[sdiy] The vagaries of identifying parts scavanged...

Sun Sep 11 06:05:32 CEST 2011

I would suggest a Hakko 808. It's a hell of a lot better than those radio shack things and not that exoensive. I got mine for $150.

Doug 
synthparts.com

--- On Sat, 9/10/11, aankrom <aankrom at bluemarble.net> wrote:

> From: aankrom <aankrom at bluemarble.net>
> Subject: Re: [sdiy] The vagaries of identifying parts scavanged...
> To: "aankrom" <aankrom at bluemarble.net>
> Cc: Synth-diy at dropmix.xs4all.nl
> Date: Saturday, September 10, 2011, 2:12 PM
> Some more tips: speaking of tips, you
> should tin the tip just like you would a normal iron, but
> tin the inside too. You only need to tin the tip about
> halfway up the outside. Sucking the excess solder off with a
> teflon tipped solder sucker is a good idea too. I don't find
> much use for those, but I have two anyway. Sometimes the
> bulb on the desoldering iron can lose it's firmness and
> therefore some force when sucking solder - a spare bulb
> saves the day.
> 
> Also, when desoldering potentially heat-sensitive chips,
> give it a rest between each pin. In fact feel the chip with
> your other hand to guage how hot it's getting. If it gets
> too hot, lick your finger and brush it over the chip. Or if
> you prefer not to work with spittle, keep a moist sponge
> handy. I suppose there's a risk of lead poisoning in the
> context of soldering & putting your fingers in your
> mouth. Maybe. One way to give the chip a rest when
> desoldering more than one at a time, desolder a single row
> of pins from a few chips, then do the other.
> 
> I use a clip-on heatsink for parts with long leads that for
> some reason I'm not just cutting or using a conventional
> soldering iron. Polystyrene caps come to mind.
> 
> Also if you have a Variac or a Powerstat or other variable
> transformer, you can make your 45 watt iron run cooler if
> need be. But be prepared for poor solder-suckage because the
> solder will cool faster.
> 
> AA
> 
> On Sat, 10 Sep 2011 15:53:49 -0400, aankrom <aankrom at bluemarble.net>
> wrote:
> > Radio Shack's 45 watt desoldering iron is a must-have.
> There are
> > others out there, but RS's is cheap and with proper
> maintenance will
> > serve you well for a good long time. Plan on using up
> tips. When you
> > buy the iron, buy at least two new tips. I can go
> through a tip in one
> > night. Save the old tips though! They come in handy
> for parts with
> > large diameter leads. Keep the hole in the tip clear.
> Use a really
> > small screwdriver or old drill bit wrapped tape -
> don't burn yourself.
> > Also tapping the iron on a hard edge can help. Do it
> while it's hot of
> > course. Don't smash the tip. Hit just behind the tip.
> Sometimes the
> > tube leading to the bulb needs cleared or the bulb
> needs emptied of
> > "rattlies". Carefully undo the clip with pliers and
> pull off the bulb.
> > Do it while it's hot - you'll see why when you're
> doing it. I made a
> > makeshift tool out off a coathanger. It's basically a
> length long
> > enough to go all the way to the tip head and then bent
> at a 90 degree
> > angle to effect a handle. Hold the iron with the bulb
> tube opening
> > down and carefully run the coathanger up the tube. Be
> careful of bits
> > of solder that melt when they hit the tip and flow
> back. It's mostly
> > charred gunk though. I usually replace the bulb's
> retaining clip with
> > a twist of wire - makes it easier to remove for
> cleaning time. After
> > you do this and replace the bulb, give it a good
> squueeze into a can
> > of some sort. I use a tuna can. After it gets about
> have full of
> > solder, I use my 200 watt iron and melt it all and I
> stuff a copper
> > scratch pad into it - instant soldering iron tip
> cleaner!
> > 
> > For easy jobs I use a normal soldering iron, sometimes
> with the help
> > of a small screwdriver to pry the lead up. This is
> usually when I'm
> > after Dale resistors on a double-sided board.
> Capacitors I can usually
> > get with just a soldering iron and a couple of gentle
> tugs. Like when
> > I'm after big mylar, polycarbonate, polystyrene, or
> polyphenylene
> > sulfide caps. (PPS caps are great for audio and other
> synth-DIY stuff
> > - not to mention tube circuits, since they're usually
> rated @ 1600
> > VDC...)
> > 
> > For getting choice surface mount parts, I use copper
> solder-wick,
> > also from Radio Shack. This requires some practice and
> finesse. I
> > usually use a screwdriver here to pry the part away,
> with judicious
> > application of the soldering iron for recalcitrant
> parts. Sometimes
> > you have to get them hot enough for the glue to give
> way. As you may
> > imagine, it works best for 8-pin parts, but I've got a
> couple of
> > surface mount NE/SA575's and even bigger parts. As to
> whether I
> > overheated them, I'm not sure yet.
> > 
> > It's a good idea to pre-sort your parts as you remove
> them. Unless
> > you like sifting through a huge pile.
> > 
> > Recent parts I've got: 4 LF398H's, 4 LF256H's, 8
> LM308AN's, several
> > CD4044, CD4028, MC14516 and other somewhat cool parts
> that I forget.
> > I'm still looking for a TA7136. I do have a TA7122.
> Some cable boxes
> > have uPC1406HA's in them. I found a BL3207 in a
> karaoke machine.
> > 
> > AA
> > 
> > On Sat, 10 Sep 2011 13:28:13 -0400, Noah Vawter
> > <nvawter at media.mit.edu>
> wrote:
> >> Funny story: when I was an undergrad I used a
> blowtorch to remove a
> >> large number of 74xx components from several
> 18"x36" circuit boards.
> >> It was definitely overkill.
> >> 
> >> AA, do you have some tips for people who want to
> take apart circuit
> >> boards easily to get components?
> >> 
> >> 
> >> On Sep 10, 2011, at 12:04 PM, aankrom wrote:
> >> 
> >>> Desoldering a part from a circuit board is
> only half the job. Well except when you remove parts that
> you already KNOW what they are.
> >>> 
> >>> I always like finding the odd FET. Lately I
> have been finding 2SK202's. Wonder how they'd perform with
> audio... Anyway, I was taking apart a tape deck with several
> "1212's" & "1202's", my immediate thought was some sort
> of pre-biased transistor (and I was right), but to really
> know what you have, it's good to hunt for a datasheet. But
> alls I have is a number. What prefix to start with? Well I
> usually just start with the numbers using
> datasheetcatalog.com. But you can get a heap of hits that
> way. You can try to guess 2SC or even something like "KTC".
> Today I discovered a new prefix to try: "SRC", made my Auk.
> >>> 
> >>> I used to throw out pre-biased transistors,
> until I began to find them in schematics for projects I
> wanted to build. Fortunately for me, "throw out" means I
> just chuck 'em in a big coffee can instead of a little
> plastic drawer.
> >>> 
> >>> Sometimes to identify parts I have to resort
> to looking them up in my old hardcopy NTE book or my VERY
> old hardcopy SK book. (Came in real handy for a bunch of RCA
> "Dynascan" parts beginning with "307-" 'What? It's just a
> 4030? a 4016? a CA3130?...')
> >>> 
> >>> AA
> >>>
> _______________________________________________
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> >>> Synth-diy at dropmix.xs4all.nl
> >>> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
> >> 
> >> Noah Vawter
> >> http://web.media.mit.edu/~nvawter 
> <-   Media Lab documentation
> >> http://exertion.pbworks.com   <- 
>   Ph.D. research
> >> http://Synthshopping.com   <- 
>   My commercial wing
> >> http://kaptheshampoo   <-   webcomic
> > 
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