John Rumm brought next idea :
Initially this was supposed to be due to a supply of dodgy caps made with a
stolen (but incomplete) electrolyte formula. However the problems seem to
have endured far longer than that alone would explain!

It does seem to be any application in high ripple conditions they seem to go
tits up first. So SMPSUs and voltage regulation applications seem
particularly prone. I always try and replace them with low ESR caps designed
for this application, and with a 10K hours life rather than the cheaper 2K
ones.

I agree entirely...

In the past couple of years, I've had three failures which I've
actually been bothered to repair - all turned out to be failed
electrolytic caps. One the was on the two year old washing machine
micro controller board. Second was sat receiver 13 month old. Third was
the PWM speed control for my cars heater fan, a tiny bi-polar
electrolytic in the actual power switching module.

At one time, when repairing not very old equipment, the electrolytic
would be the last things I would be checking for faults. Now it is the
first thing I look to.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

Harry Bloomfield wrote:
John Rumm brought next idea :
Initially this was supposed to be due to a supply of dodgy caps made
with a stolen (but incomplete) electrolyte formula. However the
problems seem to have endured far longer than that alone would explain!

It does seem to be any application in high ripple conditions they seem
to go tits up first. So SMPSUs and voltage regulation applications
seem particularly prone. I always try and replace them with low ESR
caps designed for this application, and with a 10K hours life rather
than the cheaper 2K ones.

I agree entirely...

In the past couple of years, I've had three failures which I've actually
been bothered to repair - all turned out to be failed electrolytic caps.
One the was on the two year old washing machine micro controller board.
Second was sat receiver 13 month old. Third was the PWM speed control
for my cars heater fan, a tiny bi-polar electrolytic in the actual power
switching module.

At one time, when repairing not very old equipment, the electrolytic
would be the last things I would be checking for faults. Now it is the
first thing I look to.

They always are the first thing on old valve equipment, after you have
checked all the valves.

It happens that The Natural Philosopher formulated :
Harry Bloomfield wrote:
John Rumm brought next idea :
Initially this was supposed to be due to a supply of dodgy caps made with
a stolen (but incomplete) electrolyte formula. However the problems seem
to have endured far longer than that alone would explain!

It does seem to be any application in high ripple conditions they seem to
go tits up first. So SMPSUs and voltage regulation applications seem
particularly prone. I always try and replace them with low ESR caps
designed for this application, and with a 10K hours life rather than the
cheaper 2K ones.

I agree entirely...

In the past couple of years, I've had three failures which I've actually
been bothered to repair - all turned out to be failed electrolytic caps.
One the was on the two year old washing machine micro controller board.
Second was sat receiver 13 month old. Third was the PWM speed control for
my cars heater fan, a tiny bi-polar electrolytic in the actual power
switching module.

At one time, when repairing not very old equipment, the electrolytic would
be the last things I would be checking for faults. Now it is the first
thing I look to.

They always are the first thing on old valve equipment, after you have
checked all the valves.

I agree, but this is fairly recent modern equipment.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

In article om,
Alan Deane wrote:
Capacitor failure seems to be far worse than it used to be, when I
worked in electronic repair (~15 years ago) I rarely had any issues with
caps, but now it's one of the first things I look for, especially in
SMPSUs, monitors & TVs.

A SMPS puts a far greater load on the caps than an analogue one.

--
*Indian Driver - Smoke signals only*

Dave Plowman London SW
To e-mail, change noise into sound.

In message , John
Rumm writes

I was toying with doing a wiki article on component level repair of
electronic stuff, since there seems to be so much otherwise decent kit
that dies these days for silly reasons like failing capacitors etc.


A few random thoughts - more to follow


Repair would entail correct diagnosis of the fault

Some boards are so cheaply built that unless you are good with a
soldering iron, you can detach a pad from the pcb

Decent equipment and practice are essential if you are not going to do
more harm than good. Attacking a PCB by someone who is inexperienced is
liable to end in tears


plated through holes, once the component lead is removed, if you then
reapply solder to the joint and can clean the hole out better with a
solder sucker

Surface mount devices are often glued to the pcb


for surface mounted devices, you can now buy a budget hot air gun

http://cpc.farnell.com/duratool/zd-9...-rework-statio
n/dp/SD01139?in_merch=Featured%20Products&MER=e-bb45-00001001

You can also buy a budget desoldering station if you want a new toy.
We've been using one for a couple of months now and it hasn't fallen
apart yet

http://cpc.farnell.com/duratool/d006...dp/SD01384?in_
merch=Featured%20Products&MER=e-bb45-00001001



--
geoff

On Jan 14, 12:21*am, geoff wrote:
In message , John
Rumm writes



I was toying with doing a wiki article on component level repair of
electronic stuff, since there seems to be so much otherwise decent kit
that dies these days for silly reasons like failing capacitors etc.

A few random thoughts - more to follow

Repair would entail correct diagnosis of the fault

exactly, and thats where ukdiy often falls down, and beginners cant
generally do it on their own.


plated through holes, once the component lead is removed, if you then
reapply solder to the joint and can clean the hole out better with a
solder sucker

you can, but I've never seen teh point. Just heat the hole and push
the component lead through.


NT

On 14/01/2012 03:32, NT wrote:
On Jan 14, 12:21 am, wrote:
In , John
writes



I was toying with doing a wiki article on component level repair of
electronic stuff, since there seems to be so much otherwise decent kit
that dies these days for silly reasons like failing capacitors etc.

A few random thoughts - more to follow

Repair would entail correct diagnosis of the fault

exactly, and thats where ukdiy often falls down, and beginners cant
generally do it on their own.

I don't think that anyone is suggesting detailed fault finding
techniques for digital electronics.

(which while not actually a massively difficult task with the right
equipment, its very easy to find yourself twiddling knobs on several
hundred grands worth of it in the process, which tends to put much of it
beyond most folks DIY budgets)

At the simplest level, a hell of allot of kit can be saved just by
spotting the caps that are bulging and spewing electrolyte all over the
place. If you want to get a bit deeper, then you can do plenty with a
multimeter, and even relatively specialist bits of kits like LCR
component analysers or ESR meters are not that expensive.

(I don't agree that ukdiy falls down on diagnosis either particularly -
we have some very good engineers here with plenty of experience in
relevant fields. That does not mean that all contributions or all advice
will be spot on, but its no reason to write it off either)

plated through holes, once the component lead is removed, if you then
reapply solder to the joint and can clean the hole out better with a
solder sucker

you can, but I've never seen teh point. Just heat the hole and push
the component lead through.

That works for many boards, but not all. In some cases a typical iron
delicate enough for the size of task can't supply the heat on a
multilayer board. That's where the hot air systems work well, either to
temper an area of board to give the iron a chance, or more typically on
their own just to reflow the obscured hole so it can be sucked clean.

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On Jan 14, 5:20*am, John Rumm wrote:
On 14/01/2012 03:32, NT wrote:



On Jan 14, 12:21 am, *wrote:
In , John
*writes

I was toying with doing a wiki article on component level repair of
electronic stuff, since there seems to be so much otherwise decent kit
that dies these days for silly reasons like failing capacitors etc.

A few random thoughts - more to follow

Repair would entail correct diagnosis of the fault

exactly, and thats where ukdiy often falls down, and beginners cant
generally do it on their own.

I don't think that anyone is suggesting detailed fault finding
techniques for digital electronics.

any fault finding for any electronics would be a move forward for the
beginner

(which while not actually a massively difficult task with the right
equipment, its very easy to find yourself twiddling knobs on several
hundred grands worth of it in the process, which tends to put much of it
beyond most folks DIY budgets)

At the simplest level, a hell of allot of kit can be saved just by
spotting the caps that are bulging and spewing electrolyte all over the
place. If you want to get a bit deeper, then you can do plenty with a
multimeter, and even relatively specialist bits of kits like LCR
component analysers or ESR meters are not that expensive.

(I don't agree that ukdiy falls down on diagnosis either particularly *-
we have some very good engineers here with plenty of experience in
relevant fields. That does not mean that all contributions or all advice
will be spot on, but its no reason to write it off either)

A problem I see here too often is a series of people simply taking
wild guesses. Its an approach that simply doesnt work often when
you're faced with an electronic system using 100s of parts.

For beginners to electronic repair I'd suggest
1. getting a multimeter
2. understanding that both power and signals flow through the circuit
stage by stage
3. Using the meter to spot where power or signal fails to be there,
thus narrowing the fault down to a specific small area of circuit.,
usually. I say usually as eg CRT TV PSUs can be extremely interlinked
with other parts of the tv.


NT

plated through holes, once the component lead is removed, if you then
reapply solder to the joint and can clean the hole out better with a
solder sucker

you can, but I've never seen teh point. Just heat the hole and push
the component lead through.

That works for many boards, but not all. In some cases a typical iron
delicate enough for the size of task can't supply the heat on a
multilayer board. That's where the hot air systems work well, either to
temper an area of board to give the iron a chance, or more typically on
their own just to reflow the obscured hole so it can be sucked clean.

On 14/01/2012 12:42, NT wrote:
On Jan 14, 5:20 am, John wrote:
On 14/01/2012 03:32, NT wrote:



On Jan 14, 12:21 am, wrote:
In , John
writes

I was toying with doing a wiki article on component level repair of
electronic stuff, since there seems to be so much otherwise decent kit
that dies these days for silly reasons like failing capacitors etc.

A few random thoughts - more to follow

Repair would entail correct diagnosis of the fault

exactly, and thats where ukdiy often falls down, and beginners cant
generally do it on their own.

I don't think that anyone is suggesting detailed fault finding
techniques for digital electronics.

any fault finding for any electronics would be a move forward for the
beginner

Perhaps there are two articles here - one on fault finding and one on
service technique?

(which while not actually a massively difficult task with the right
equipment, its very easy to find yourself twiddling knobs on several
hundred grands worth of it in the process, which tends to put much of it
beyond most folks DIY budgets)

At the simplest level, a hell of allot of kit can be saved just by
spotting the caps that are bulging and spewing electrolyte all over the
place. If you want to get a bit deeper, then you can do plenty with a
multimeter, and even relatively specialist bits of kits like LCR
component analysers or ESR meters are not that expensive.

(I don't agree that ukdiy falls down on diagnosis either particularly -
we have some very good engineers here with plenty of experience in
relevant fields. That does not mean that all contributions or all advice
will be spot on, but its no reason to write it off either)

A problem I see here too often is a series of people simply taking
wild guesses. Its an approach that simply doesnt work often when
you're faced with an electronic system using 100s of parts.

Perhaps not, but we are talking about a guide to method and technique
here, so that does not need to apply!

For beginners to electronic repair I'd suggest
1. getting a multimeter
2. understanding that both power and signals flow through the circuit
stage by stage
3. Using the meter to spot where power or signal fails to be there,
thus narrowing the fault down to a specific small area of circuit.,
usually. I say usually as eg CRT TV PSUs can be extremely interlinked
with other parts of the tv.

Indeed, and probably a good example of kit one ought not encourage the
inexperienced to go poking about in since they can bite...



--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On Sat, 14 Jan 2012 05:20:13 +0000, John Rumm wrote:
At the simplest level, a hell of allot of kit can be saved just by
spotting the caps that are bulging and spewing electrolyte all over the
place. If you want to get a bit deeper, then you can do plenty with a
multimeter, and even relatively specialist bits of kits like LCR
component analysers or ESR meters are not that expensive.

Agreed; after caps it's often bad solder joints, bad board interconnects
and IC sockets, shorted transistors and diodes in power stages - in other
words, 'logical' stuff that's easy to work your way through. I've seen
lots of "contamination" cases too - battery leaks, staples/paperclips
making their way inside cases, or even simple dirt and dust build-up
resulting in overheating.

ESR meters are funny - extremely useful, but at one point they seemed
difficult to find (I ended up building my own using bits from the junk
pile). I think they're more readily available these days, though.

cheers

Jules

On Fri, 13 Jan 2012 19:32:39 -0800, NT wrote:

plated through holes, once the component lead is removed, if you then
reapply solder to the joint and can clean the hole out better with a
solder sucker

you can, but I've never seen teh point. Just heat the hole and push the
component lead through.

A danger of taking the through-hole plating off if it's a tight fit?
Especially in a multi-layer board.



--
Use the BIG mirror service in the UK:
http://www.mirrorservice.org

*lightning protection* - a w_tom conductor

In article
,
NT wrote:
On Jan 14, 12:21 am, geoff wrote:
In message , John
Rumm writes



I was toying with doing a wiki article on component level repair of
electronic stuff, since there seems to be so much otherwise decent kit
that dies these days for silly reasons like failing capacitors etc.

A few random thoughts - more to follow

Repair would entail correct diagnosis of the fault

exactly, and thats where ukdiy often falls down, and beginners cant
generally do it on their own.


plated through holes, once the component lead is removed, if you then
reapply solder to the joint and can clean the hole out better with a
solder sucker

you can, but I've never seen teh point. Just heat the hole and push
the component lead through.

no use if the component you are trying to fit has multiple legs.


NT

--
From KT24

Using a RISC OS computer running v5.16

In message
, NT
writes
On Jan 14, 12:21*am, geoff wrote:
In message , John
Rumm writes



I was toying with doing a wiki article on component level repair of
electronic stuff, since there seems to be so much otherwise decent kit
that dies these days for silly reasons like failing capacitors etc.

A few random thoughts - more to follow

Repair would entail correct diagnosis of the fault

exactly, and thats where ukdiy often falls down, and beginners cant
generally do it on their own.


plated through holes, once the component lead is removed, if you then
reapply solder to the joint and can clean the hole out better with a
solder sucker

you can, but I've never seen teh point. Just heat the hole and push
the component lead through.

With a capacitor, yes - with an IC, no


--
geoff

In message , geoff
wrote

Surface mount devices are often glued to the pcb

Not in my experience. Solder is the only thing holding the component on
the board on 99.99% of commercial gear.

There may be board coatings on boards for the military market which make
rework almost impossible for those with out the right tools.

The only time I've seen glue used is when a physically very large
component has been fitted and the manufacturer has used a "blob" of glue
to bond to component case to the board to prevent differential physical
movement - to help prevent vibration failures.

--
Alan
news2009 {at} admac {dot} myzen {dot} co {dot} uk

In article ,
Alan wrote:
Surface mount devices are often glued to the pcb

Not in my experience. Solder is the only thing holding the component on
the board on 99.99% of commercial gear.

Not so. Most are glued in place as part of the manufacturing process then
flow soldered.

--
*I couldn't repair your brakes, so I made your horn louder *

Dave Plowman London SW
To e-mail, change noise into sound.

"Dave Plowman (News)" wrote in message
...
In article ,
Alan wrote:
Surface mount devices are often glued to the pcb

Not in my experience. Solder is the only thing holding the component on
the board on 99.99% of commercial gear.

Not so. Most are glued in place as part of the manufacturing process then
flow soldered.

None of the SM stuff I did was glued.
It was all solder paste and then into the vapour bath.

I don't think I have ever found glue on a SM component so it must be
something that varies from industry to industry.

On Jan 14, 7:17*pm, "dennis@home" wrote:
"Dave Plowman (News)" wrote in ...

In article ,
* Alan wrote:
Surface mount devices are often glued to the pcb

Not in my experience. Solder is the only thing holding the component on
the board on 99.99% of commercial gear.

Not so. Most are glued in place as part of the manufacturing process then
flow soldered.

None of the SM stuff I did was glued.
It was all solder paste and then into the vapour bath.

I don't think I have ever found glue on a SM component so it must be
something that varies from industry to industry.

Glue is used for double sided assembly and where boards need to be
wave soldered after smd assembly. It stops the smd components from
falling off.

MBQ

On 14/01/2012 09:33, Alan wrote:
In message , geoff
wrote

Surface mount devices are often glued to the pcb

Not in my experience. Solder is the only thing holding the component on
the board on 99.99% of commercial gear.

Its slightly less common than it was, since solder paste is now almost
universally used, and that tends to hold components in place until
soldering. On the earlier surface mount stuff where it was flow soldered
(usually on the "chip wave" rather than in the main bath) they had to be
glued fairly well else they would simply fall off the board once it was
inverted and fed through the wave.

There may be board coatings on boards for the military market which make
rework almost impossible for those with out the right tools.

Conformal coatings don't always make it much harder to remove and
replace stuff (although some are a right pig!), but it can be a pain
getting the coating back in place properly.

The only time I've seen glue used is when a physically very large
component has been fitted and the manufacturer has used a "blob" of glue
to bond to component case to the board to prevent differential physical
movement - to help prevent vibration failures.

Wogging as GEC used to call it...

(real vibration situations would usually call for stuff being tied down,
or clamped in place. Often with holes designed into the boards to make
that possible - or sometimes by fixing to the heat ladder when there is one)

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

In message , Alan
writes
In message , geoff
wrote

Surface mount devices are often glued to the pcb

Not in my experience. Solder is the only thing holding the component on
the board on 99.99% of commercial gear.


Then go and gain some more experience then ...

I presume it holds the component in place prior to the soldering process

--
geoff

On Jan 14, 7:49*pm, geoff wrote:
In message , Alan
writes

In message , geoff
wrote

Surface mount devices are often glued to the pcb

Not in my experience. Solder is the only thing holding the component on
the board on 99.99% of commercial gear.

Then go and gain some more experience then ...

I presume it holds the component in place prior to the soldering process

During can be more critical.

MBQ

geoff wrote:
You can also buy a budget desoldering station if you want a new toy.
We've been using one for a couple of months now and it hasn't fallen
apart yet

http://cpc.farnell.com/duratool/d006...dp/SD01384?in_
merch=Featured%20Products&MER=e-bb45-00001001

Is that essentially a solder sucker but with continuous vacuum, so no
plunger? A bit like those things that dentists use to clean up your mouth
after they've done the 'job'.

I've found solder wick to be good for removing solder (and on modern work
the quantities are usually small): the key is to add a little fresh solder
to the wick on the joint to make it flow properly. Fluxing the wick also
helps.

Theo

In article ,
Theo Markettos wrote:
geoff wrote:
You can also buy a budget desoldering station if you want a new toy.
We've been using one for a couple of months now and it hasn't fallen
apart yet

http://cpc.farnell.com/duratool/d006...dp/SD01384?in_
merch=Featured%20Products&MER=e-bb45-00001001

Is that essentially a solder sucker but with continuous vacuum, so no
plunger? A bit like those things that dentists use to clean up your
mouth after they've done the 'job'.

More a soldering iron with a hole up the middle of the bit with a vacuum
pump on the other end. With a few various filters between. A good one is
quick and very satisfactory to use. The hole can fit over the component
lead 'tail' and once the solder is melted you wiggle it slightly with the
pump running. Makes removing something like a multi-pin socket or whatever
pretty easy. But mainly for conventional sized stuff.

I've found solder wick to be good for removing solder (and on modern
work the quantities are usually small): the key is to add a little fresh
solder to the wick on the joint to make it flow properly. Fluxing the
wick also helps.

Yes - and much cheaper than a desolder station. But if you do a lot of
repair work the latter is invaluable. Perhaps the most famous make is
Pace, from the US. Their older units come up pretty often on Ebay, but are
much larger than a modern one - and often 110v only. Other good make is
Royal - but spares can be difficult.

--
*I'm not a complete idiot, some parts are missing *

Dave Plowman London SW
To e-mail, change noise into sound.

In message , "Dave Plowman (News)"
writes
In article ,
Theo Markettos wrote:
geoff wrote:
You can also buy a budget desoldering station if you want a new toy.
We've been using one for a couple of months now and it hasn't fallen
apart yet

http://cpc.farnell.com/duratool/d006...dp/SD01384?in_
merch=Featured%20Products&MER=e-bb45-00001001

Is that essentially a solder sucker but with continuous vacuum, so no
plunger? A bit like those things that dentists use to clean up your
mouth after they've done the 'job'.

More a soldering iron with a hole up the middle of the bit with a vacuum
pump on the other end. With a few various filters between. A good one is
quick and very satisfactory to use. The hole can fit over the component
lead 'tail' and once the solder is melted you wiggle it slightly with the
pump running. Makes removing something like a multi-pin socket or whatever
pretty easy. But mainly for conventional sized stuff.

I've found solder wick to be good for removing solder (and on modern
work the quantities are usually small): the key is to add a little fresh
solder to the wick on the joint to make it flow properly. Fluxing the
wick also helps.

Yes - and much cheaper than a desolder station. But if you do a lot of
repair work the latter is invaluable. Perhaps the most famous make is
Pace, from the US. Their older units come up pretty often on Ebay, but are
much larger than a modern one - and often 110v only. Other good make is
Royal - but spares can be difficult.


But the link I posted above is new, ready to go and has 12 months
warranty at a sensible price



--
geoff

In article ,
geoff wrote:
Yes - and much cheaper than a desolder station. But if you do a lot of
repair work the latter is invaluable. Perhaps the most famous make is
Pace, from the US. Their older units come up pretty often on Ebay, but
are much larger than a modern one - and often 110v only. Other good
make is Royal - but spares can be difficult.


But the link I posted above is new, ready to go and has 12 months
warranty at a sensible price

Think they must be quite recent. Last time I looked there were no
reasonably priced de-solder stations. I suppose it could be because the
hot air type has sort of replaced them.

--
*OK, who stopped payment on my reality check?

Dave Plowman London SW
To e-mail, change noise into sound.

On 14/01/2012 14:19, Theo Markettos wrote:
wrote:
You can also buy a budget desoldering station if you want a new toy.
We've been using one for a couple of months now and it hasn't fallen
apart yet

http://cpc.farnell.com/duratool/d006...dp/SD01384?in_
merch=Featured%20Products&MER=e-bb45-00001001

Is that essentially a solder sucker but with continuous vacuum, so no
plunger? A bit like those things that dentists use to clean up your mouth
after they've done the 'job'.

They are usually a combination of a high power iron, and a vacuum pump.
Often come with a foot switch or trigger on the iron to engage the suck.
Much easier to use than the manual pumps with a separate iron.



--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

In message , Theo Markettos
writes
geoff wrote:
You can also buy a budget desoldering station if you want a new toy.
We've been using one for a couple of months now and it hasn't fallen
apart yet

http://cpc.farnell.com/duratool/d006...dp/SD01384?in_
merch=Featured%20Products&MER=e-bb45-00001001

Is that essentially a solder sucker but with continuous vacuum, so no
plunger? A bit like those things that dentists use to clean up your mouth
after they've done the 'job'.

Yes, it has a heated tip to melt the solder, then you depress the
trigger and it sucks like an essex girl. An impulse action might have
been better but it's OK


I've found solder wick to be good for removing solder (and on modern work
the quantities are usually small): the key is to add a little fresh solder
to the wick on the joint to make it flow properly. Fluxing the wick also
helps.


Ah, but while its become an essential tool for us because of the amount
of use it gets, I felt it my duty to post the link for those who NEED a
new toy

--
geoff

On Sat, 14 Jan 2012 00:21:59 +0000, geoff wrote:

for surface mounted devices, you can now buy a budget hot air gun

Coupla folks over here have spoken well of the Aoyue range of SMD hot air
stations....

Thomas Prufer

John Rumm formulated on Friday :
I was toying with doing a wiki article on component level repair of
electronic stuff, since there seems to be so much otherwise decent kit that
dies these days for silly reasons like failing capacitors etc.

I was wondering what suggestions those of you who do this daily had to offer?

One of my favourite techniques for de-soldering, where the PCB will
allow it, is to heat up the solder joint and then quickly give the PCB
a sharp rap on the edge of the bench. Inertia then causes the hot
solder to keep going and which then leaves the component lead free to
be removed.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

On Jan 14, 9:52*am, Harry Bloomfield
wrote:
John Rumm formulated on Friday :

I was toying with doing a wiki article on component level repair of
electronic stuff, since there seems to be so much otherwise decent kit that
dies these days for silly reasons like failing capacitors etc.

I was wondering what suggestions those of you who do this daily had to offer?

One of my favourite techniques for de-soldering, where the PCB will
allow it, is to heat up the solder joint and then quickly give the PCB
a sharp rap on the edge of the bench. Inertia then causes the hot
solder to keep going and which then leaves the component lead free to
be removed.


Only when wearing jeans.

On Jan 13, 6:37*pm, John Rumm wrote:
I was toying with doing a wiki article on component level repair of
electronic stuff, since there seems to be so much otherwise decent kit
that dies these days for silly reasons like failing capacitors etc.

With modern lead free solder, and ever increasing layout densities, use
of multilayer boards etc, the job of component removal seems to be
getting ever harder. There was a time when a moderate iron with enough
bit mass to heat the joint quickly, was all you needed. To reflow the
joint and then either pull the device, or apply a solder sucker, all one
did was tin the bit, apply heat for a couple of secs, and job done.

Recently I have needed to recap a few motherboards (not usually an
economic exercise - but these were custom form factor jobbies where
replacements are not readily available), and they were a right PITA to
work on. Obviously multilayer, and since the caps are on the power
regulation sections, probably connected to fairly heavy power plane
traces in the board. Component removal was very difficult - often taking
excessive time for the joint to reflow. Tight pins in close holes with a
small annulus. However cleaning the holes for reuse proved impossible
with any of my normal irons. In the end I had to resort to using a hot
air paint stripper with small nozzle on the end to get enough heat into
the area to be able to suck the holes clear!

I was wondering what suggestions those of you who do this daily had to
offer?

--
Cheers,

John.

/================================================== ===============\
| * * * * *Internode Ltd - *http://www.internode.co.uk* * * * * *|
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| * * * *John Rumm - john(at)internode(dot)co(dot)uk * * * * * * *|
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Desoldering braid. Like co-ax braid but loaded with rosin (although I
think there is also a plain braid).
Flux, either a bottle of wet for use with a cocktail stick or artists
brush or a pen type.
Mechanical pencil. Clears the wet hole.
Tip cleaner, wetting and fluxing. The greater the cleaned surface
area of the tip, the more solder it will draw.
Bulb type sucker, which can be reserved for blowing. They don't have
the draw capacity of the sprung syringe but they are easier and
quicker to place because the hand may be stabilised by resting upon
the board.
Scrapers and point tools, to remove dry blobs.
I also like to use a gas iron which seems to have a higher heating
rate on a small bit, and I can switch hands without bothering with a
wire or getting my snozzle over the work.

On 14/01/2012 12:17, thirty-six wrote:
On Jan 13, 6:37 pm, John wrote:

I was wondering what suggestions those of you who do this daily had to
offer?

Desoldering braid. Like co-ax braid but loaded with rosin (although I
think there is also a plain braid).

I never used to be a fan of braid in the exclusively through hole days,
but its certainly quite handy on SM boards...

Flux, either a bottle of wet for use with a cocktail stick or artists
brush or a pen type.
Mechanical pencil. Clears the wet hole.
Tip cleaner, wetting and fluxing. The greater the cleaned surface
area of the tip, the more solder it will draw.
Bulb type sucker, which can be reserved for blowing. They don't have
the draw capacity of the sprung syringe but they are easier and
quicker to place because the hand may be stabilised by resting upon
the board.

Not as common as they once were... The point about lower height is a
good one though. I tend to use an Antex Mini de-soldering pump for that
very reason - its easier to use with the hand resting on the board.

Scrapers and point tools, to remove dry blobs.
I also like to use a gas iron which seems to have a higher heating
rate on a small bit, and I can switch hands without bothering with a
wire or getting my snozzle over the work.

Yup, they can be good... (although the last really difficult board I
had, even that would not re-flow the joint!)


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On Jan 14, 1:30*pm, John Rumm wrote:
On 14/01/2012 12:17, thirty-six wrote:

On Jan 13, 6:37 pm, John *wrote:
I was wondering what suggestions those of you who do this daily had to
offer?
Desoldering braid. *Like co-ax braid but loaded with rosin (although I
think there is also a plain braid).

I never used to be a fan of braid in the exclusively through hole days,
but its certainly quite handy on SM boards...

Me neither, but along with a heavy duty iron, they mop up quite quick
in power areas.
I'll be straight with you, it's 15 years since I held any repair
contract for part-time work.

Flux, either a bottle of wet for use with a cocktail stick or artists
brush or a pen type.
Mechanical pencil. *Clears the wet hole.
Tip cleaner, wetting and fluxing. *The greater the cleaned surface
area of the tip, the more solder it will draw.
Bulb type sucker, which can be reserved for blowing. *They don't have
the draw capacity of the sprung syringe but they are easier and
quicker to place because the hand may be stabilised by resting upon
the board.

Not as common as they once were...
Apparently not even worth mentioning when I was at college in 1983

The point about lower height is a
good one though. I tend to use an Antex Mini de-soldering pump for that
very reason - its easier to use with the hand resting on the board.

It's their speed of application which is their stronghold, for large
joints use a syringe which will generate more suction..

Scrapers and point tools, to remove dry blobs.
I also like to use a gas iron which seems to have a higher heating
rate on a small bit, and I can switch hands without bothering with a
wire or getting my snozzle over the work.

Yup, they can be good... (although the last really difficult board I
had, even that would not re-flow the joint!)

I've 3 and the common one I go to has an equivalent capacity of 75W,
the largest bit is possibly less than 1/4". It certainly seems at
least as good as a 75W electric and it is smaller and lighter. It's
a while since I've held a 75 or 80W iron because they have bits which
are too big in general but even so, I believe that the small gas iron
has a greater thermal gain than the stated electric equivalent, not
like 125W but certainly seems more than 75-80W. Guess 95-105W

I recall that in the olden days (if films were to be believed) if you were
stranded on a desert island with a radio set then you could convert it to a
transmitter!

Seriously, we are getting less able to repair or make items that can
interface with modern systems.

In message , DerbyBoy
wrote

I recall that in the olden days (if films were to be believed) if you
were stranded on a desert island with a radio set then you could
convert it to a transmitter!

But with modern electronics you can take one pixel from CCTV and
reconstruct a high definition image from it as seen all of the time on
CSI.
--
Alan
news2009 {at} admac {dot} myzen {dot} co {dot} uk

In article
,
thirty-six wrote:
Desoldering braid. Like co-ax braid but loaded with rosin (although I
think there is also a plain braid).
Flux, either a bottle of wet for use with a cocktail stick or artists
brush or a pen type.
Mechanical pencil. Clears the wet hole.
Tip cleaner, wetting and fluxing. The greater the cleaned surface
area of the tip, the more solder it will draw.
Bulb type sucker, which can be reserved for blowing. They don't have
the draw capacity of the sprung syringe but they are easier and
quicker to place because the hand may be stabilised by resting upon
the board.
Scrapers and point tools, to remove dry blobs.
I also like to use a gas iron which seems to have a higher heating
rate on a small bit, and I can switch hands without bothering with a
wire or getting my snozzle over the work.

They are expensive, but a proper vacuum desolder set is invaluable for
serious DIY. Older ones can be bought quite cheaply secondhand - but take
up much more room than modern ones.

--
*Reality is the illusion that occurs due to the lack of alcohol *

Dave Plowman London SW
To e-mail, change noise into sound.

On 14/01/2012 13:43, Dave Plowman (News) wrote:
In article
,
wrote:
Desoldering braid. Like co-ax braid but loaded with rosin (although I
think there is also a plain braid).
Flux, either a bottle of wet for use with a cocktail stick or artists
brush or a pen type.
Mechanical pencil. Clears the wet hole.
Tip cleaner, wetting and fluxing. The greater the cleaned surface
area of the tip, the more solder it will draw.
Bulb type sucker, which can be reserved for blowing. They don't have
the draw capacity of the sprung syringe but they are easier and
quicker to place because the hand may be stabilised by resting upon
the board.
Scrapers and point tools, to remove dry blobs.
I also like to use a gas iron which seems to have a higher heating
rate on a small bit, and I can switch hands without bothering with a
wire or getting my snozzle over the work.

They are expensive, but a proper vacuum desolder set is invaluable for
serious DIY. Older ones can be bought quite cheaply secondhand - but take
up much more room than modern ones.

Another godsend is a decent illuminated magnifier. I got one of the
anglepoise style ones with a circular fl tube recent - fantastic bit of
kit ;-)


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On Jan 14, 1:43*pm, "Dave Plowman (News)"
wrote:
In article
,
* *thirty-six wrote:

Desoldering braid. *Like co-ax braid but loaded with rosin (although I
think there is also a plain braid).
Flux, either a bottle of wet for use with a cocktail stick or artists
brush or a pen type.
Mechanical pencil. *Clears the wet hole.
Tip cleaner, wetting and fluxing. *The greater the cleaned surface
area of the tip, the more solder it will draw.
Bulb type sucker, which can be reserved for blowing. *They don't have
the draw capacity of the sprung syringe but they are easier and
quicker to place because the hand may be stabilised by resting upon
the board.
Scrapers and point tools, to remove dry blobs.
I also like to use a gas iron which seems to have a higher heating
rate on a small bit, and I can switch hands without bothering with a
wire or getting my snozzle over the work.

They are expensive, but a proper vacuum desolder set is invaluable for
serious DIY. Older ones can be bought quite cheaply secondhand - but take
up much more room than modern ones.

It's something I have considered, electronic repair did earn my bread
and butter many moons ago. At the time what was avaialable cost
hundreds and would have saved me 1/2 hour some days. The relative
expense then was too high. Today they are available for £40 or so,
but I can't justify the space in my home (whisky), despite my desire
for a quirky tool. I rarely come across repairable items which cannot
otherwise be dealt with. If I ever got stuck, other than "I could use
a desoldering unit" then I would reconsider buying one. At less than
£80 there is no question today, if it was for professional use where
it was used 10 times a day, I would buy. It is still not necessarily
the best choice for professional use, a soldering iron has a reater
bit choice for dealing with close circuits.