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From: JR North on 3 Jan 2010 22:53
Yup. the joints I reflowed appeared to not have the solder wick onto
the pins.
JR

On Mon, 4 Jan 2010 01:37:17 -0000, "Arfa Daily"
<arfa.daily(a)ntlworld.com> wrote:

>
>"David" <postings(a)REMOVE-TO-REPLYconfidential-counselling.com> wrote in
>message news:postings-D6C788.10292204012010(a)news.bigpond.com...
>> In article <stc0k593gpjtpc2skq0ipev8j2hd33ca99(a)4ax.com>,
>> JR North <junkjasonrnorth(a)bigfoot.com> wrote:
>>
>>> I love it when stuff works out. I'm not an electronics repair tech by
>>> any means, but can usually fix stuff anyway. Monitor would sometimes
>>> power up, but no screen. Other times, the screen brightness would
>>> slowly go up and down, then down to blank screen. A light whack on the
>>> case would usually fix it, temporarily. Eventually, the whack stopped
>>> working, and the monitor would not drive the screen at all. Almost
>>> pitched it, but decided to give it a shot first. Took the case apart,
>>> discharged the HV, removed the neck board and unsoldered/removed the
>>> shield on it. Reflowed the connections to the neck socket, and some
>>> other iffy-looking solder joints. Works great again.
>>> JR
>>> HOME PAGE:
>>> http://www.seanet.com/~jasonrnorth
>>> --------------------------------------------------
>>
>>
>> Dry joints seem to be one of the very common faults modern gear seems to
>> fall prey to - I wonder if they still have people inspecting and
>> correcting the soldering these days.
>>
>> Many years ago I spent a few days on a production line 'dryjointing'
>> circuit boards after they came through the solder bath. Mongrel of a
>> job, but when you are young you do what you are told.
>>
>> The girls that did this on a day to day basis complained of sore eyes
>> from the glare.
>>
>> Perhaps things have changed
>>
>> David
>
>Only for the worse I'm afraid, David. It's all lead-free solder now, and dry
>joints are a bigger problem than they they have ever been in the past - even
>back to the early days of printed circuit introduction, when the technology
>of automated soldering was young and immature ...
>
>The problem is made doubly bad by the utterly different characteristics of a
>lead-free bad joint. It is very typical for a joint to go intermittent
>completely randomly, but not be able to be provoked by physical disturbance,
>heating or freezing, and yet when you actually find the little mutha, it
>will often be such a bad joint that the solder has not stuck to the
>component leg at all, and you can actually pull it out of the board. Apart
>from that, you can no longer spot a bad joint at twenty paces, as you could
>with leaded solder. With lead-free, *all* joints look bad to the
>traditionally trained eye ...
>
>Arfa
>
HOME PAGE:
http://www.seanet.com/~jasonrnorth
--------------------------------------------------
From: N_Cook on 4 Jan 2010 03:34
Arfa Daily <arfa.daily(a)ntlworld.com> wrote in message
news:jDb0n.27133$p33.7746(a)newsfe20.ams2...
>
> "David" <postings(a)REMOVE-TO-REPLYconfidential-counselling.com> wrote in
> message news:postings-D6C788.10292204012010(a)news.bigpond.com...
> > In article <stc0k593gpjtpc2skq0ipev8j2hd33ca99(a)4ax.com>,
> > JR North <junkjasonrnorth(a)bigfoot.com> wrote:
> >
> >> I love it when stuff works out. I'm not an electronics repair tech by
> >> any means, but can usually fix stuff anyway. Monitor would sometimes
> >> power up, but no screen. Other times, the screen brightness would
> >> slowly go up and down, then down to blank screen. A light whack on the
> >> case would usually fix it, temporarily. Eventually, the whack stopped
> >> working, and the monitor would not drive the screen at all. Almost
> >> pitched it, but decided to give it a shot first. Took the case apart,
> >> discharged the HV, removed the neck board and unsoldered/removed the
> >> shield on it. Reflowed the connections to the neck socket, and some
> >> other iffy-looking solder joints. Works great again.
> >> JR
> >> HOME PAGE:
> >> http://www.seanet.com/~jasonrnorth
> >> --------------------------------------------------
> >
> >
> > Dry joints seem to be one of the very common faults modern gear seems to
> > fall prey to - I wonder if they still have people inspecting and
> > correcting the soldering these days.
> >
> > Many years ago I spent a few days on a production line 'dryjointing'
> > circuit boards after they came through the solder bath. Mongrel of a
> > job, but when you are young you do what you are told.
> >
> > The girls that did this on a day to day basis complained of sore eyes
> > from the glare.
> >
> > Perhaps things have changed
> >
> > David
>
> Only for the worse I'm afraid, David. It's all lead-free solder now, and
dry
> joints are a bigger problem than they they have ever been in the past -
even
> back to the early days of printed circuit introduction, when the
technology
> of automated soldering was young and immature ...
>
> The problem is made doubly bad by the utterly different characteristics of
a
> lead-free bad joint. It is very typical for a joint to go intermittent
> completely randomly, but not be able to be provoked by physical
disturbance,
> heating or freezing, and yet when you actually find the little mutha, it
> will often be such a bad joint that the solder has not stuck to the
> component leg at all, and you can actually pull it out of the board. Apart
> from that, you can no longer spot a bad joint at twenty paces, as you
could
> with leaded solder. With lead-free, *all* joints look bad to the
> traditionally trained eye ...
>
> Arfa
>
>

With the recent very cold spell recently in the UK do you expect a rush of
lead-free tin-pest intermittants in the coming weeks?
Even if the mediaeval organ builders knew not of allotropes , they knew tin
organ pipes would crumble to dust in the little ice age era.

Re the OP the signature is slow changes , usually indicating fault up around
the CRT neck

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://diverse.4mg.com/index.htm



From: N_Cook on 4 Jan 2010 04:24
Just researching for timeplot for degree of tinpest v temp (av) v temp (min)
http://www.youtube.com/watch?v=vVtCPw7RsW4
NPL artificially speeded up.
Still not found timeline curves for onset after severe temp minima


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://diverse.4mg.com/index.htm



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