What type of electronics are dangerous to take apart for learning purposes/scrapping?

Thread Starter

mbferguson

Joined Apr 23, 2017
94
A lot of the time, when you watch videos of smart electronics people on youtube, they will mention that they've been taking things apart since their childhood. I haven't been taking things apart because I'm sure that would've annoyed my parents to see their toys get dismantled like a serial killer version of squirrels or something.

I saw a video of someone making tesla coils by removing the transformers from a bunch of microwaves. He mentioned that it was dangerous to take apart microwaves, as a certain part of it could release toxic gas/dust if you damaged it while taking it apart.

What sort of things should I be on the look out for when I'm taking old electronics apart? Is it simply a case by case basis doing some research before hand? I'm gonna go to Goodwill and harvest the old electronics to "serial killer" them in my underground electronics laboratory.
 

spinnaker

Joined Oct 29, 2009
7,835
You don't learn by taking things apart. You learn by putting them together. Figure out a project you want to build and then build it. The 555 timer can be a lot of fun and it can be savely and cheaply powered with a wall wart.
 

wayneh

Joined Sep 9, 2010
16,400
A lot of the time, when you watch videos of smart electronics people on youtube, they will mention that they've been taking things apart since their childhood. I haven't been taking things apart because I'm sure that would've annoyed my parents to see their toys get dismantled like a serial killer version of squirrels or something.

I saw a video of someone making tesla coils by removing the transformers from a bunch of microwaves. He mentioned that it was dangerous to take apart microwaves, as a certain part of it could release toxic gas/dust if you damaged it while taking it apart.

What sort of things should I be on the look out for when I'm taking old electronics apart?
That's true about the magnetron in microwaves, the ceramic insulators can contain beryllium oxide which can be fatal when inhaled. But otherwise I've taken apart just about everything you can imagine and there are minimal risks.

Old solder (and much still in use by hobbyists like me) contains lead. So if you spend a lot of time desoldering to remove parts or whatever, it's good to use ventilation, always wash up afterwards, and don't eat while you're working!

TVs (and probably other appliances) used to have large capacitors that could store a sizable charge at a high voltage, and hold it a long time. If you ever encounter a big capacitor in a device that hasn't been unplugged for a week or more, you should take steps to discharge it.

I'd say most of my (minor) injuries were from sharp edges and stuff like that, nothing electrical.
 

Thread Starter

mbferguson

Joined Apr 23, 2017
94
How do you know that they're smart? I've seen too much crap on YouTube posted by stupid people.
I determine if someone is smart based upon how cool the thing they made is, or how hard I think it would be for myself to do it. Smartness is relative, so I guess the more I learn the less impressed I will be.
 

dl324

Joined Mar 30, 2015
11,845
I determine if someone is smart based upon how cool the thing they made is, or how hard I think it would be for myself to do it. Smartness is relative, so I guess the more I learn the less impressed I will be.
I've seen videos that idiots have posted on YouTube. They represented themselves as knowing more than me regarding some topic, but I could determine that they were idiots well before the end of the video.
 

tranzz4md

Joined Apr 10, 2015
310
You will not be able to gain the senses and level of experiential knowledge of someone that has been taking things apart since they were kids. Dr. Phil or Oprah could explain that, I will not.

The sort of things to look for when disassembling "electronics" would be things that could cause you harm!!! If small cuts on your hands are deemed harmful (by your standards) then be aware of sharp edges and points, AND WEAR HAND PROTECTION (gloves) if you wish to progress "unharmed". If burns are deemed undesirably harmful, DON'T USE HEAT OR FLAMES, or use protection.

You may chaffe at my direct and impolite responses, but you didn't learn these things innocently, sequentially, and deductively, so now you are actually asking to be told things which might be expected of you by others. Undoubtedly Spinnaker dislikes a bit of this too,, which should further solidify the credibility of this response.

After you've taken apart, and at least partially reassembled small, simple items, larger, more complex ones should follow. (If you haven't ruined a few things and been startled and sustained a few physically insignificant injuries however, you're not yet ready to move onward). Items massive enough, or holding enough potential energy to substantially harm you can easily be handled after a natural progression from smaller, simpler items. A bit of youthful naivete and self-confidence will do wonders here. Unfortunately, you will find that time has flown, and the acquired knowledge has come at the cost of the passage of months and years. Don't fret: you could've simply wasted all that time surfing the 'net.
 

Thread Starter

mbferguson

Joined Apr 23, 2017
94
You will not be able to gain the senses and level of experiential knowledge of someone that has been taking things apart since they were kids. Dr. Phil or Oprah could explain that, I will not.

The sort of things to look for when disassembling "electronics" would be things that could cause you harm!!! If small cuts on your hands are deemed harmful (by your standards) then be aware of sharp edges and points, AND WEAR HAND PROTECTION (gloves) if you wish to progress "unharmed". If burns are deemed undesirably harmful, DON'T USE HEAT OR FLAMES, or use protection.

You may chaffe at my direct and impolite responses, but you didn't learn these things innocently, sequentially, and deductively, so now you are actually asking to be told things which might be expected of you by others. Undoubtedly Spinnaker dislikes a bit of this too,, which should further solidify the credibility of this response.

After you've taken apart, and at least partially reassembled small, simple items, larger, more complex ones should follow. (If you haven't ruined a few things and been startled and sustained a few physically insignificant injuries however, you're not yet ready to move onward). Items massive enough, or holding enough potential energy to substantially harm you can easily be handled after a natural progression from smaller, simpler items. A bit of youthful naivete and self-confidence will do wonders here. Unfortunately, you will find that time has flown, and the acquired knowledge has come at the cost of the passage of months and years. Don't fret: you could've simply wasted all that time surfing the 'net.
You are right. I am permanently stunted from my years of playing xbox. I will never be able to make a voltage divider that works
 

DNA Robotics

Joined Jun 13, 2014
588
The reason curious kids take things apart is to see "what makes them tick". They usually start with mechanical things like clocks, relays and things with motors. Creative people can use donor parts like motors, pulleys, gears to make other things. Usually people take electronic things apart looking for components to use in their projects. The Tesla coil project or making a Jacobs Ladder from components in an old style TV are reasons to take electronic things apart.
 

BBee

Joined Dec 6, 2018
35
I think electromechanical things are the most informative. I was amazed for quite a while when I took the lid off a ceramic IC and looked at the chip under my microscope (just a kids model, but was good enough to see things).

Things to perhaps avoid are tubes (thermionic valves) as they are glass and have vacuum. A major point here is old style TV tubes. They require very expert handling as an implosion can, and has been, very dangerous. RF power transistors (I think beryllium oxide as above). Probably transistors in general as there would be little gain unless opened very carefully. Cadmium Sulphide in LDR's as poisonous (although the element can be seen so little to gain here). Some very old equipment used asbestos for insulation etc (probably one of the most overlooked problems).

Tracy
 

AlbertHall

Joined Jun 4, 2014
10,538
Microwave oven Magnetrons - toxic beryllium inside.

I do learn from taking things apart, not mindlessly plowing through, but methodically trying to understand what every part and feature does as I go.
There are (at least were, but some must still be about) oscilloscopes with beryllium oxide disks as part of the heatsinking for X and Y output transistors. They are pretty fragile and the dust is toxic.

As a lad I used to take things apart. At some point it occurred to me that a greater challenge would be to put them back together again into a working condition. That means that the dismantling procedure may need modification. This was certainly educational.
 

AlbertHall

Joined Jun 4, 2014
10,538
Old solder (and much still in use by hobbyists like me) contains lead. So if you spend a lot of time desoldering to remove parts or whatever, it's good to use ventilation, always wash up afterwards, and don't eat while you're working!
Lead was removed from solder mostly to avoid it ending up in landfill where it can pollute water courses.
The greatest chemical danger from solder isn't the lead but the flux. You can get sensitised to it resulting in an allergic reaction. If that happens then you can no longer be near soldering.
 

radiohead

Joined May 28, 2009
508
In electronics classes that I teach, after getting the students familiar with theory, schematics and components, I do an exercise of parts harvesting. If you are able to find an old VCR, stereo or TV, there are plenty of parts there to build economical "confidence" or "learning" circuits. There are IR emitters and receivers, sensors of all kinds, inductors, LEDs switches, and a host of other components. For example, if they are looking for a bipolar NPN transistor, they have to look up the data sheet on a component they found to make sure it is a transistor, not an FET, voltage regulator or a MOSFET.
As a no-brainer statement, never try to harvest parts with the appliance plugged in. Also discharge any high-capacity capacitors to avoid an unpleasant shock. There are numerous de-soldering techniques. I prefer de-soldering wick over a de-soldering iron or the solder-sucker.
So yes, you can learn a lot from organized dismantling of electronic boards.
 

Thread Starter

mbferguson

Joined Apr 23, 2017
94
In electronics classes that I teach, after getting the students familiar with theory, schematics and components, I do an exercise of parts harvesting. If you are able to find an old VCR, stereo or TV, there are plenty of parts there to build economical "confidence" or "learning" circuits. There are IR emitters and receivers, sensors of all kinds, inductors, LEDs switches, and a host of other components. For example, if they are looking for a bipolar NPN transistor, they have to look up the data sheet on a component they found to make sure it is a transistor, not an FET, voltage regulator or a MOSFET.
As a no-brainer statement, never try to harvest parts with the appliance plugged in. Also discharge any high-capacity capacitors to avoid an unpleasant shock. There are numerous de-soldering techniques. I prefer de-soldering wick over a de-soldering iron or the solder-sucker.
So yes, you can learn a lot from organized dismantling of electronic boards.
What is the best way to discharge a capacitor? I learned this the hard when I got spooked a bit by these big blue girls.

Fig. 1.1 - Two blue film capacitors, named because they are the biggest I've used so far. Big Bertha (top) and Ogtha (bottom).

I was able to discharge them by keeping my multimeter probes across the capacitors to measure them. It slowly chugged down from around ~290V and took like 2 1/2 minutes to do so.
 

OBW0549

Joined Mar 2, 2015
3,566
What is the best way to discharge a capacitor? I learned this the hard when I got spooked a bit by these big blue girls.
See that little white boy at the top, the one marked "5W 500Ω"? Take it and connect it across the capacitor for a few seconds. That'll discharge it quite nicely, with little or no drama.
 

wayneh

Joined Sep 9, 2010
16,400
The kind that are dangerous, and should not just be shorted, are big electrolytics. These can hold enough charge, at a high enough voltage, to present an actual danger and not just an annoyance of an unpleasant zap. By "big", I'd guesstimate that anything more than a cubic inch, with a high voltage rating, is worth looking out for.

Shorting certainly works, but with a big one you'll actually throw sparks and potentially damage the capacitor from the burst of current.
 
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