Electronics Repair Megathread

I don’t know if anyone is interested in this and/or if this is a good idea, but maybe this thing could become a thing.

I regularly repair electronics, so I thought I might share some of the things I work on and encourage others to do the same. The main idea of this thread is to have a place for people to share their repair related adventures and to ask for help if they get stuck or want to learn some basic repair skills. For general discussion regarding right to repair, have look at this:

Right 2 Repair Corner

With that out of the way, let the fixening commence!

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The first question is: What tools to get to repair electronics? I kinda have a Buy It For Life mentality but I dont know how much to spend or rather what is the reasonable price ceiling should I aim for to avoid overspending. My way forward is that I buy a generically branded (probably terrible) Stanley or go cheaper if I know it will be used less over time.

The specific brands to get will depend on what you are mostly dealing with, especially with a buy it for life mentality. Somethings just be consumables.

With that said, helping hands, an ESD mat, tweezers, soldering iron, good solder, solder sucker/wick, flux, magnifying glass, and good lighting are a good start.

once you are confident with that stuff, then you can upgrade to a bench power supply, oscilloscope, heatgun/reflow setup.

What is the deal with cleaning off flux after soldering? I’ve heard that it can be corrosive, so best practice is to clean/remove it after repairs. Is this something that parents tell their kids to scare them, or will I find my repaired electronics will be a corroded mess after 5 years? I sometimes use a lot of flux to make up for poor soldering skills. I do wipe it off a bit, but some things are still a little tacky and have that sweet resin smell.

My recommendation is to buy tools as you need them. That being said, stock up on the basics (quality Phillips and flat head screw drivers in all the sizes, pliers, tweezers, a stanley knife, you name it) and maybe a decent soldering station with all of the accoutrements.

In my experience, quality tools are almost always worth the extra cost. When it comes to basic hand tools, I would strongly recommend buying the best you can afford, because you’re going to use them all the time.

When it comes to more specialized tools like soldering equipment, it really depends on how often you are going to use them. If you’re just starting out, a 50 $ soldering kit is going to serve you pretty well. When I got a little more serious about electronics, I bought an 80 $ soldering station which I used for years, until after a couple of bad solder joints on some actual contract work caused by insufficient temperature control, I said to myself: “Fuck this, I’m buying a JBC”.

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In the spirit of the thread, here are some things that I have repaired or modified in the last several years.

We bought a toaster oven that had an excessively loud notification buzzer. We would toast bread and could taste the irony when the buzzer sounds like a fire alarm. I don’t remember the details too clearly, but I had to disassemble the whole thing to get to the piezo buzzer. I think I added another resistor in parallel to lower the power to it. It now has a muted tone that doesn’t scare the dogs.

The last thing I repaired was a Netgear R7800 wifi router that I bought off of ebay. The price was good, but the seller didn’t add any padding to the box, so when it arrived, two of the wifi antenna mounts had snapped off or broken. I was able to buy a donor router for $25 and transplanted the mounts to the working board. The wifi mounts had a large mass, so my little soldering iron wasn’t powerful enough by itself to simultaneously melt the solder on the 4 legs of the antenna mounts, so I ended up covering most of the board in foil and use a heat gun to remove the mounts. Fun times. There was also some drilling involved since my desoldering skills are worse than my soldering skills and the donor parts still had a little too much soldering in them to fit in the original holes.

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There are different types flux, some are corrosive, some are not. Generally, you should NEVER use corrosive flux when working on electronics, because if you don’t clean it off completely, it can actually corrode the traces and components. If the flux you are using is designed for electronics work, there is no harm in leaving it on (some types can even act like protective laquer).

If the packaging says “no clean”, then you can leave it on, no worries. Would you mind posting a picture, so I can tell you whether it’s safe for electronics or not (you mentioned a resin smell, so I assume it’s rosin based, which is generally safe)?

A general note on flux: Proper solder contains plenty of flux, so generally I don’t see the need to add more. When doing SMD work it can come in handy, but I mostly work with paste, so I primarily use it to remove stubborn shorts between pins.

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Thanks for the info!

Here is what I am using. I mostly use the bottle of rosin flux, although it’s getting cruddy and hard to open. I’m not sure if I have ever used the paste in the syringe.

I appreciate you sharing some of your endeavors.

Desoldering is actually a lot harder than soldering.

On the subject of circuit abuse: Stay tuned for my report of the repair I completed this afternoon.

That rosin based flux is definitely suitable for electronics, even without cleaning, although I would recommend giving the stuff in the syringe a try, as it’s probably a lot easier to work with.

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I am an absolute butcher with garbage tools when it comes to electronics repair, but it is definitely something I have been doing more of in recent years. I have a few cheap Bluetooth adapters for my headphones that came with terrible micro USB power, all of which have failed. I managed to salvage them by soldering in short pieces of USB cables from old computer mice and have USB extension cables run to my common sitting places where I hang my headphones to keep them charged.

I started building a soldering station with a cheap soldering iron after my ancient Radio Shack iron bit the dust, but I caught the plague and have been down for nearly 2 weeks. Hoping to put the finishing touches on it next week. I wouldn’t exactly recommend any of my tools or methods, but for simple stuff like fixing damage to car wiring harnesses it should do the job. It’s a little wooden tower with drawers made out of a steel stud I cut up with snips. I’m ready to make a boatload of drawers in similar fashion to hold all of my small parts. I’ll try to get some pics up when I’m feeling better.

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then you might be of help…
i have a mechanical keyboard. everything works apart from the backlight.
the caps lock led and numlock led both work fine.
but the per key lighting on the rest of the keyboard?.
that started to flicker, then it faded out. occasionally it would blink back into life only to fade again.

likely cause was dust and grime (i didnt realise how grubby it got till i opened it and then EWW!.)
anyways after cleaning out all the dustbunnies it came back on for a while. then went off completley.

the manufacturer refused the warranty as it was 2 months outside its 1 year warranty. so im looking to repair it… but did tell me it was likely a diode…
suggestions?.
i have a multimeter and both a 15 and 25w soldering iron’s.
but i have no idea what to look for, how to test it, or what to replace it with.

anyways… cheers if you can help.

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As promised, here’s what I’ve been working on today:

The power stage of a forklift motor controller (replacement cost ~2800 $). Bonus points if you can spot the issue! :wink:

Easy enough, right? Just solder on that binding post, Bob’s ya auntie, right? Well, yes and no. The question is, how do you solder these solid copper slugs without access to vapor phase soldering equipment? Making matters worse, the substrate of the PCB is alumin(i)um, which soaks away a lot of the heat you put into the solder joint.

This board is actually a returning patient. I previously attempted to solder this binding post back on, but the repair only lasted for a few months. What I did last time, is I put some solder paste onto the pads, heated up the binding post with a blowtorch until it was hot enough to melt solder and pressed it onto the PCB. While this approach kind of worked, there wasn’t enough heat to fully melt the paste (shown in the following two images).


On to the actual repair!

Step 1: Preheating
When in doubt, preheat! I placed the board onto my hot plate and set the temperature to 100 - 120 °C.

Step 2: Cleaning and Pre-tinning
With a bit of preheating on the PCB, I used my soldering station to clean and pre-tin the solder pad and binding post.


Step 3: Soldering
Now for the most important step: the actual soldering.

After the cleaning, I added a generous amount of flux to the solder pad. Using a blowtorch, I heated up the binding post until felt like it was hot enough and I then quickly pressed it down onto the PCB, which was still on the hot plate. The first time I did this, I didn’t use enough heat, so I had take the binding post off again (using the blowtorch, because no mortal soldering iron or hot air station is up to that task) and repeat the process. The second time round, I got a decent squeeze out of solder which tells me, I got a proper joint.

Round 2 - Fight!
For good measure, I checked if the other binding posts were still fully attached and sure enough, one of them was starting to detach, so I took it off (again using the blowtorch) and repeated the entire process, this time achieving a proper solder joint on the first try.

Results Time
Here is what the completed board looks like after I removed the flux residues:

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Let’s see what we can do for you.

First of all, are we talking RGB or single color backlight here?

If it’s single color, I suspect one of the LEDs might be broken which causes all of the other LEDs in series with it to not light up as well. This would also explain the flickering, because LEDs often do that when they die (the bond wires connecting the actual diode to the pins of the package break or detach and due to thermal expansion, they move around ever so slightly, sometimes making contact, sometimes not).
To diagnose this, take apart the keyboard, locate all of the backlight LEDs and measure them using the diode tester of your multimeter. In one direction, you should see about 1.6 V, in the other direction you should see an open circuit. If you’re measuring an open circuit in both directions, that LED is faulty and probably the cause of your problem.

If it’s RGB, things will get a lot more complicated (possible causes could be voltage regulators, faulty LEDs, a faulty microcontroller or God knows what). In that case I will need photos of the top and bottom of the PCB to help you further.

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A Multimeter that can do capacitance and diode checking. An oscilloscope when you can afford it / if you decide to get deep enough into repairing. A magnifier of sorts … thinking of the ones that have lights around the edge and big enough so you can look thru it with both eyes comfortably. A variable bench power supply.

Leeds … lots of leeds that can clamp / hook / prob into the circuits your looking at.

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Just had a thought as well to follow up with my previous post.

Get a sbc or 2 (raspberry pi / arduino) and run thru the projects there.

Be a good and cheap starting point for anyone of any age to learn the basics. IMHO!!!

Short follow-up on that motor controller: I got confirmation that the repair was successful, let’s hope it lasts this time.

On that note, here are a few of the other things I fixed over the past 2 or so years:

  • 2 ampflifiers
  • 3 CD players
  • A Blu-ray player
  • 3 casette decks
  • 2 turntables
  • My laptop (more maintenance than repair, altough I should fix my touchpad)
  • A 3D projector
  • A bunch of other small things around the house I’m not going to list

I buy cheap tools at Harbor Freight. A 15 watt soldering iron at first is what you need! A $7.50 rather than $250. The cheap screwdriver set, $2.95. Solder, GET LEAD rather than European’s solder, 70/29/1. There is side cutter, straight cutter, long nose, twisted nose, and regular pliers for $2.95 each. They last until they get hit by a 110 ac wire that is live. I have 15, 25, and 65 watt for over 35 years. READ READ READ.

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Will I be able to pry open my old Surface Pro 2? I found out this whole time that the tablet actually does turn on and just needed to be charged when I thought it was dead (I tried charging it before and it didn’t work). But that tablet hasn’t been used in over 4 years so the Solid State Drive in the tablet failed.

An lcr meter is not expensive and is great for measuring inductance, capacitance and resistance.
An o-scope can help you determine the low impedance side of a non polarized capacitor and you can view the wave form to measure and align rf transformers and the like.
Working with smd? You want a hot air soldering system