Beginner Electronics/Repair Lab - Page 1
Forum section: electronics / beginners

author: joowon
author_rank: Contributor
timestamp: August 22, 2024, 02:11:49 am
content: Hi this is my first post here! I'm looking to go to college for ee and am interested in trying out some board repairs right now so I'd appreciate any thoughts or advice of anything I should have now or in the future. Projects I probably want to do in the future are some random hardware reverse engineering of something like wacom tablets and video related stuff. But for now I want to go through some books, some of the things I bought to make doing lab exercises easier/possible.Prices I italicized are for things I haven't bought yet.Multimeter-https://www.amazon.com/gp/product/B07N2GG5L4/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1= $30shitty "true rms" meter that I saw northwestrepair on youtube use that seems to do the job, I'm probably going to be using scope most of the time for prototyping, so I just want the extra features that multimeters have.Oscilloscope- Siglent SDS 804X HD = $430DHO800 samples less for the same price and I don't think goes down the used route/clearance route of a ds1054z is worth it ($239?) when i can get "double" the performance and 12bit for a better price to performanceSoldering Iron- Pinecil + tips = $50I already bought this and I don't need anything better, I see most people only need powerful consistent soldering irons for wicking in consumer electronics stuff although i'll probably eat my words when I go see anything outside of gpus and phonesHot Air Station- Atten 862D = $170Don't think there is anything better in the $100-$200 price rangePreheating Plate- 946C = $43Rebranded like hell in the market, but I don't think I'll be doing full BGA gpu core reballing or CPU socket replacements anytime soon, so this is adequate for my usePower Supply- random chinese 30V 10A (https://www.aliexpress.us/item/3256806822122116.html) = $43I wanted to get a used agilent 6643A or something, but used market on ebay seems kinda bad rn so I just picked this up since someone else in a discord said it was okay (but it's still chinese crap :p)Waveform Gen- FY-2300 = $50Honestly don't need it for my use case, but lab exercises ask for it. I was looking at DIYing it, but it really doesn't make sense when I can just pick something up for cheap. Maybe I can make one as a project or something later on.Fume Extractor- VEVOR 150W = $230I don't want cancer.Solder Wire- Kester 63/37 .015 diameter 2.2% flux = $50I see people saying quality solder actually helps so I'll try it outSolder Flux- TCRS (when it comes back in stock) =$30Already got some chipquik, but I see this being recommended and it's by a repair guy so I wanna try it out for SMD and BGASolder Wick-https://www.aliexpress.us/item/3256805951895606.html= $10I'll go gamble if it's good wick or bad wick lolMicroscope- Eakins 3.5x-45x (AmScope SM-4 copy?) = $350I don't think there's a point of buying a shittier microscope and replacing it with a better one later, so I'll get the thing that'll hopefully be the end all be allrandom repair stuff:Reball Jig-https://www.aliexpress.us/item/3256803549266793.html= $35Solder Balls 0.4, 0.45= $20Kapton + Aluminum Tape= $20Random Tools (tweezers, screwdrivers, etc)= $30Stencils= $5UV Light and Mask= $10FPGA Dev Board(?) - $80I wanted to get into FPGA, but honestly as a beginner hobbyist, mcus do everything and I'm excited for that new rp2350 and pico 2 (https://dmitry.gr/?r=06.%20Thoughts&proj=11.%20RP2350). I'm thinking of designing my own board and soldering on my own artix-7 chip or something.Not going to include random components because aliexpress links will expire after like 2 seconds. Mainly wanted to post this so others could see a list of some equipment if they search forums or google and whatnot. Thanks!

author: squadchannel
author_rank: Frequent Contributor
timestamp: August 22, 2024, 02:32:53 am
content: solder wick buy a good brand. The Chinese ones are shit that absorb at all.The same goes for solder. chinese ones, it is recycled and disintegrates into a ragged crumble when you try to melt it. It does not melt at all.

author: joowon
author_rank: Contributor
timestamp: August 22, 2024, 02:40:40 am
content: normally I'd agree but honestly wanted to just try it out since I've seen other people use this brand just fine and if I can buy 10pc of it really cheap, it'll save me money for when I get more. If it isnt good, not that big of a deali go to digikey in 2 seconds

author: jasonquin
author_rank: Contributor
timestamp: August 22, 2024, 05:22:03 am
content: If you are going to do some board repair or reverse engineering, you need a proper DMM with good continuity test performance.Also, don't waste money on Chinese soldering tools, I as a Chinese engineer have never trusted those crap, get a made in Taiwan/Japan/USA brand.

author: seedkey
author_rank: Contributor
timestamp: August 22, 2024, 05:29:30 am
content: Your solder choice is great. Kester 44

author: Smokey
author_rank: Super Contributor
timestamp: August 22, 2024, 08:04:18 am
content: Quote from: squadchannel on August 22, 2024, 02:32:53 amSolder wick that won't wick usually has all the flux dried out.Get some good tacky flux and that usually fixes the wick.https://www.digikey.com/en/products/detail/sra-soldering-products/TF5000/10709784

author: wasedadoc
author_rank: Super Contributor
timestamp: August 22, 2024, 09:17:25 am
content: Nothing wrong with high ultimate ambition but trying to run before you can crawl would be my comment. Have you even soldered a $10 beginner kit before now?You can learn a lot with a $10 meter, a $40 iron and working on battery powered circuits.Yes it is nice to have a complete suite of gear when you start but it is often the case that you think more when you don't have the ideal piece of equipment to do something and are forced to use a different technique with what you do have.

author: Smokey
author_rank: Super Contributor
timestamp: August 22, 2024, 09:49:15 am
content: Quote from: wasedadoc on August 22, 2024, 09:17:25 am... I'm not sure I agree with that....I'm thinking of a time way back in the day when I was in school. I was making a thing that talked over a 433MHz radio data link and I just could not get the damn thing to work reliably. I wasted a TON of time doing all manners of ineffective troubleshooting before I just bit the bullet and got a logic analyzer and that showed me the problem in about 5 minutes....The thing I learned from that was to go straight to the right tool for the job and use that tool to solve your problem and then move on.

author: wasedadoc
author_rank: Super Contributor
timestamp: August 22, 2024, 10:42:41 am
content: Quote from: Smokey on August 22, 2024, 09:49:15 amBut was that your first, or even very early, electronic project?

author: joowon
author_rank: Contributor
timestamp: August 22, 2024, 10:48:05 am
content: I've made my own DIY projects and spent way too much time doing SMD with no microscope and decided I want to actually do stuff properly. If I don't mind asking what exactly are some of the stuff you disagree with on my list?I already have a pinecil which is great for not crazy pcbs and I did get the shittest multimeter with features haha (I had a crap $10 one before). The repair stuff such as fume extractor, hot air, and microscope are pretty much necessary if I wanna go step inside bga rework. The scope is the only thing I'm asking myself if I'm spending too much money, but I think I'll justify the purpose when I don't buy anything else for a longggg time

author: wasedadoc
author_rank: Super Contributor
timestamp: August 22, 2024, 10:53:51 am
content: Quote from: joowon on August 22, 2024, 10:48:05 amSo you are NOT a beginner.

author: joowon
author_rank: Contributor
timestamp: August 22, 2024, 10:59:34 am
content: I still classify myself as such, I haven't design anything (that isn't super basic on a breadboard), but I did wanna put it in the title to signify I am new to test gear and haven't touched an oscilloscope or function gen. And I did want to put this post up for others wondering about what to buy as well.

author: joowon
author_rank: Contributor
timestamp: August 22, 2024, 11:29:55 am
content: Quote from: jasonquin on August 22, 2024, 05:22:03 amoh yes for sure I am staying away from those aixun nasty voltage leaking tips. I want to get a hakko 951, but they seem to be counterfeited pretty often so I'll figure that out later if I need more power.

author: RogerG
author_rank: Regular Contributor
timestamp: August 22, 2024, 11:44:56 am
content: QuoteDon't do that. These PSUs are of switching type, they have plenty of harmonics and can produce unwanted effects in your circuits. The adjustment of voltage and current with coarse and fine regulators can be a real pain. My recommendation would be to go for a proper linear regulated PSU, for example a Korad KD3005D. Output is clean, adjustment works great and they don't cost so much more. It's easy to repair, too.

author: joowon
author_rank: Contributor
timestamp: August 22, 2024, 11:49:38 am
content: Quote from: RogerG on August 22, 2024, 11:44:56 amyes it's probably a piece of shit, but I want 10A to be able to see shorts easily for repair. if I dive into some low noise stuff I'll go for a used agilent or something.

author: armandine2
author_rank: Frequent Contributor
timestamp: August 22, 2024, 12:08:58 pm
content: Quote from: joowon on August 22, 2024, 02:11:49 amI agree on the microscope ethos - a good view is a game changer.Not sure how much space you need for your fume extractor - I've been thinking about a Weller ZeroSmog table top device

author: joowon
author_rank: Contributor
timestamp: August 22, 2024, 12:24:53 pm
content: Quote from: armandine2 on August 22, 2024, 12:08:58 pmAmerican ebay got thesehttps://www.ebay.com/itm/125453546398.I've been blowing a fan out my window but I think it's time I actually start caring more about safety if I'm spending this much money.

author: BILLPOD
author_rank: Frequent Contributor
timestamp: August 22, 2024, 12:52:05 pm
content: Good Morning Joowon, and welcome to the forum, I got a lot of my test gear for the same reason as you. When I was taking electronics classes, the labs were crowded, so doing the exercises in the school lab wasn't giving me much hands-on time with the equipment. I then bought myself an o-scope, which was big bucks back then. I also pieced together the components from Radio Shack, (no internet back then), and eventually I was able to do the experiments at home and spend as much time as necessary to completely understand what all the experiments wereabout. Good luck with your studies, and you will find lots of help on this forum that has many very sharp minds.

author: tooki
author_rank: Super Contributor
timestamp: August 22, 2024, 02:02:06 pm
content: Quote from: joowon on August 22, 2024, 02:11:49 amSolder wire:Get Kester 44, 63/37, but 3.3% flux (Kester core size 66), and I would rethink the size. 0.015” is quite thin. As everyday solder, I recommend 0.02” to 0.032” (0.5-0.8mm). I do have 0.015”, but I rarely need it.What about solder paste? I would get some, too. E.g. ChipQuik SMD291AX 63/37.Flux:The TCRS flux looks to be unactivated rosin, so it won’t be an especially active flux. Which ChipQuik do you have now?Solder wick:Don’t dick around with cheap junk, not when quality stuff is only a few $. I have been very happy with MG Chemicals wick, but they changed their supplier (country of manufacture changed from USA to Japan) and while I assume it’s still excellent, I haven’t used the Japanese product. But any name brand (Chemtronics, MG, Menda/Easybraid, etc) is going to be fine. I like that Menda lists the actual stranding. Chemtronics and Spirig (Swiss brand) tend to use slightly coarser stranding than I like.FYI, with solder wick, the two things that determine quality are the stranding and the flux. The flux is where el-cheapo wicks often fail, and end up forcing you to add flux yourself for them to work.

author: joowon
author_rank: Contributor
timestamp: August 22, 2024, 02:19:22 pm
content: Quote from: tooki on August 22, 2024, 02:02:06 pmFlux: Chipquik NC191. This is the one I want to get as amtech 559 is bunch of fake shit right now,https://www.tcrscircuit.com/product/759-asx-gen-2-high-performance-no-clean-tacky-flux-30cc-syringe/24?cp=true&sa=true&sbp=false&q=false.Solder Wire: I think I'll use 0.015 because it'll be useful for small GPU bga pads, 3.3% is like $10 more for some reason so I'll just save my bucks there.Wick: I used the MG-chemicals one and it was kind of junk tbh (maybe just needed more flux), but yes I'll buy the easybraid if this one is junk, just wanted to try it out because others had good experiences.Solder Paste: I don't want to refrigerate paste and clean off paste everytime on stencils, I can just use my jig and dump balls.

author: ledtester
author_rank: Super Contributor
timestamp: August 22, 2024, 04:20:25 pm
content: I would initially pass on the cheap 30V/10A power supply.For lab circuits you generally don't need a lot of power but you really want to have clean power. And having multiple rails is very helpful. For most of my breadboard circuits I've gotten by with a dual 24V/1A linear power supply.

author: joowon
author_rank: Contributor
timestamp: August 22, 2024, 04:24:48 pm
content: Quote from: ledtester on August 22, 2024, 04:20:25 pmyes I only got it because I want to see shorts easier with iso alcohol/thermal cam. Ill probably pickup a used linear agilent power supply later on if I need it.

author: tooki
author_rank: Super Contributor
timestamp: August 22, 2024, 09:19:02 pm
content: Quote from: joowon on August 22, 2024, 02:19:22 pmI don’t care for NC191, it has only a very short activity duration. SMD291NL is what I like best (of the ChipQuik fluxes I’ve tried so far).I wouldn’t want an unactivated rosin flux.I very much doubt any MG solder wick is “junk”. Extra flux never hurts, but proper technique (large, clean tip, and enough solder added to provide good thermal bridging) is essential, too.Choosing a lower-flux-% core on very thin solder wire is a bad idea. It will be ok for most solder joints, but the thing to remember is that solder wire is also part of the maintenance supplies for your soldering iron! Successful soldering requires regularly tinning your tip with solder, and flux is critical. With thin solder wire, it gets hard to feed in solder fast enough to easily tin your tip. So thin wire is precisely where the larger flux core is extra desirable.Alternatively, get your 2.2% thin wire, but also get a thicker wire for tip care. (At work, there is tons of old stock of huge 1.5mm and 2mm thick solder that is far too large for anything I need to solder, but which I use for tinning, because it makes it easy to flood the tip with solder to flush away “overcooked” solder on the tip.)BGA balls are for reballing BGAs. You still need solder paste for other things. Stencil cleaning is unavoidable when using a stencil, but also isn’t difficult to do. Solder paste is also useful without stencils. You can get room-temperature-stable solder pastes now, by the way.

author: tooki
author_rank: Super Contributor
timestamp: August 22, 2024, 09:21:39 pm
content: Quote from: joowon on August 22, 2024, 04:24:48 pmRunning huge amounts of current through a thing is a great way to break it even more. It’s not an approach I’ve seen professional electronics technicians do on purpose, and it’s not a technique that is taught as such. On the contrary, you use a current-limited supply so that you limit the current through a short. It doesn’t take much to see the difference on a thermal camera.

author: joowon
author_rank: Contributor
timestamp: August 22, 2024, 10:09:53 pm
content: Quote from: tooki on August 22, 2024, 09:21:39 pmobviously injecting voltage into a sensitive component such as gpu cores is a really bad idea, but i can power gpus without putting it inside PCIE slot to find shorts easier on whatever power rail. I'm not going over the maximum recommended, quite under actually! I think there are some mods out there that even use a pcie riser to just power the necessary slots to see if there's fan spin etc. without risking killing my test bench or something dumb, so that's something I want to buildQuote from: tooki on August 22, 2024, 09:19:02 pmmight pickup some of that chip-quik for now! i haven't tried enough fluxes or know the chemical aspects of flux, so I don't know how rosin-activated/deactivated with affect cleaning, activity duration, and whatnot. i'll probably try out a bunch of different fluxes in the future.for wicking did i get a larger tip that might help my pinecil actually supply the heat I want so maybe it was my fault.you do make a good point of higher flux % on thinner wire, I already ordered it but that is something I'll keep in mind for next time.I will probably order some higher diameter for tip life, once I get off the chinese pinecil tips (maybe I'll do the 3d print thing to make hakko tips compatible instead).I really don't see where I need solder paste for anything right now and from what I remember that stuff does have an expiration, did not know there was stuff you didn't have to refridgerate! will keep in mind if I want to do some lazy smd stuff and cook it in an oven, a proper pcb one I promise.thanks a lot for replying and helping me!

author: seedkey
author_rank: Contributor
timestamp: August 24, 2024, 05:45:21 am
content: Took gives you good advice on the larger solder for tip cleaning.I would get Kester 186 RMA Flux

author: PinheadBE
author_rank: Regular Contributor
timestamp: May 13, 2025, 01:46:33 pm
content: Quote from: joowon on August 22, 2024, 02:11:49 amHave you (or anyone else) figured out the meaning of the parameters in the menu?