Author Topic: From no parts to decent stockpile, best approach?  (Read 685006 times)

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Offline ez24

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Re: From no parts to decent stockpile, best approach?
« Reply #100 on: July 03, 2016, 11:02:44 pm »
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Online wraper

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Re: From no parts to decent stockpile, best approach?
« Reply #101 on: July 03, 2016, 11:24:42 pm »
FWIW: Ebay buying experience and ratings list by GreenPhotons keeps getting better:
http://www.sciencetronics.com/greenphotons/?page_id=855
It's a linked list of sellers. Think of it as "the good, the bad, and the ugly" list  :-+
That good list is not so good. I know for sure that gc_supermarket as example sells tons of counterfeits (personal experience). Also if you take some time searching what they are selling, easy to find very obvious fakes, especially opamps.
 

Offline TomS_

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Re: From no parts to decent stockpile, best approach?
« Reply #102 on: July 15, 2016, 12:30:34 pm »
Translation: Have extras on hand to replace the ones you fry during experimentation.  ;D :-/O

This ^^

I've been hitting RS and Digi-Key over the past month buying bits to put together a prototyping environment. Also my local "retail electronics" chain store, but trying to avoid then add they are much more expensive.

Already fried an LED and transistor. ;D

Transistors I bought 20 of each NPN and PNP for pence a piece. Also a bunch of N and P channel logic level MOSFETs. The MOSFETs are all SMD but I found some little DIP adapter boards with Digi-Key, so that was a nice excuse to do some SMD soldering.

I like RS because they ship next day for free for almost everything (even if you only spend 20p!!!). If you can get enough parts together with Digi-Key they are generally a bit cheaper but only do free shipping over a certain cart value. Seems they originate everything from the US whereas RS has a warehouse in the UK.

Gotta love electronics, been having a lot of fun lately. :)
 

Offline JoeN

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Re: From no parts to decent stockpile, best approach?
« Reply #103 on: July 15, 2016, 05:39:25 pm »
Transistors I bought 20 of each NPN and PNP for pence a piece. Also a bunch of N and P channel logic level MOSFETs. The MOSFETs are all SMD but I found some little DIP adapter boards with Digi-Key, so that was a nice excuse to do some SMD soldering.

Every adapter board I have ever seen at a professional distributor like DigiKey has been hideously overpriced compared to what you can find from Chinese sellers on eBay.  Prototype boards don't have to be military/space quality to work.  The Chinese boards are all adequate quality from what I have seen and I have bought hundreds of them.  Also, if you ever want to get into doing PCBs, designing your own adapters is a good place to start.  Hopefully Britain has something like OSHPark.  OSHPark is $5 per square inch for three, postage paid, within the US.  For small parts it is very reasonable to make your own custom adapters.
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Offline TomS_

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Re: From no parts to decent stockpile, best approach?
« Reply #104 on: July 16, 2016, 01:27:39 pm »
Yeah. TBH I did kind of use them to bulk up my cart a bit to qualify for free shipping, which otherwise would have cost £12. The adapters together were less than £12, so win win. Otherwise yes they are quite pricey on an individual basis.

I ordered some more adapters from ebay just the other day, they should arrive early next week and I may likely do that again in the future if they turn out to be decent enough quality.

 

Offline Trigger

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Re: From no parts to decent stockpile, best approach?
« Reply #105 on: August 19, 2016, 02:23:47 pm »
And I always purchase *a lot* more of the a bit more specialized parts (ICs, power fets) than I actually need, because If I need them today I most likely will use them again in the future.
Translation: Have extras on hand to replace the ones you fry during experimentation.  ;D :-/O

P.S. I think someone needs to create a "magic smoke" smiley.

A wizard tapping a chip with his wand and smoke popping out.
 

Offline jonovid

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Re: From no parts to decent stockpile, best approach?
« Reply #106 on: August 27, 2016, 04:10:10 pm »
IMO cheap surplus Chinese electronic components from aliexpress works for me, Ok for most hobby electronics.  but the professionals use DigiKey. as  for electronic test equipment you'v come to the right place. Dave would know!  :)   as for my hobbyist lab all basic. tools , 3 millimeters one is analog,  one 10MHz oscilloscope  ,power supply's    battery's also make good bench power supply's   2 soldering irons , one sucker thing.  a solder pot.  cheap $20 Chinese videoscope /  microscope that saves video  for SMD work  , 2 desktop computers  25 or more electronic teardowns from off the street & numerous garage sales. - aliexpress also has bulk resisters & caps  as with all cheap surplus test everything before using. as many Chinese transistors are testing E-C-B not E-B-C  also many Chinese SMD components are in unmarked in rolls. Up-date- My system of organization is to use airtight Plastic food storage containers with lids in 2 Litre = .5 US-Gallons & 10 or 7 Litre.= 2.6 or 1.8 US-Gallons. No dust or lost sub miniature components screws or washers. also 10 Litre tubs can hold a whole electronics teardown in its entirety.  So my new components are organized into resealable zip plastic bags  taged with self-adhesive labels then put into the storage containers. I have tried mini storage Drawers, but I found them taking up too much space & letting the dust get in. still on the lookout for an ice cube tray with lid for un-striped SMD components.
« Last Edit: September 24, 2016, 05:26:54 pm by jonovid »
Hobbyist with a basic knowledge of electronics
 

Offline Cliff Matthews

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Re: From no parts to decent stockpile, best approach?
« Reply #107 on: August 29, 2016, 02:43:00 pm »
Optical drives are common trash, but contain more re-usable parts per square inch than most finds. This Instructables article is one of the most photo-rich I've seen. http://www.instructables.com/id/Disassembling-a-CDDVD-reader-and-reusing-its-parts/?ALLSTEPS
For those in countries blocking that site, I put the PDF here: http://docdro.id/PYtpmdE Cheers!  :-+
« Last Edit: September 06, 2016, 10:57:09 pm by Cliff Matthews »
 

Offline jonovid

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Re: From no parts to decent stockpile, best approach?
« Reply #108 on: September 23, 2016, 01:54:48 am »
Quote
Optical drives are common trash, but contain more re-usable parts per square inch than most finds
whole computers have more re-usable parts per square inch than most finds but are not as common in the trash nowadays
Hobbyist with a basic knowledge of electronics
 

Offline ez24

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Re: From no parts to decent stockpile, best approach?
« Reply #109 on: November 17, 2016, 05:49:06 pm »
Another way to see a "list" of stuff is to look at Dave's meter and scroll down to

"Customers Who Bought This Item Also Bought"

It seems like a reasonable list of things bought by people who bought his meter.  It is a list of decent stockpile of parts and tools.
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Offline TheDane

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Re: From no parts to decent stockpile, best approach?
« Reply #110 on: December 11, 2016, 04:21:06 pm »
AliExpress and Ebay is certainly an option if you want to keep the stockpile yourself  :-+.

Ham fests/auctions, or joining local electronic oriented clubs can be an interesting option as well, if you 'only' need a single (+ a few to blow up) item, for your prototype needs.
Beware that most of the stuff out there are mostly second hand, through hole and 'old tech' (No 0402 smd, fast flash micros, huge eeproms, etc).
Ham operators gone 'silent key' (dead&burried) can also be a good source, and huge caches of components can be had for no price for just carrying it all away, to relatives wanting outrageous prices  - depending on relations, etc. Be aware

Polyfuses are extremly usefull and recommended, when you start working on stuff and find that not everything wants to play as you want  :palm:

Getting a decent workshop takes a LONG time - and a lot of work. Happy hunting - sometimes gold awaits around the corner (and yeah - it's literally gold plated  ;D) you just have to find it.
« Last Edit: December 11, 2016, 04:28:24 pm by TheDane »
 

Offline cdev

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Re: From no parts to decent stockpile, best approach?
« Reply #111 on: December 31, 2016, 04:22:30 pm »
What are the best "Grab bags" or assortments out there?

 Ive bought several of these in the past, and although they are not good if you want a specific part they are good for when you need something, don't have it somewhere else, often you can find something that will work in your junkbox, the bigger it  is the better for that..

and also for serendipity, you might get a random part that leads you into learning something new that you would not have ever considered were you not presented with it.
"What the large print giveth, the small print taketh away."
 

Offline jazer

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Re: From no parts to decent stockpile, best approach?
« Reply #112 on: January 15, 2017, 07:46:27 am »
Old/broken electronics for donor parts are better than grab bags, which seem like floor sweepings more than anything else. You get random parts and they generally don't cost anything. Keeping stockpiles of broken electronic stuff has its downsides of course.

Depending on what you do, you'll find that you tend to go back to the same well over and over. For example, there are hundreds of resistor values available, but (especially if you mostly design your own stuff) you end up using the same half dozen or so for most things. Once you figure out which are you go to items, buying a bunch from ebay and the like is cheapest.
 

Offline jazer

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Re: From no parts to decent stockpile, best approach?
« Reply #113 on: January 15, 2017, 07:25:49 pm »
If you don't have any test instruments at all, a DMM is more than a little handy.  Also, having more than one is useful when monitoring something.

They can be had at very low cost, and free if you're in the US and have a Harbor Freight store nearby.  They give them away just for walking in their store.  See attached printable coupon or link:

http://www.hfqpdb.com/coupons/11_FREE_7_FUNCTION_DIGITAL_MULTIMETER_1482355038.9542.JPG

There's a teardown thread for it on this forum with lots of good info:
https://www.eevblog.com/forum/reviews/harbor-freight-cen-tech-90899-small-teardown/

It's not the best DMM in the world, of course, and Dave probably hates it, but it's useful for secondary measurements and much better than having no DMM at all.
 
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Offline eugenenine

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Re: From no parts to decent stockpile, best approach?
« Reply #114 on: January 16, 2017, 03:46:22 pm »
I gave most of my grab bag and pulls from old stuff to my kids.  I had so much odd value, odd size stuff that it wasn't worth the time and space.  When I'm working on something I order extras. 
 

Offline ez24

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Offline james_s

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Re: From no parts to decent stockpile, best approach?
« Reply #116 on: January 22, 2017, 10:14:13 pm »
I keep a stock of resistors, capacitors, IC sockets, LEDs, connectors and other bits that I use in lots of projects on hand but other stuff I usually buy as needed. The most challenging for me was actually connectors, there is an overwhelming variety of them available so what I've tended to do is find a series I like and then buy a selection of the most commonly used sizes along with the crimper or punchdown tool for them.

For random parts I also regularly pick through the E-waste bin at work and drag home various discarded equipment to tear down and harvest interesting bits from. That's a handy way to get stuff like crystal oscillators, inductors, relays, buttons/switches and heatsinks. You do need to be careful though, for reasons I don't understand, some companies frown upon salvaging junk. Drives me nuts because I despise waste and firmly believe that the most efficient form of recycling by far is re-use.
 

Offline jazer

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Re: From no parts to decent stockpile, best approach?
« Reply #117 on: January 23, 2017, 07:46:36 am »
Dave did a video showing the guts of stuff from the white van speaker scam that showed what looked like recycled parts inside some dubious quality audio components.

I've never seen something like that in person, but I suppose there might be a thriving Chinese component recycling market to do that on any large scale.

I agree that re-using components is the best form of recycling, rather than a land fill, or indiscriminately melting down piles of e-junk and using mercury for gold extraction, poisoning whole towns.

Semiconductors are probably OK since most have very long useful lives, but recycling electrolytic caps is bad news; they barely last in new stuff.
 

Offline Skyfox

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Re: From no parts to decent stockpile, best approach?
« Reply #118 on: January 23, 2017, 04:00:26 pm »
For my stockpile I've been collecting junk circuit boards since I was a kid and desoldering parts from them.  Only within the past year have I finally started trying to organize by labeling a couple of storage trays for 24-series resistors and capacitors, and getting other drawer units to start decluttering and unpacking my original overloaded storage things.  Also within the past year I've started looking up datasheets on parts so I have some information on what they are.  Oh, and wire...I've been collecting scrap wire since I was a kid whether it's multi-stranded stuff or solid core phone/data wire.

In recent years I started actually spending a little money on cheap parts from Tayda Electronics and Digikey, when I needed things I simply didn't have and didn't want to rig up something out of what I did have.  The EEVblog videos have helped greatly in understanding this stuff, even though I'm still at a very beginner level of knowledge.
 

Offline james_s

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Re: From no parts to decent stockpile, best approach?
« Reply #119 on: January 23, 2017, 04:57:12 pm »
I don't generally salvage electrolytic capacitors but there are exceptions based on where it's used in the circuit. It's been my experience that larger, higher value capacitors used in low frequency applications are usually in good shape. Output filter capacitors in switchmode regulators take a beating. Other types of caps are generally fine to salvage.
 

Offline jazer

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Re: From no parts to decent stockpile, best approach?
« Reply #120 on: January 28, 2017, 03:55:52 am »
This has been touched on before here but in ancient threads, and it's tangentially apropos for this discussion:

What's the prevailing wisdom for flux when soldering:
paste, liquid rosin, no-clean, flux-pen, harvested from your backyard pine tree, hope and prayer?

Any good sources? Name brand stuff vs. Chinese/ebay witches' brew?
 

Offline james_s

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Re: From no parts to decent stockpile, best approach?
« Reply #121 on: January 28, 2017, 08:43:10 am »
I normally just use the flux that's in the core of the solder. Sometimes I use a bit of additional liquid rosin flux for heavily oxidized connections.
 

Offline JoeN

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Re: From no parts to decent stockpile, best approach?
« Reply #122 on: January 28, 2017, 08:51:03 am »
I normally just use the flux that's in the core of the solder. Sometimes I use a bit of additional liquid rosin flux for heavily oxidized connections.

That works great for through-hole soldering.  For drag-soldering on SMT parts I tend to flux the heck out of the parts and board that then put the solder on with a chisel tip.  That works the best for me on SMT parts, especially when you are talking about QFP-100, QFP-144 type parts.
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Offline james_s

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Re: From no parts to decent stockpile, best approach?
« Reply #123 on: January 28, 2017, 09:10:01 am »
Yeah I was assuming through-hole. I do the same thing when I hand solder SMT parts, dab on a bit of liquid flux with a Q-tip and stroke a small blob of solder along the pins.
 

Offline jackzzj

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Re: From no parts to decent stockpile, best approach?
« Reply #124 on: February 12, 2017, 07:23:05 am »
I just bought some kits from ebay... have to wait for a long time :=\
 


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