Toshiba TV29C90 problem; Image fades to black...

[Archimedes' Lever]

On Mon, 24 Nov 2008 10:28:13 +0000, f825_677 <f825_677@com.ntlworld>
wrote:

Arfa Daily wrote:

As Graham says, but be aware that unless you are a *very* experienced
solderer, and posess the right desoldering equipment, you will struggle to
do the job. These are some of the very worst bitches to get out of a board,
that you will *ever* come across. And then some.


You should try a Sony 1602 or 1601 IC from one of their broadcast mixer
boards - it can take an hour if you're lucky and all day if you're not
and we have professionaly desoldering vacumme equipment - the holes are
barely larger than the pin its self every engineer working on these
things in every broadcast engineering department complaints about these
devices.. Give me a 100 pin BGA device any day..

Desoldering a through hole part on a multi-layer PCB can be difficult,
especially if the part in question or the PCB is sinking all of your
solder tip heat away.

I have two good solutions. First one is to pre-heat the entire PCB
assembly to about 160F. That will keep the heat from sinking away so
much.

You can also heat the local area with a heat gun. This works even
better with the pre-heated PCB. The soldering operations generally take
place without a hitch in these cases.

 

[Archimedes' Lever]

On Mon, 24 Nov 2008 11:18:33 +0000, Eeyore
<rabbitsfriendsandrelations@hotmail.com> wrote:

f825_677 wrote:

Arfa Daily wrote:

As Graham says, but be aware that unless you are a *very* experienced
solderer, and posess the right desoldering equipment, you will struggle to
do the job. These are some of the very worst bitches to get out of a board,
that you will *ever* come across. And then some.

You should try a Sony 1602 or 1601 IC from one of their broadcast mixer
boards - it can take an hour if you're lucky and all day if you're not
and we have professionaly desoldering vacumme equipment - the holes are
barely larger than the pin its self every engineer working on these
things in every broadcast engineering department complaints about these
devices.. Give me a 100 pin BGA device any day..

If you know the IC's buggered (or even of low commercial value), cut every pin
and remove them individually. Then clean the holes up. It always wins on time and
cost.

Graham

Absolutely. If the part being removed is not part of the salvage
operation, cut all pins, remove the part, and then desolder each pin
individually. You could also fill the open holes with solder, and
dog-ear the new chip's pins outward and make it a surface mount install.

 

[Archimedes' Lever]

On Mon, 24 Nov 2008 23:01:01 +0000, Eeyore
<rabbitsfriendsandrelations@hotmail.com> wrote:

Tom Del Rosso wrote:

"Eeyore" <rabbitsfriendsandrelations@hotmail.com> wrote in message
f825_677 wrote:

You should try a Sony 1602 or 1601 IC from one of their broadcast
mixer boards - it can take an hour if you're lucky and all day if
you're not and we have professionaly desoldering vacumme equipment
- the holes are barely larger than the pin its self every engineer
working on these things in every broadcast engineering department
complaints about these devices.. Give me a 100 pin BGA device any
day..

If you know the IC's buggered (or even of low commercial value), cut
every pin and remove them individually. Then clean the holes up. It
always wins on time and cost.

Isn't that a PGA? Hard to cut the pins.

Is it ? I was referring to pinned ICs. Use a flame thrower on a PGA
! ;-)

If it is a ceramic package, that is not far from the best way to remove
it.

I would: Heat the PCB up a couple hundred degrees F, then heat the
ceramic chip package body up with a high temp heat gun, while inverted.
A heat gun on the bottom of the board should cause a near instant reflow,
and release of the chip.

The chip and pins get real hot. The PCB assembly only gets hot enough
to perform the reflow/release operation.

 

[f825_677]

Eeyore wrote:

f825_677 wrote:

Arfa Daily wrote:

As Graham says, but be aware that unless you are a *very* experienced
solderer, and posess the right desoldering equipment, you will struggle to
do the job. These are some of the very worst bitches to get out of a board,
that you will *ever* come across. And then some.
You should try a Sony 1602 or 1601 IC from one of their broadcast mixer
boards - it can take an hour if you're lucky and all day if you're not
and we have professionaly desoldering vacumme equipment - the holes are
barely larger than the pin its self every engineer working on these
things in every broadcast engineering department complaints about these
devices.. Give me a 100 pin BGA device any day..

If you know the IC's buggered (or even of low commercial value), cut every pin
and remove them individually. Then clean the holes up. It always wins on time and
cost.

Graham


sadly that is not an option, the device is a constructed ceramic case of other devices

within with the pins on the underside of the case - rather like a BGA device but pins and
not blobs if you understand what I mean. The board has an exchange value with Sony of
Ł1050 and they will only accept a board for exchange if not physically damaged, so being
careful and taking time is the only option..

 

[f825_677]

ian field wrote:

"Eeyore" <rabbitsfriendsandrelations@hotmail.com> wrote in message
news:492A8D89.C6735563@hotmail.com...

f825_677 wrote:

Arfa Daily wrote:

As Graham says, but be aware that unless you are a *very* experienced
solderer, and posess the right desoldering equipment, you will struggle
to
do the job. These are some of the very worst bitches to get out of a
board,
that you will *ever* come across. And then some.
You should try a Sony 1602 or 1601 IC from one of their broadcast mixer
boards - it can take an hour if you're lucky and all day if you're not
and we have professionaly desoldering vacumme equipment - the holes are
barely larger than the pin its self every engineer working on these
things in every broadcast engineering department complaints about these
devices.. Give me a 100 pin BGA device any day..
If you know the IC's buggered (or even of low commercial value), cut every
pin
and remove them individually. Then clean the holes up. It always wins on
time and
cost.

Graham


If you make sure none of the pins are bent on the solder side sometimes its
possible to just lift the pins out one by one on the tip of the iron, if the
pin is sheared off close to the IC body it leaves a slight hook on top,
simply hook the tip of the iron under it and add fresh solder - this runs
down the pin providing heat transfer to the solder joint and the surface
tension holds the pin on the tip as you lift it out of the hole.

Yes I've employed that method on convential type devices - but the device I describe is
somewhat different - have a look at the datasheet you'll see what I mean.
Its a 41 pin device about an inch square - all pins on the underside

 

[f825_677]

Tom Del Rosso wrote:

"Eeyore" <rabbitsfriendsandrelations@hotmail.com> wrote in message
news:492A8D89.C6735563@hotmail.com
f825_677 wrote:
You should try a Sony 1602 or 1601 IC from one of their broadcast
mixer boards - it can take an hour if you're lucky and all day if
you're not and we have professionaly desoldering vacumme equipment
- the holes are barely larger than the pin its self every engineer
working on these things in every broadcast engineering department
complaints about these devices.. Give me a 100 pin BGA device any
day..
If you know the IC's buggered (or even of low commercial value), cut
every pin and remove them individually. Then clean the holes up. It
always wins on time and cost.

Isn't that a PGA? Hard to cut the pins.


Yes it is - and you're right.

 

[f825_677]

ian field wrote:

"Arfa Daily" <arfa.daily@ntlworld.com> wrote in message
news:NuuWk.8598$mr6.2892@newsfe12.ams2...
"Eeyore" <rabbitsfriendsandrelations@hotmail.com> wrote in message
news:492A2208.4ACCA0F8@hotmail.com...

Meee wrote:

I was wondering why vertical mounting electrolytics have like an
indented cross on them.
To release the pressure and gunk under fault conditions (or bad
manufacture).


The reason I ask is because there's 4 largeish
one around my CPU on the motherboard and they have all split open,
along the indentations.
Oh dear.

A: How old is it ? (from date of manufacture)

B: Can you read what brands they are ?

C: Has your PC sharted behaving strangely yet ?

D: What brand mobo is it ?

E: Replace ASAP with well-known brand, low ESR (switching) types.
As Graham says, but be aware that unless you are a *very* experienced
solderer, and posess the right desoldering equipment, you will struggle to
do the job. These are some of the very worst bitches to get out of a
board, that you will *ever* come across. And then some.

Arfa


They certainly can be difficult, an absolute must is an iron with sufficient
power to heat the joint through quickly (DO NOT use one of those soldering
guns that passes low voltage/high current through a solid copper element -
they induce destructive currents in the PCB traces!).

Usually the 2 wires can be eased out by tilting the capacitor as one of the
solder joints is melted and then the other until its out.

Clearing the holes also isn't easy, solder wick won't do it you need a
solder sucker and a lot of practice getting enough of the iron tip on the
tinned pad and still leave enough gap to suck the solder through - you will
probably have to go at it from both sides too!

Once or twice out of sheer desperation I've heated the through hole and
swatted the board on the edge of the bench to knock the solder out, but this
has a real risk of breaking any crystals on the board!


Good soldering is a skill - and to be practiced as often as possible if you don't want

your work to look like a flock of seagulls have flown over

 

[f825_677]

Archimedes' Lever wrote:

On Mon, 24 Nov 2008 23:01:01 +0000, Eeyore
rabbitsfriendsandrelations@hotmail.com> wrote:


Tom Del Rosso wrote:

"Eeyore" <rabbitsfriendsandrelations@hotmail.com> wrote in message
f825_677 wrote:
You should try a Sony 1602 or 1601 IC from one of their broadcast
mixer boards - it can take an hour if you're lucky and all day if
you're not and we have professionaly desoldering vacumme equipment
- the holes are barely larger than the pin its self every engineer
working on these things in every broadcast engineering department
complaints about these devices.. Give me a 100 pin BGA device any
day..
If you know the IC's buggered (or even of low commercial value), cut
every pin and remove them individually. Then clean the holes up. It
always wins on time and cost.
Isn't that a PGA? Hard to cut the pins.
Is it ? I was referring to pinned ICs. Use a flame thrower on a PGA
! ;-)

If it is a ceramic package, that is not far from the best way to remove
it.

I would: Heat the PCB up a couple hundred degrees F, then heat the
ceramic chip package body up with a high temp heat gun, while inverted.
A heat gun on the bottom of the board should cause a near instant reflow,
and release of the chip.

And all the other SMT devices will fall off the board as well - would right off the board
its a Ł1050 exchange PCB from Sony, but to buy new is Ł11,600, the whole mixer at purchase
was just over Ł300,000 its not a cheap piece of equipment, but then a lot of broadcast kit
is expensive and needs special knowledge to be worked on.

I saw one of our junior engineers employ your method - I prefer my guys to use time and
patience over speed and probable damage.

 

[ian field]

"f825_677" <f825_677@com.ntlworld> wrote in message
news:tAQWk.7654$Gv7.7397@newsfe01.ams2...

Archimedes' Lever wrote:
On Mon, 24 Nov 2008 23:01:01 +0000, Eeyore
rabbitsfriendsandrelations@hotmail.com> wrote:


Tom Del Rosso wrote:

"Eeyore" <rabbitsfriendsandrelations@hotmail.com> wrote in message
f825_677 wrote:
You should try a Sony 1602 or 1601 IC from one of their broadcast
mixer boards - it can take an hour if you're lucky and all day if
you're not and we have professionaly desoldering vacumme equipment
- the holes are barely larger than the pin its self every engineer
working on these things in every broadcast engineering department
complaints about these devices.. Give me a 100 pin BGA device any
day..
If you know the IC's buggered (or even of low commercial value), cut
every pin and remove them individually. Then clean the holes up. It
always wins on time and cost.
Isn't that a PGA? Hard to cut the pins.
Is it ? I was referring to pinned ICs. Use a flame thrower on a PGA
! ;-)

If it is a ceramic package, that is not far from the best way to remove
it.

I would: Heat the PCB up a couple hundred degrees F, then heat the
ceramic chip package body up with a high temp heat gun, while inverted.
A heat gun on the bottom of the board should cause a near instant reflow,
and release of the chip.


And all the other SMT devices will fall off the board as well - would
right off the board its a Ł1050 exchange PCB from Sony, but to buy new is
Ł11,600, the whole mixer at purchase was just over Ł300,000 its not a
cheap piece of equipment, but then a lot of broadcast kit is expensive and
needs special knowledge to be worked on.

I saw one of our junior engineers employ your method - I prefer my guys to
use time and patience over speed and probable damage.

Most electronics tool suppliers stock pencil blowlamps which would be
precise enough to desolder a decent size ceramic chip, some are sold in sets
with a variety of nozzle attachments. The spread is way more precise than a
heat gun.

For smaller chips it might be worth looking out for one of those "windproof"
lighters that uses the same design of jet as the pencil blowlamp - only
smaller.

 

[Tom Del Rosso]

"ian field" <gangprobing.alien@ntlworld.com> wrote in message
news:4gVWk.44570$oK4.23531@newsfe18.ams2

Most electronics tool suppliers stock pencil blowlamps which would be
precise enough to desolder a decent size ceramic chip, some are sold
in sets with a variety of nozzle attachments. The spread is way more
precise than a heat gun.

I think he's saying that you can't apply heat to the component side at all,
even if it's directed only at the target device, because the package in
question is a hybrid with SMT parts exposed on its own surface.

For smaller chips it might be worth looking out for one of those
"windproof" lighters that uses the same design of jet as the pencil
blowlamp - only smaller.

--

Reply in group, but if emailing add one more
zero, and remove the last word.

 

[ian field]

"Tom Del Rosso" <td_03@att.net.invalid> wrote in message
news:492c3441$0$14299$607ed4bc@cv.net...

"ian field" <gangprobing.alien@ntlworld.com> wrote in message
news:4gVWk.44570$oK4.23531@newsfe18.ams2

Most electronics tool suppliers stock pencil blowlamps which would be
precise enough to desolder a decent size ceramic chip, some are sold
in sets with a variety of nozzle attachments. The spread is way more
precise than a heat gun.

I think he's saying that you can't apply heat to the component side at
all,
even if it's directed only at the target device, because the package in
question is a hybrid with SMT parts exposed on its own surface.

If its going in the bin once removed, that hardly matters.

 

[Jim Yanik]

"ian field" <gangprobing.alien@ntlworld.com> wrote in
news:1HWWk.32297$9I7.7910@newsfe19.ams2:

"Tom Del Rosso" <td_03@att.net.invalid> wrote in message
news:492c3441$0$14299$607ed4bc@cv.net...

"ian field" <gangprobing.alien@ntlworld.com> wrote in message
news:4gVWk.44570$oK4.23531@newsfe18.ams2

Most electronics tool suppliers stock pencil blowlamps which would be
precise enough to desolder a decent size ceramic chip, some are sold
in sets with a variety of nozzle attachments. The spread is way more
precise than a heat gun.

I think he's saying that you can't apply heat to the component side at
all,
even if it's directed only at the target device, because the package in
question is a hybrid with SMT parts exposed on its own surface.


If its going in the bin once removed, that hardly matters.

if you are removing it,it's likely because it's bad,and I would not try to
salvage such a part for reuse on another board.
I'm not even sure that BGA parts CAN be reused.(reliably)

I note manufacturers rework BGA boards by that "preheat and hot air"
method.

--
Jim Yanik
jyanik
at
kua.net

 

[Steve Sousa]

"f825_677" <f825_677@com.ntlworld> wrote in message
news:tAQWk.7654$Gv7.7397@newsfe01.ams2...

And all the other SMT devices will fall off the board as well - would
right off the board its a Ł1050 exchange PCB from Sony, but to buy new is
Ł11,600, the whole mixer at purchase was just over Ł300,000 its not a
cheap piece of equipment, but then a lot of broadcast kit is expensive and
needs special knowledge to be worked on.

I saw one of our junior engineers employ your method - I prefer my guys to
use time and patience over speed and probable damage.

have you seen http://www.oxygendct.com/acatalog/OxyChip_ICs.html ?

Best Regards

Steve sousa

 

[Eeyore]

Jim Yanik wrote:

if you are removing it,it's likely because it's bad,and I would not try to
salvage such a part for reuse on another board.
I'm not even sure that BGA parts CAN be reused.(reliably)

I read they can be re-balled apparently ! Unlike eunuchs.

Graham

 

[Archimedes' Lever]

On Tue, 25 Nov 2008 10:38:45 +0000, f825_677 <f825_677@com.ntlworld>
wrote:

Archimedes' Lever wrote:
On Mon, 24 Nov 2008 23:01:01 +0000, Eeyore
rabbitsfriendsandrelations@hotmail.com> wrote:


Tom Del Rosso wrote:

"Eeyore" <rabbitsfriendsandrelations@hotmail.com> wrote in message
f825_677 wrote:
You should try a Sony 1602 or 1601 IC from one of their broadcast
mixer boards - it can take an hour if you're lucky and all day if
you're not and we have professionaly desoldering vacumme equipment
- the holes are barely larger than the pin its self every engineer
working on these things in every broadcast engineering department
complaints about these devices.. Give me a 100 pin BGA device any
day..
If you know the IC's buggered (or even of low commercial value), cut
every pin and remove them individually. Then clean the holes up. It
always wins on time and cost.
Isn't that a PGA? Hard to cut the pins.
Is it ? I was referring to pinned ICs. Use a flame thrower on a PGA
! ;-)

If it is a ceramic package, that is not far from the best way to remove
it.

I would: Heat the PCB up a couple hundred degrees F, then heat the
ceramic chip package body up with a high temp heat gun, while inverted.
A heat gun on the bottom of the board should cause a near instant reflow,
and release of the chip.


And all the other SMT devices will fall off the board as well

WRONG!

A 150 degree F assembly is NOT at solder reflow temperature.

- would right off the board

WRONG! You PRE-heat the PCB. You only heat to reflow temp, the IC
chip you are removing. D'OH!

its a Ł1050 exchange PCB from Sony, but to buy new is Ł11,600, the whole mixer at purchase
was just over Ł300,000 its not a cheap piece of equipment,

Yeah, and you are not very brainy to think that someone would tell you
to reflow the entire board. Learn to read. Then learn how to properly
comprehend what you read.

but then a lot of broadcast kit
is expensive and needs special knowledge to be worked on.

No. It needs a proper technician. Nothing special about that. Just
educated.

I worked at General Instrument. I know about racks that cost $2M each,
and the broadcast industry had to buy our gear.

I saw one of our junior engineers employ your method

No, you didn't. Obviously, since you have a bent fucking perception of
what "my method" is.

- I prefer my guys to use time and
patience over speed and probable damage.

You're a goddamned presumptuous idiot. The method I described IS how
one removes a part from a board. You need to learn about heat sources
and sinking. In the case I described, the heat is applied to the IC
chip. So, what gets damaged?

 

[Eeyore]

ian field wrote:

If its going in the bin once removed, that hardly matters.

I heard a story (likely true) of an MD who went round the factory after
'time', pulling components back out of the bin and replacing them on the
bench.

Graham

 

[Tom Del Rosso]

"Archimedes' Lever" <OneBigLever@InfiniteSeries.Org> wrote in message
news:r93pi4tk8v11rrp9lfkhl9199jeqqb6fvd@4ax.com

On Tue, 25 Nov 2008 10:38:45 +0000, f825_677 <f825_677@com.ntlworld
wrote:

its a Ł1050 exchange PCB from Sony, but to buy new is Ł11,600, the
whole mixer at purchase was just over Ł300,000 its not a cheap piece
of equipment,

Yeah, and you are not very brainy to think that someone would tell
you to reflow the entire board. Learn to read. Then learn how to
properly comprehend what you read.

You refer to "the entire board". He refers to a PCB, but not the one you
think. The part in question is a PCB in itself. It's a hybrid module with
its own SMT parts, so you can't heat the whole part.

Google the part number and see what it looks like.


--

Reply in group, but if emailing add one more
zero, and remove the last word.

 

[ian field]

"Eeyore" <rabbitsfriendsandrelations@hotmail.com> wrote in message
news:492CF1DB.FEDB4DA6@hotmail.com...

ian field wrote:

If its going in the bin once removed, that hardly matters.

I heard a story (likely true) of an MD who went round the factory after
'time', pulling components back out of the bin and replacing them on the
bench.

Graham

The stupidest suits tend to float to the top!

 

[Eeyore]

ian field wrote:

"Eeyore" <rabbitsfriendsandrelations@hotmail.com> wrote
ian field wrote:

If its going in the bin once removed, that hardly matters.

I heard a story (likely true) of an MD who went round the factory after
'time', pulling components back out of the bin and replacing them on the
bench.

The stupidest suits tend to float to the top!

He also bought cheap thousands of TL072s that been salt-water contamined on a
sea voyage IIRC.

You can imagine what that did to the returns rate !

Graham

 

[Archimedes' Lever]

On Wed, 26 Nov 2008 02:37:48 -0500, "Tom Del Rosso"
<td_03@att.net.invalid> wrote:

"Archimedes' Lever" <OneBigLever@InfiniteSeries.Org> wrote in message
news:r93pi4tk8v11rrp9lfkhl9199jeqqb6fvd@4ax.com
On Tue, 25 Nov 2008 10:38:45 +0000, f825_677 <f825_677@com.ntlworld
wrote:

its a Ł1050 exchange PCB from Sony, but to buy new is Ł11,600, the
whole mixer at purchase was just over Ł300,000 its not a cheap piece
of equipment,

Yeah, and you are not very brainy to think that someone would tell
you to reflow the entire board. Learn to read. Then learn how to
properly comprehend what you read.

You refer to "the entire board". He refers to a PCB, but not the one you
think. The part in question is a PCB in itself. It's a hybrid module with
its own SMT parts, so you can't heat the whole part.

YES, you can, damnit! The key is to PRE-heat the entire part so that
the transition of temperature from that temp to the temp needed to remove
the part is lower, and less likely to reflow only a portion of the pins.
It insures that ALL the pins on the chip reflow, and the chip can be
removed without damaging the PCB.

I never said anything about reflowing the entire PCB. HE DID!

I mentioned PRE-heating the PCB, and then HEATING only the part to be
removed to the reflow temperature.

Google the part number and see what it looks like.