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Posted by u/juanse 3 months ago
Ask HN: How do I learn practical electronic repair?
In my country, 2 decades ago there are were plenty of people who knew the basics. Today, it feels like a lost art.

I would like to approach it as a hobby, not like electronic engineer level, but enough to debug problem and change components to a low level.

What is the pragmatic approach in this mission? I reckon it will be valuable in the future that comes.

atonse · 3 months ago
Louis Rossmann’s electronics guide was the first time these concepts truly clicked for me: https://youtube.com/playlist?list=PLkVbIsAWN2ltOWmriIdOc5Cti...

Apart from that, just fix broken stuff. Practice like any other skill, like others have said.

Like decide what skills to learn based on what’s broken.

Need to solder something together? Buy the soldering iron. Need to figure out which capacitor you need to replace with? Learn how to identify capacitors and navigate digikey.com

hyperman1 · 3 months ago
I'd add: Learn to recognize dangers first. From the top of my head:

* big caps that can contain high voltages even when a device is powered off, in TVs or microwaves.

* Know where a fire extinguisher etc is, keep them near the workbench.

* Keep the workbench clean, tidy and well-vented.

* Don't panic when mistakes are made. Slow down instead of doing a quick-fix.

* I like a big red button to power down everything instantly. Can be just a switch on a plug box.

Nextgrid · 3 months ago
If you're often working with mains-voltage things, you can use:

* an isolation transformer - meaning you must now touch both conductors to get shocked instead of just the live one

* a foot switch to control the power supply - serves as a "dead man's switch" to cut power in case of an accident

(these are not mutually-exclusive, you can combine them)

ajb · 3 months ago
Definitely

Risks to consider in general are (also of the top of my head don't take as exhaustive):

* Electrocution

* Burning yourself

* Setting stuff on fire

* Fumes, both from soldering and overheating/burning plastic

There's a kind of balance between habits and awareness. Rely too much on awareness and you will miss some safety issue during a complicated repair. You need good habits, but rely too much on them and you won't notice when you finally make a mistake.

Those apply during repair processes. It's also possible to render a device unsafe to use, for example by damaging a li-ion battery or by a 'bodge' repair that circumvents a safety feature.

gregoriol · 3 months ago
Also let someone know where you are and by what time you plan to have completed the job, could save your life
sriram_malhar · 3 months ago
I loved Rossman's explanation of the transistor. Transistor is just a controllable resistor. So simple. No one told me this. I could have saved years!
lsharkey602 · 3 months ago
I'll just say, "thank you".
globalnode · 3 months ago
that playlist actually looks promising, will have a look later.
BigCatStuff · 3 months ago
I believe Youtube videos are a great resource for learning this! I picked up electronics and computer/gpu repair as a hobby over the pandemic lockdowns.

A cheap multimeter and a cheap soldering iron/hot air station combo will get you very far in the hobby. I enjoy these channels:

MyMateVince (a guy who fixes many useful household items): https://www.youtube.com/user/mymatevince

StezStixFix: https://www.youtube.com/@StezStixFix

Electronics Repair School (more advanced, he fixes laptops, tvs, and sometimes gpus): https://www.youtube.com/@electronicsrepairschool

ryandrake · 3 months ago
YouTube videos are great -if- the problem you're having is exactly the same as the problem the YouTuber is solving. For example, I was able to replace the HDMI capacitors on my A/V receiver because I lucked upon a YT video where the problem I was having was identical to the problem the YouTuber was solving. So it was basically, buy these capacitors, replace them, and off you go. Repair usually just requires basic soldering skills and the ability to put things back together you took apart.

When the problem is not exactly the same, I'm just lost. There is not a lot of diagnosis videos on YouTube. All the videos are: "1. I observed this problem. 2. [???] 3. I'll walk you through soldering on the new components." skipping the most important step 2.

Same for car repair videos: "I see Problem X happening. Problem X usually means component Y has failed. Here's how to replace component Y. The end." If that doesn't work, you wasted money on the part and your time ripping apart your car and putting it back together.

BigCatStuff · 3 months ago
I agree that the diagnosis and visual inspection is the most important skill in fixing random items.

In the channels that I suggested, all of them go into the repair not knowing what the fault actually is. They take the viewer through the whole diagnosis, and they (with the exception of Electronics Repair School) are not electronics technicians.

Once a person has seen enough different ways of diagnosing items (by watching videos or hands on trying), then faults in other items become easier to find.

sowbug · 3 months ago
Big Clive, too. https://youtube.com/@bigclivedotcom

He buys cheap crap, takes it apart, and usually infers a schematic. He also admires or critiques the designs. After a while you'll notice patterns.

analog31 · 3 months ago
I repair practically anything that breaks in my house -- except heavy work on the car, or the roof. A few things, from me as a kid:

1. Take things apart, and try to figure out how they work. Don't worry too much about getting them back together. But then, trying to reassemble it is good practice too. There's plenty of old electronic junk that you can explore before throwing it away. Build a mental catalog of how things work and are assembled. Among other things, this will help you when you need to come up with a strategy for getting some particular gadget open -- often 9/10 of the problem.

2. Like others have said, YouTube is great. People will make a video of a repair, or even just getting something open, for a few "likes." Also, most of them are just normal genuine people who aren't trying to be influencers, so it's kind of culturally refreshing. Many of my successful repairs started with YouTube, such as my clothes washer and dryer, refrigerator, lawn mower.

3. Many of my most cherished tools are what I call for "demolition," not electronics specific, like picks, pry bars, a slim knife that can get between things, stuff like that. Another set of cherished tools are my magnifying visor, small magnifying glass, bright flashlight, and a stereo inspection microscope that I got second-hand.

4. A lot of "electronic" failures are actually mechanical in nature, and you can just use your general troubleshooting rundown to figure them out. Switches, connectors, cables, etc.

5. Begin to get the hang of identifying parts, and how part numbering schemes work. It will help you in your search for spares.

6. These days I often ask my spouse for a opinion. She's a laboratory scientist, quite sharp and skeptical. I'll have a hypothesis, and she asks the one question that blows it out of the water.

Good luck! Don't get electrocuted or burn your house down.

exe34 · 3 months ago
> Take things apart, and try to figure out how they work. Don't worry too much about getting them back together. But then, trying to reassemble it is good practice too.

For some reason I got my hands on a lot of old clocks as a child, and after getting the springs out, I never could get them back in. Turns out there's a special lathe you need to use to coil them up tightly enough. Only learnt that when I was about 20.

colechristensen · 3 months ago
Roughly in order

Beginner

* Get a Miniware TS101 USB C soldering iron, some solder, solder wick, flux

* Get a mediocre multimeter

* Do a little soldering assembly kit to learn how to solder, there are some good NASA manuals and videos to learn techniques and you won't need to do as good a job as they do

* Learn how to identify and replace broken capacitors

* Learn how to replace power and USB connectors

* ^ (a huge proportion of things that are fixable at all are going to be those two)

Intermediate

* Learn about static (ESD) safety, get the equipment and supplies to prevent frying things yourself

* Get an arduino or other low cost prototyping board and learn to program it and do little projects

* Find some broken consumer electronics with guides on https://www.ifixit.com/Guide and try to fix them, these things are often less about "electronics" and more about glue

* Read the parts of Zen and the Art of Motorcycle Maintenance about maintaining and fixing things

* Read https://www.eevblog.com and watch https://www.youtube.com/eevblog for information and inspiration

Advanced

* Get an oscilloscope and bench power supply, learn how to probe and analyze signals on boards

* Figure out yourself what next steps to pursue, you should be able to at this point, or at least to ask more specific questions

mikewarot · 3 months ago
I've got a friend who has been at this since learning in TV repair shops in the 1950s. His emphasis is always on fast turn-around. He doesn't believe in slowly turning on things with old electrolytic capacitors, for example. I've learned quite a bit from him.

I've learned not to fear B+, but to give very healthy respect to anything more than 500 volts. (Only use 1 hand, keep the other behind you, always have a safety partner, etc)

I've learned to hate Silver Mica capacitors. I've learned how to track down the bad ones that cause the "crashing" sound in old radios.

I've learned that in very old electronics, you can let smoke out, and things will still work. I've gotten good at seeing where the smoke comes from.

You'll definitely need to learn to solder. I'd suggest starting with something like an Arduino starter kit to get a sense of how components actually interact.

But remember, if something is dead, you can't really make it worse. (Just be careful not to make yourself worse along the way)

vel0city · 3 months ago
> give very healthy respect to anything more than 500 volts

Man, I'd say be very respectful to anything that might be running 120-240V, and be very sure about anything higher than that. Anything <50V can often just be fun tinker whatever assuming you're ok with breaking whatever you're playing with, up to a certain max amperage of your power source. High amperage but low voltage can still cause some serious messups if you don't have the right fuses in place. But I get other voltages are common in Europe.

tuatoru · 3 months ago
DC, definitely. Above 60V is dangerous.

AC, 120V will 'bite', 240V will make you shaky (remembers id10t maneuver yesterday, first in a decade). And burn you. In damp environments or with corrosion around, much worse things can happen.

prpl · 3 months ago
i’ve been hit by 350V trying to bias a tube amp but it was low current (B+). Woke me up
moron4hire · 3 months ago
Nah, 120v ain't so bad. Hurts less than hitting your finger with a hammer.
cowboylowrez · 3 months ago
yeah I just treat any higher voltage like I would a snake, I stay away haha.
steve_adams_86 · 3 months ago
> You'll definitely need to learn to solder.

Probably implied here, but learning to desolder is huge too. And there are tricks to it that didn't come easily to me. When you buy your first iron, I think it's worth getting some flux and solder wick as well. Taking circuits apart cleanly and properly can make repairs so much easier.

baq · 3 months ago
Me the complete soldering newbie was very surprised when he discovered that desoldering is much more difficult than soldering. Getting a blob of tin to conduct is easy, getting the blob of tin out of there… impossible without tools and technique. Obvious in hindsight.
tosmatos · 3 months ago
On that note, is it worth it to get a desoldering iron ? Like, what is essentially a soldering iron and a desoldering pump combined ? I've had little success desoldering in the past, and broke boards because of it.
7402 · 3 months ago
Gosh, you don't need to start with dangerous high voltage tube stuff! There are old transistor electronic devices that was built on circuit boards with nice discrete components. You can practice soldering and unsoldering on an old transistor radio.
kazinator · 3 months ago
To debug electronics effectively, you cannot underestimate how much EE knowledge is needed.

Start with something like The Art of Electronics by Horowitz and Winfield.

An example of the kinds of EE stuff you don't heave to know to be an effective troubleshooter of basic issues, might be, oh, say, what it means for the poles of a transfer function lie in the left half of the s-plane.

bombcar · 3 months ago
As a counter, you can get amazingly far with little to no EE knowledge - depending on your troubleshooting skills and how modular something is.

A stereo that loses the right channel unless you push on the board? Broken solder joint.

Visibly exploded caps? Bad caps.

Some basic understanding of electricity and current flow and the high-level concepts will help, but a detailed education is more for building your own than just repairing existing mass-produced setups.

(As an aside the electrical knowledge in a good ham radio study guide would be a great place to start - https://home.arrl.org/action/Store/Product-Details/productId... )

pyb · 3 months ago
Agree that a foundation in EE is needed, however AoE is not a beginner book.
kazinator · 3 months ago
AoE is probably a good book for that kind of "beginner" who has a degree in a STEM discipline (or in the middle of getting one), but doesn't know electronics.
homieg33 · 3 months ago
Just yesterday I fixed a broken wireless N64 controller receiver with the help of ChatGPT. I tried looking for YouTube videos, but didn’t find the exact thing I needed, and since I’m such a newbie I needed a lot of hand holding.

Anyways, I took pictures of the components and described what I was seeing. It walked me through things really well and asked me to do tests and report back. It even told me how to use my specific multimeter after I took a picture of it. I ended up soldering a jumper cable from the console power supply line (not working) to the micro usb power line (working).

It actually works now and really saved me 30 bucks buying a new controller.

rahimnathwani · 3 months ago
This is fascinating. Would you mind sharing the chat transcript?
lnsru · 3 months ago
The thing is that one needs understanding of an electrical engineer to debug circuits one wants to repair. When you have understanding you can do some voltage measurements and try to identify faulty part. There is gazillion different parts now, that wasn’t the case 2 decades ago.

I know few people who repaired their washing machines just watching youtube videos. No skills and no knowledge. That’s the best error you can find - series error. All the appliances of the same manufacturer built in the 5 years will predictably fail and replacing 20 cent regulator revives the machine.

There are then random faults, that need deep knowledge and hours of debugging. They’re not economically viable to repair unless the machinery is very expensive. Good example is 400€ transistor replacement in €20k Tektronix probe.

Then there are things one shouldn’t touch - Tesla battery packs and open microwave ovens for example. Enough energy to kill or badly injure the unlucky hobbyists (in German): https://www.kosmo.at/tesla-akku-explodiert-mann-schwer-verle...

There are enough analog electronics to repair what requires deep analog design knowledge. Music instruments and radio equipment might fall into this category.

I would say, the repairs make no sense in the future that comes. With more and more electronics and programmable components the repairs are not economically viable. I am designing a motherboard with MPM54304 PMIC and a microprocessor. Both are programmed and without firmware sources and circuit diagram one will not able to recreate desired functionality. After product release I will organize workshop for my colleagues from service department and they will still come to me to discuss the repairs when some early faulty products will be send back by customers.

bombcar · 3 months ago
Washers and dryers are probably one of the best places to start - if you have the ability to bring them home, you can find them laying literally for free.

80% of the problems are a single part or loose connector, and they’re big enough and common enough that they’re easy to work on and have lots of YouTube help available.

Then you can progress to working on the control boards themselves instead of just swapping them.

If you have a garage and will do this, I highly recommend the harbor freight lift table: https://www.harborfreight.com/500-lb-capacity-hydraulic-tabl...

Once you get into it you can actually make some coin, free washer, $10-50 in parts, sell for $100 when working.