fire was a bridge too far and bit the bullet. Literally wish I'd done this years ago even if I didn't need it.
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Apr 4, 2024 02:47
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eBay finally delivered the weird connector I needed to create a canbus splice for my motorcycle but I've got a very rudimentary understanding of canbus termination requirements. This arguably speaks to "you don't understand canbus so please don't monkey with your vehicle's central nervous system until you do" and I'm very cognizant of that, which is why everything I'm doing right now is designed to be removable when I'm actually riding the bike. Anyway, I effectively bought the connector required to plug into my bike's tire pressure monitoring system canbus signal, so my intent is to create a Y fork and provide canH and canL to a split off connector that I can use to either probe, or to eventually hook up an esp32+can interface to READ data. The new offshoot twisted pair will be fairly short, maybe a few inches at most.  My question is about termination requirements when I'm just using the new offshoot connector for probing with a DSO or LA. I guess I just don't understand the requirement, actually. Ideally this is a cable I can keep in place even while nothing is hooked up, at which point I presume I WOULD need to terminate it? What would be the potential effect of just leaving the connector unterminated while it's not being used? I have a sinking feeling that this is a super basic question with a really obvious answer but somehow I'm just not putting two and two together. I'll take my lumps but I'm thankful for any thoughts here. My end goal is to install an esp32 that can send basic bluetooth HID to my phone based on the canbus messages from the scroll wheel on my motorcycle's handlebar which is effectively useless without BMW's own proprietary GPS unit on my older bike. The messages are all documented by enthusiasts, I'm just trying to figure out the connection now without making a mess of my bike.
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May 1, 2024 14:24
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A+, thank you. Yes, I was worried about terminating with resistor. Totally forgot about the unterminated diag port. Thanks!
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May 1, 2024 16:15
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