Elecraft

Construction question

Classic

List

Threaded

9 messages Options

Clint Sprague

Construction question

I'm attempting my 1st contruction project in many
years...
CMOS4 keyer, and I have what is probably a pretty
stupid question that maybe others can answer for me
here. When you install a component on the printed
side of the circuit board, and then you tip the board
over to solder, what are accepted methods to keep the
compenent from falling off? I've read
that you should bend the leads to hold the component
onto the board
but I was wondering if this is the only acceptable
way?

Thanks for you info,
73 - Clint - WS1V

__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
http://mailman.qth.net/mailman/listinfo/elecraft

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

Mark J. Schreiner

Re: Construction question

I just took a certification class at work for IPC-610(D) whihc is for
solder inspection. So, I'm now authorized to answer your question! The
method of bending the leads over is called "cinching" the leads and is
acceptable as long as the component lead does not get close to other
circuit components, traces, leads, etc. that would violate any designed
minimum electrical spacing requirements. It doesn't take very much of a
bend to allow the parts to be held into place. You might not want to
bend them at 90 degree angles to make the leads flat with the board,
though because it would likely be more difficult if you need to perform
rework later.

Are there other methods? Well, IPC-610(D) did specify other methods as
well, actually. One was an example of a resistor that had a wire that
went over the top of it and was soldered through holes alongside the
resistor, but boards would have to be built specifically to do that and
I'm sure yours isn't. That example really only applied to axial lead
parts. The hold-down wire is really not used very often, although I did
see it used on some larger axial lead parts in old aerospace qualified
parts, and probably other applications where there may be a high
vibration environment. The other method that was mentioned was use of
some sort of adhesive or staking material. There were specifications on
how much you would apply, and then it gets messy as well to have to deal
with that stuff (what is the right stuff to use was not specified, the
class didn't address process issues, just inspection criteria of solder
joints). Although it wasn't addressed, I think that if you wanted you
could probably also just hold the component until at least one lead is
soldered (or for ICs and other long SIP or DIP packages leads on both
ends of the part).

Don't use too much solder, minimize the amount of time that you have the
soldering iron on the circuit pad & component lead, and inspect your
solder joints after soldering to make sure you don't have an accidental
short circuit to adjacent pads or other problems. The training we got
was pretty much common sense, but since common sense is lacking and
industry needs standards which they can use to specify acceptability,
IPC-610(D) seemed pretty good. I wish I had the course before
assembling my K2, but I think that in general my common sense was okay
anyway.

Have fun!

Mark, NK8Q

Clint Sprague wrote:

>I'm attempting my 1st contruction project in many
>years...
>CMOS4 keyer, and I have what is probably a pretty
>stupid question that maybe others can answer for me
>here. When you install a component on the printed
>side of the circuit board, and then you tip the board
>over to solder, what are accepted methods to keep the
>compenent from falling off? I've read
>that you should bend the leads to hold the component
>onto the board
>but I was wondering if this is the only acceptable
>way?
>
>Thanks for you info,
>73 - Clint - WS1V
>
>__________________________________________________
>Do You Yahoo!?
>Tired of spam? Yahoo! Mail has the best spam protection around
>http://mail.yahoo.com
>_______________________________________________
>Elecraft mailing list
>Post to: [hidden email]
>You must be a subscriber to post to the list.
>Subscriber Info (Addr. Change, sub, unsub etc.):
> http://mailman.qth.net/mailman/listinfo/elecraft
>
>Help: http://mailman.qth.net/subscribers.htm
>Elecraft web page: http://www.elecraft.com
>
>
>

_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
http://mailman.qth.net/mailman/listinfo/elecraft

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

Ron D'Eau Claire-2

RE: Construction question

In reply to this post by Clint Sprague

Clint, WS1V asked:

When you install a component on the printed side of the circuit board, and
then you tip the board over to solder, what are accepted methods to keep the
compenent from falling off? I've read that you should bend the leads to
hold the component onto the board but I was wondering if this is the only
acceptable way?

----------------------
Bending the leads is a common approach for components with easily-bent
leads, but it is not the only way.

One technique that I use (and you'll find described in some Elecraft
assembly manuals) is what I call "tack-soldering". In that case you position
the part and hold it with the finger(s) of one hand while you use your other
hand to touch the solder pad and one lead on the bottom of the board with a
soldering iron that has been wetted with a drop of solder.

This will transfer a small amount of solder to the lead and pad to hold the
part in place. Then you can check positioning and make adjustments quite
easily, if necessary, since only a tiny dab of solder is holding the part in
place. Once satisfied with the placement, you the solder the OTHER leads
first, going back to the original tack-soldered lead and soldering it
properly last.

A last note - you mentioned dealing with CMOS. Wear a grounded wrist strap
or touch an unpainted, grounded metal surface frequently while you work to
avoid damaging the CMOS devices with static electric charges accumulated on
your body. Depending upon the climate where you are, just wiggling a bit on
your chair can produce destructive charges. Do not attach yourself to a
ground directly, except when you touch a ground. If you use a wrist strap,
it should have at least a 1 megohm resistor in series with the strap and
ground to prevent the possibility of a serious electrical shock.

Ron AC7AC

_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
http://mailman.qth.net/mailman/listinfo/elecraft

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

Joseph Trombino, Jr

Re: Construction question

In reply to this post by Clint Sprague

----- Original Message -----
From: "Clint Sprague" <[hidden email]>
To: <[hidden email]>
Sent: Sunday, January 15, 2006 10:35 PM
Subject: [Elecraft] Construction question

Howdy Clint:

Bending resistor and capacitor leads over will prevent them from falling out
and provide a relatively stable means of soldering the leads and it's a
reliable technique.

Depending on the type of part (i.e., integrated circuit) I will also use
Scotch tape to hold components in place when you must turn the board over to
solder.

73, Joe W2KJ
I QRP, therefore, I am

_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
http://mailman.qth.net/mailman/listinfo/elecraft

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

Jessie Oberreuter

Re: Construction question

I generally just hold the part down with one hand, touch the iron to
the solder to get a little dab on the tip, and then tack down one lead.
After that, the part will generally stay in place and you can solder the
rest of the pins. Do be sure to re-solder that first lead as the tack is
often tenuous :).

On Mon, 16 Jan 2006, Joseph Trombino Jr wrote:

>
> ----- Original Message ----- From: "Clint Sprague" <[hidden email]>
> To: <[hidden email]>
> Sent: Sunday, January 15, 2006 10:35 PM
> Subject: [Elecraft] Construction question
>
>
>> I'm attempting my 1st contruction project in many
>> years...
>> CMOS4 keyer, and I have what is probably a pretty
>> stupid question that maybe others can answer for me
>> here. When you install a component on the printed
>> side of the circuit board, and then you tip the board
>> over to solder, what are accepted methods to keep the
>> compenent from falling off? I've read
>> that you should bend the leads to hold the component
>> onto the board
>> but I was wondering if this is the only acceptable
>> way?
>>
>> Thanks for you info,
>> 73 - Clint - WS1V
>
> Howdy Clint:
>
> Bending resistor and capacitor leads over will prevent them from falling out
> and provide a relatively stable means of soldering the leads and it's a
> reliable technique.
>
> Depending on the type of part (i.e., integrated circuit) I will also use
> Scotch tape to hold components in place when you must turn the board over to
> solder.
>
> 73, Joe W2KJ
> I QRP, therefore, I am
>
>
>
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
> http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/subscribers.htm
> Elecraft web page: http://www.elecraft.com
>

Ian Stirling, G4ICV, AB2GR

Re: Construction question

In reply to this post by Clint Sprague

On Monday 16 January 2006 03:35, Clint Sprague wrote:

> When you install a component on the printed
> side of the circuit board, and then you tip the board
> over to solder, what are accepted methods to keep the
> compenent from falling off?

I use a pencil eraser between the board and workbench
to hold the part in place. I don't like the look of
solder pads where the component leads have been bent.

Ian, G4ICV, AB2GR, K2 #4962
--
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
http://mailman.qth.net/mailman/listinfo/elecraft

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

Simon (HB9DRV)

Re: Construction question

Fine tool from Weller - the ESF 120:

http://www.f6blk.net/main_fr.php?page=9

and

http://www.labem.pl/obrazki%20weller/esf120.JPG

Simon Brown
---
http://blog.hb9drv.ch/

----- Original Message -----
From: "Ian Stirling" <[hidden email]>

> On Monday 16 January 2006 03:35, Clint Sprague wrote:
>
>> When you install a component on the printed
>> side of the circuit board, and then you tip the board
>> over to solder, what are accepted methods to keep the
>> compenent from falling off?
>
> I use a pencil eraser between the board and workbench
> to hold the part in place. I don't like the look of
> solder pads where the component leads have been bent.
>

David F. Reed

Re: Construction question

In reply to this post by Joseph Trombino, Jr

Joe,

I would suggest not getting scotch tape anywhere near any ESD sensitive
components.

It develops quite a charge due to the triboelectric effect when you
strip it off the reel, and as a result, if it does not outright kill the
device, it can make it a "walking wounded", working at first, but
failing early in its life; while many devices are designed with ESD
protection, many fail their qualifications testing for it, and it is
good to use safe ESD handling techniques in constructing electronic things.

--Dave, W5SV

Joseph Trombino Jr wrote:

> Howdy Clint:
>
> Bending resistor and capacitor leads over will prevent them from
> falling out and provide a relatively stable means of soldering the
> leads and it's a reliable technique.
>
> Depending on the type of part (i.e., integrated circuit) I will also
> use Scotch tape to hold components in place when you must turn the
> board over to solder.
>
> 73, Joe W2KJ
> I QRP, therefore, I am

Nick Waterman

Re: Construction question

> I would suggest not getting scotch tape anywhere near any ESD sensitive
> components.

I find those bits of black sponge that elecraft package their chips in to
be quite useful... once you've freed one or 2 of them up of course.

--
"Nosey" Nick Waterman, G7RZQ, K2 #5209.
use Std::Disclaimer; [hidden email]
Isn't it a bit unnerving that doctors call what they do "practice"?
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
http://mailman.qth.net/mailman/listinfo/elecraft

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com