[sdiy] [OT] LM13700 spotted in commercial product of big Manufacturer

[David G Dixon]

The "secret" to my speed is that I buy resistors on tape strips.  If I need
60 resistors, then I cut off 5 strips of 12 resistors each.  Since the
resistors are spaced out on the tapes, the first thing I do is bend the
tapes at the halfway point such that 6 resistors slot inbetween the other 6
resistors.  This gives me 12 resistors tightly packed together.  Since all
resistors in my layouts are on 0.4" spacing, I take my long narrow pliers
and bend all of the resistor leads 90 degrees a short distance from the
resistor body on both sides.  Then I cut all of the resistor leads on one
side leaving about a centimeter of lead, and then on the other side.  This
gives me 12 perfectly bent and cut resistors in just a few seconds.  Bending
and cutting all 60 resistors takes about one minute.  Stuffing is actually
the most time-consuming part, but since I dress all of my PCB drill holes
(i.e., drill them twice, from both sides) and the resistors are so nicely
prepared, they basically fall into their holes.  Stuffing 60 resistors takes
about 3 minutes.  Once the PCB is stuffed, I take it to the garage for
soldering.  I have a square piece of plywood on my bench that I use for
soldering.  I pick up this piece of wood and hold the resistors against it,
then set it down so that the resistors don't fall out.  I push it down
firmly against the wood to ensure that all of the resistors are fully pushed
into their slots.  Then it's just a matter of soldering, which is very quick
-- soldering 60 resistors takes about 3 minutes.  Then I quickly snip off
all of the protruding leads into a garbage can that is always on the floor
to the left side of my chair -- 1 minute or less.  I quickly inspect all
joints against a strong light to catch any solder bridges -- 30 seconds,
maybe.  That's it.  The entire process takes about 10 minutes.  However,
it's not a race.  As I said, I do it for pleasure -- I'm watching TV or
listening to music or chatting with my wife.  If it took twice as long, I
wouldn't really mind.  It's a hobby, after all, not a job.

 

-----Original Message-----
From: Guy McCusker [mailto:guy.mccusker at gmail.com] 
Sent: Tuesday, May 17, 2022 2:31 AM
To: Roman Sowa
Cc: David G Dixon; synth-diy at synth-diy org
Subject: Re: [sdiy] [OT] LM13700 spotted in commercial product of big
Manufacturer

[CAUTION: Non-UBC Email]

Did David's ten minutes include soldering, clipping leads, inspection of
joints? He said "prepare and stuff" which I took not to include soldering --
particularly since he was watching TV at the time. If not then I don't think
Roman lost, because he had done the full assembly job.

(Ahhh but was Roman watching TV? If not then he has ten minutes of quality
viewing to catch up on.)

I will say this: you are both waaaay faster than me.

On Tue, May 17, 2022 at 10:14 AM Roman Sowa <modular at go2.pl> wrote:
>
> OK, challenge accepted!
>
> Partly because it's fun, partly because thought I can beat it and 
> partly because David is nice guy, I took the challenge and tried to 
> beat David's markup doing it in SMD, obviously without P&P.
> So for me it was 72 resistors of the same value, 0603 case. Preparing 
> board and parts, placing them and soldering took 15 and half minutes.
> So I've lost.
>
> But it was a valuable experience which I never did before - to measure 
> the time needed for this. Placing components took 5 minutes, which was 
> my biggest surprise, soldering one side 7.5 minutes and the other side 
> plus final inspection - 3 minutes.
> Like David, I solder SMD for pleasure, so when the time flies like 
> crazy I don't even notice it.
>
> Roman
>
>
> W dniu 2022-05-16 o 18:17, David G Dixon via Synth-diy pisze:
> > You're missing my essential point:  I build electronics by hand for 
> > pleasure.  I derive no pleasure from handling tiny parts that I can 
> > barely see and that have to be installed on the solder side of the 
> > PCB.  I have installed SMD parts on boards by hand, and it is almost
impossible for me.
> > On the other hand, I have systems for making through-hole PCBs and 
> > installing through-hole parts that make it a snap to do.  I'm 
> > actually a bit of a through-hole ninja.  For example, in one of my 
> > common builds, I require 60 10k resistors on two PCBs.  I can 
> > prepare and stuff those resistors in less than 10 minutes, while 
> > watching TV at the same time.  I defy anyone to do that with SMD
resistors without a pick-and-place machine.
> >
> >
> >
> > -----Original Message-----
> > From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] On Behalf 
> > Of Mike Bryant
> > Sent: Monday, May 16, 2022 3:20 AM
> > To: Gordonjcp; synth-diy at synth-diy.org
> > Subject: Re: [sdiy] [OT] LM13700 spotted in commercial product of 
> > big Manufacturer
> >
> > [CAUTION: Non-UBC Email]
> >
> >> Conversely, I pretty much gave up on constructing electronics until 
> >> I got
> > into doing SMD, because through-hole is such a fiddly pain in the 
> > arse to deal with.  SMD is so much easier.
> >> Gordon
> >
> >
> > Same here.   MUCH easier to get an assembly house to make it up for me
:-)
> >
> > And at the prices JLCPCB charge for assembly it's now often cheaper 
> > to do a re-spin than spend hours performing major surgery to a first
prototype.
> >
> >
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