My experience of electronic parts salvaging

[Vincent]

I'm going to start on the forum with this topic, which is quite interesting!

I'm lucky enough to have access to a local recycling centre with a real intention to give a 2nd life to as much stuff as possible. Grabbing stuff is allowed and even encouraged as a way to reduce the volume of material being sent to waste or recycling. I have grabbed enough fluorescent tubes and fixtures to light a mid-size workshop for probably over 20 years, and 5 big boxes full of old circuit boards from fairly recent electronics.

It's true that most consumer electronics use SMD components which are virtually useless. But since I started salvaging stuff I learned which devices contain the most useful stuff, I even found PICs! No kidding!

I always look for small-sized cooling devices, like wine bottle or water coolers. They often use a thermo-electric module, or even two in a water cooler I dismantled last year. The control boards I got were full of basic component (and were pretty much the same). Each one had a TL494 PWM controller, plus a LM358 amp-op many times.

I seemed to be pretty lucky with battery chargers. One of them had a ST LM339N and a 45uF 450V AC capacitor.

Smoke detectors have some components. The IC seems to be useless though... Carbon monoxide detectors on the other hand! If you find one like this, GRAB IT!



Those I took apart had a PIC in them! The older one are of the PIC16CE series which unfortunately are not reprogrammable, but the last one I got was more recent and inside there was a PIC16F, tada! Even though I probably couldn't read its content, I'm fairly sure I can write my own program.

Last year again, I got a sort of industrial control device which was a goldmine! There was a few UV EPROMs and a 8031, among other things. I would like to put that 8031 in use in a project one day, it's a vintage Intel from the late 1980s LOL.

Compact fluorescent lamps are fun to take apart and repair! I think I have over 30 CFLs successfully repaired.

I always like it when I see a newer washing machine, dryer or cooking range in the scrap metal area! From the last cooking range I dismantled with electronic boards in it, I got a bunch of OMRON 24V relays, a LM324N, a 24C02 and a bunch of other useful parts.

Microwaves also have a great deal of components. Most of them have a microcontroller, but since they're so mass-produced, the microcontroller seems to always be a mask-ROM type. So unless I can find a way to enable a form of external ROM access (kinda like a 8051), they're useless. However those microwaves always use relays to switch the magnetron TX and other parts on. I have a bunch of those relays now, many of them being OMRON! I even dismantled a 1980s microwave for fun and got a board with a VFD display and old, but very interesting discrete components. There's an IC on it, a TL507 ADC. It seems quite simple to understand and could be useful in a future project.

I remember I once found a commercial photocopier from which I got a fairly big Hosiden 240X64 graphic LCD display. Finding a datasheet for it was a pain in the @$$ but I was able to find one from a very similar part with the same pinout, which is an unusual 13-pin. The photocopier's power supply had a bunch of large components.

Upon my last visit this year at the recycling centre I got a Panasonic telephone system, and as I learned, commercial stuff often has more interesting stuff! I found a crapload of PCB-mounted relays, and even neon lamps! Makes sense to find such lamps since they run fine on both DC and AC, and both are used in a telephone network (at different moments though).

There's so much stuff I probably forget, but this may become my official "dumpster diving finds" topic, so chances are I'll add other finds in the future!

[SeanB]

Welcome to the Fox. Nice seeing you here as well.

[hiddensoul]

I am a big recycler as well, my Grandfather (Opa) lived through the depression after WW2 in Holland and he taught me the three R's

Recycle, Reuse, Re-purpose... I remeber as a child making stuff out of wood, he had jars of new nails but we had to remove old nials from the used timber and straighten them on the anvil for our projects, I still do this kind of thing today. I bought a kilogram of assorted computers screws from a PC recycler for a few dollars. It took me a month of sorting in front of the TV at night to sort them but was well worth it 

[peter.mitchell]

An assortment of random screws is VERY useful.
On a side note, is it more bothersome if one screw is left or if one is missing once something is reassembled?

[SeanB]

One short is always a bother, but one left over means either you start again or see if it still works.

With PC screws I took 5kg to the scrapyard last year, it barely made a dent. I was simply taking them out and seeing if they were nice, then tossing the not nice and those I had way too much of in the steel bin, made out of an old disposacan with a slot cut in the top like a big piggy bank. It was 30kg when it went in.

[hiddensoul]

An assortment of random screws is VERY useful.
On a side note, is it more bothersome if one screw is left or if one is missing once something is reassembled?

On both counts duct tape will fix it.. if you are missing one and something is loose tape it together, and if you have a screw left over and it doesn't fall apart tape the screw to the bottom of the case

[Vincent]

Well, it seems this whole salvaging thing always gets better and better! Look at what I got yesterday!



A working Tektronix 2215 oscilloscope, for free! Here the scope is showing the 60 Hz sine wave from the power grid after being stepped down by a cheapo chinese transformer. Maybe this would explain why the wave form isn't perfectly sinusoidal?



This time the probe is connected to the 1000Hz square wave test point. The only thing that this scope seemed to need is to be calibrated. However if I adjust it using the grid's 60Hz sine wave, it doesn't seem to measure the 1000Hz square wave's frequency accurately. One of them is obviously off. I would assume the square wave is fairly accurate and the grid's frequency could be slightly off, not sure though.

Otherwise this instrument seems to be in perfectly good condition. And that's not all! It came with both original probes, including the hooks and even what seems to be a small pot adjusting tool, one per probe, along with little red plastic things. It also came with the instructions (it's a photocopy of the 2215A version though). It definitely was taken care of! Seeing the dust and spider webs that were on the casing, and the smell, it's been in storage for quite some time!

Despite the fact I didn't touch an oscilloscope since technical school, I quickly remembered how the different settings work. But it's the first time I use an analog oscilloscope, no harder than the digital ones from school. Unlike some people I worked with at school, I don't need any Auto-Set button xD

[RobertoLG]

salvage are us hehehe (Opa Larsen)

[Tinkerer]

Hey! Thats the exact same detector I have! haha
So, the people were here to put a new AC unit in the house and an alarm goes off. The damned thing was so loud, we could only tell it was coming from the kitchen but not where in the kitchen haha. After much looking, we finally realized this detector was plugged to the wall and had started going off; seems we forgot it was there since the table had been moved over top of the area to make room.
As it turns out, the detector now always makes an alarm so something broke it(yep, took it outside and it still makes noise). I was thinking about sending it to Dave so that maybe he could make a video out of troubleshooting it or some such thing. I havent even opened it up myself.

[tautech]

Well, it seems this whole salvaging thing always gets better and better! Look at what I got yesterday!



A working Tektronix 2215 oscilloscope, for free! Here the scope is showing the 60 Hz sine wave from the power grid after being stepped down by a cheapo chinese transformer. Maybe this would explain why the wave form isn't perfectly sinusoidal?



This time the probe is connected to the 1000Hz square wave test point. The only thing that this scope seemed to need is to be calibrated. However if I adjust it using the grid's 60Hz sine wave, it doesn't seem to measure the 1000Hz square wave's frequency accurately. One of them is obviously off. I would assume the square wave is fairly accurate and the grid's frequency could be slightly off, not sure though.

The mains sinewave will be corrupted from various types of loads and likely will vary at different times of the day. SMPS loads are the worst for this.
Nothing to do with the transformer you have used.
The scope Cal signal must never be considered as a precision square wave source.
Scope should be adjusted only with a precision scope calibrator.
If you can return adjustments to previous settings, likely you will find they are close enough except for demanding work.

[Hydrawerk]

Oh shit, here in Europe we are not allowed to take stuff home from the recycling centre. 

[dannyf]

Two favorable stories:

1) I got a nearly full reel of Luminary CM3 chips (LM3S811?) when a production run ended. I gave it to a friend who teaches a local community college;

2) A co-worker of mine was given gazillions of Atmel's USB stick (AT90USB1286/87?). I got no less than 5 of them and he was happy giving them away.

[VK3DRB]

An assortment of random screws is VERY useful.

Too true. I have a large box of imperial and metric screws, nuts and washers from TVs, video recorders, amplifers etc, built up of 20 years. A fabulous varied collection that got me out of trouble many times over the years. Then one day, one of my kids took them outside to work on something and left them in the rainy weather for two weeks .

[VK3DRB]

I took 6 trailer loads of TV's and video recorders when I moved house in 1986, vowing never to hoard bits and pieces again. When I moved again 13 years later, I took 8 trailer loads of TV's, video recorders, PLC's and electronic test equipment to the tip.

Since then I am a reformed electronics hoarder. I am cold turkey. The new paradigm is if in doubt, throw it out. The trick is to calculate the value of the real estate all the stuff is taking up and then work out the cost of having to buy in parts when needed. Of course there are some parts you just cannot throw out, like high voltage capacitors.

[Fred27]

It's true that most consumer electronics use SMD components which are virtually useless.

What makes you say this? I'd say they're more likely to be worth keeping and easier to remove too.

[Kibi]

I grew up in Zimbabwe and I was interested in electronics from a very early age. There were no electronics shops around, so the only source of components for me was to salvage them from old equipment.
More recently, I have also found oscilloscopes in the dustbin, Tek 24xx series ones! I also have a smashed up Tek 475 which has donated some of its parts to worthy causes.

[Vincent]

The mains sinewave will be corrupted from various types of loads and likely will vary at different times of the day. SMPS loads are the worst for this.
Nothing to do with the transformer you have used.
The scope Cal signal must never be considered as a precision square wave source.
Scope should be adjusted only with a precision scope calibrator.
If you can return adjustments to previous settings, likely you will find they are close enough except for demanding work.

You're totally right, I forgot about those harmonics! That explains why the form wasn't perfect. But even that should not change its actual frequency, right? That's pretty much why I used it to adjust the scope using the knobs on the front (didn't touch any pot inside), assuming one cycle is 16.66ms, with 2ms/div, it would give me a rough idea where the trace should cross the center line on the Y axis. By lack of any precision calibrator, I guess it gives something accurate enough for basic beginner stuff.

How lucky are you! 
I'd go back.

What are the odds someone who knew what it was would come by and spot it?

In fact quite a few around are aware that this place gets interesting stuff like that! Earlier this year someone spotted a BK Precision scope just before I did! I literally missed it by a second! Plus the guy wanted the scope for the capacitors, uugh!  But hey, I'm quite happy I got that Tektronix 2215!

What makes you say this? I'd say they're more likely to be worth keeping and easier to remove too.

Well personally I hardly see myself working with say the tiny SMD components, aside from the ICs probably. Many parts don't seem to have any reference number on them, which isn't of much help when it's time to reuse said parts. But I guess with brand new components from a reel that's a different story, so maybe it's just me. 

I guess I'm just not a SMD kind of guy LOL. Old circuit boards are my favourite source of electronic parts, so obviously parts with no reference number are useless to me. Plus I'm preparing to build what I'll call a desoldering pot with a large, shallow tin bath optimized for mass-desoldering. Such a piece of equipment seems definitely easier to use with through-hole components LOL.

[tautech]

The mains sinewave will be corrupted from various types of loads and likely will vary at different times of the day. SMPS loads are the worst for this.
Nothing to do with the transformer you have used.
The scope Cal signal must never be considered as a precision square wave source.
Scope should be adjusted only with a precision scope calibrator.
If you can return adjustments to previous settings, likely you will find they are close enough except for demanding work.

You're totally right, I forgot about those harmonics! That explains why the form wasn't perfect. But even that should not change its actual frequency, right? That's pretty much why I used it to adjust the scope using the knobs on the front (didn't touch any pot inside), assuming one cycle is 16.66ms, with 2ms/div, it would give me a rough idea where the trace should cross the center line on the Y axis. By lack of any precision calibrator, I guess it gives something accurate enough for basic beginner stuff.

Glad you didn't touch the internal settings. 
Think of this:
You have used the Cal pot to adjust to a sinewave one millionth of the frequency the scope is capable of measuring. 

I'd say keep your eyes out for a Function generator or an AWG in your dumpster diving and if any good and checked to be accurate you might use that to check your well found Tek.

[Vincent]

LOL, just for the heck of it, I listed all the PIC16Fs I got from old circuit boards:

- One PIC16F876
- One PIC16F628A
- Two PIC16LF628As
- One PIC16F818
- Two PIC16F72s
- One PIC16F73
- One PIC16F916
- One PIC16F917

Glad you didn't touch the internal settings. 
Think of this:
You have used the Cal pot to adjust to a sinewave one millionth of the frequency the scope is capable of measuring. 

I'd say keep your eyes out for a Function generator or an AWG in your dumpster diving and if any good and checked to be accurate you might use that to check your well found Tek.

That's what I'm probably going to do, instead of simply buying one. I need a good adjustable soldering station before. I had the chance to use one for the 1st time last month... what a world of difference!

[alho]

It's true that most consumer electronics use SMD components which are virtually useless.

Worthwhile to Google for service manual. For example LG tv that I dumpster dived had very good component list(except PSU and display driver pcb) in service manual. I saved the PCBs to salvage SMD caps if I ever need them. It can be bit painful to go trough several pages long list to see if there is the value that I'm looking and then find right marking on silkscreen. But 2 PCB wont take much room and I dont have so much need to justify buying a quality component assortment

[TerraHertz]

Well, it seems this whole salvaging thing always gets better and better! Look at what I got yesterday!



A working Tektronix 2215 oscilloscope, for free!

Wow, lucky!
After a find like that, I'd camp out there.

It's amazing what some people will throw out.

[tggzzz]

I grew up in Zimbabwe and I was interested in electronics from a very early age. There were no electronics shops around, so the only source of components for me was to salvage them from old equipment.

Same was true for me, growing up in the '60s and '70s. I've still got some of the components, and my main supply of single-strand hookup wire is still stuff reclaimed from West Drayton air traffic control centre.

[atferrari]

I'm going to start on the forum with this topic, which is quite interesting!

I'm lucky enough to have access to a local recycling centre with a real intention to give a 2nd life to as much stuff as possible.

Maybe it is not in line with your original post, but when I started as a fresh ignorant ham, all components I could get were from salvage or donated by good people. And then I built my succesful first AM xmtr.

As a result , for years I disassembled everything that came to me as surplus, but then I realized that while I was creating a real stock of things, I was spending (wasting) my time. It is always the risk that you end wanting to "have everything" with you.

Of course, if you keep boards and mechanism still as they come, you need dedicated real state. Another serious problem.

Nowadays, the balance means to me, doing a cursory inspection, taking notes of relevant parts and discarding boards when there is more than one of the same type.

I ALWAYS keep INTACT  power supplies and their control buttons and keys. Nice useful building blocks. Printers are (where?) a very good source for them.

Keeping things "just in case", is a problem.

[tggzzz]

Oh shit, here in Europe we are not allowed to take stuff home from the recycling centre. 

I know of one recyling centre where people wishing to deposit rubbish/recycling have to run a gauntlet past people just outside the rubbish/recycling tip. They want to remove stuff (with permission) immediately before it reaches the recycling area.

I'm sure that happens elsewhere as well, unless the councils have found a way to stop such transactions being sone on the public highway!

[tggzzz]

But even that should not change its [50Hz] actual frequency, right?

The mains frequency will be 50Hz on average, where (to over-simplify) the averaging period is integral numbers of 24 hours. At any time in the 24 hours it may be a few Hz off, dependnig on the load.