[time-nuts] Vaperware Parts and pulse stretching circuits

[Didier Juges]

I personally have an MX-500P

I like that it turns itself off if you do not use it after a few minutes,
and it takes about 15 seconds to have the tip back into soldering
temperature, so there is no reason to leave it on any longer than you need
it then and now and the tip won't burn.

Tips and accessories are fairly expensive from Metcal but a lot of stuff is
available on eBay if you wait a little bit.
I have a nice collection of tips for various packages that I have
accumulated over the year, and I have the desoldering tool as well.

Highly recommended.

Didier KO4BB


On Sat, Apr 25, 2020 at 8:07 PM Bryan _ <bpl521 at outlook.com> wrote:

> They make quite a few models which one are you recommending?
>
> -=Bryan=-
>
> ________________________________
> From: time-nuts <time-nuts-bounces at lists.febo.com> on behalf of Bill
> Notfaded <notfaded1 at gmail.com>
> Sent: April 25, 2020 5:38 PM
> To: Discussion of precise time and frequency measurement <
> time-nuts at lists.febo.com>
> Subject: Re: [time-nuts] Vaperware Parts and pulse stretching circuits
>
> I totally agree with the Metcal soldering station!!!  I'll never go back to
> anything else.  I don't even use a scope.  I bought some magnifying glasses
> with 5 sets of different power lenses you wear like glasses.  It has built
> in led light and adjustable strap that hold it on your head off Amazon.
> Works great.  I can do all small surface mount stuff with them.  Plus I
> have my normal vision and hand eye coordination going that way.  Soldering
> under a scope or on a video monitor is a lesson all in itself!
>
> Bill
>
> On Sat, Apr 25, 2020, 6:15 AM Gerhard Hoffmann <
> ghf at hoffmann-hochfrequenz.de>
> wrote:
>
> >
> > Am 25.04.20 um 13:41 schrieb John Ackermann:
> > > I do have a microscope (cheap Chinese unit, maybe $400 with articulated
> > arm and the works) and it does make things much easier.  But as long as
> you
> > can see the work, you can do the job.
> > >
> > > It's not that hard to do small pitch parts.  I usually do the best I
> can
> > soldering individual pins, knowing their will be bridges, then clean up
> > with solder wick and *lots* of no-clean flux.  You can never have too
> much
> > flux.  I've found a 1.6 mm chisel tip is a good all around size for SMD
> > work, though I have a 0.8 mm chisel available for when things get tight.
> > >
> > > The hardest part is getting the first couple of pins tacked down so the
> > part is square on the pads.  After that it's fast.
> > >
> > > John
> >
> > I have about the same here, plus a cheap Chinese Ayoue852 hot air
> > station. Exchanging the Weller for a Metcal was the biggest improvement
> > after the LED ringlight for the microscope.
> >
> > In my quest to scrutinize the 1/f region, I have built some chopper
> > amplifiers and the newest one will have GaN transistors that are nekkid
> > chips with jut 4 tin bumps below. No case, just the passivated chip, 1 *
> > 1 mm, EPC2038. Low channel resistance, even lower capacitance -> low
> > charge injection. Resistors are 0603.
> >
> > Fearing I could not handle them, I made a minimum version of the switch
> > itself as a test structure in an unoccupied corner of a different
> > project. But soldering did take just 3 minutes, it was surprisingly
> > easy. Just keep the air flow low enough, or you will have trouble to
> > find the chips again. The thick-liquid flux helps to fix the chips in
> > place.
> >
> > Legible part numbers on the board are hopeless at this scale. The board
> > was made by PCBway, there were some discussions about having solder mask
> > ON part of the pads, and some discussions with our German customs that
> > you cannot buy 10 boards for $10 or so.
> >
> > The chips are the gray squares between the 2 vias on the left and the 4
> > huge coupling capacitors.
> >
> > Cheers, Gerhard
> >
> >
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