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solder resin removal

I

ian hagedorn

Jan 1, 1970
0
I have to resolder all the solder joints in a power board for my TV. What
can I use to remove the resin stains when I'm done? No electronics
suppliers for miles around so I was hoping there would be some household or
automotive solvent that would work.

thanks,
gnuman
 
N

NSM

Jan 1, 1970
0
| I have to resolder all the solder joints in a power board for my TV. What
| can I use to remove the resin stains when I'm done? No electronics
| suppliers for miles around so I was hoping there would be some household
or
| automotive solvent that would work.

Try rubbing alcohol. Methylated alcohol is another one to try.

N
 
J

JURB6006

Jan 1, 1970
0
I've found acetone to be much better than any alcohol for this purpose. When
you remove a part you can simply use a Qtip or even a folded up paper towel to
clean the board, but since you're only resoldering it will probably work best
with a stiff paintbrush, you know the cheapo ones. The only thing is that it
must be the type you can use for oil based paint or the acetone might clean the
bristles right off.

Also be careful not to get acetone on plastic, especially cabinet, parts. The
frame the board sits in will probably be OK unless you bathe it in the stuff.
Different types of plastic have different degrees of tolerance for acetone, so
I make it my policy not to let acetone touch any plastic visible to the
customer.

Acetone is available at alot of auto parts stores because it is used as an
automotive paint thinner, or something.

Actually toluene works even better but it has other disadvantages, the worst of
which is that it's very destructive to all but a very few plastics, even the PC
board frame. Eats it like a strong acid. Add to that it's quite a bit more
volaitile (can I get a spell check on that ? my NG reader goesn't have one) and
you might get a bit stoned if you use alot of it, or the customers might think
you are . . . .

JURB
 
G

Guest

Jan 1, 1970
0
: I have to resolder all the solder joints in a power board for my TV. What
: can I use to remove the resin stains when I'm done? No electronics
: suppliers for miles around so I was hoping there would be some household or
: automotive solvent that would work.

: thanks,
: gnuman

Why not just leave the flux on the board? I work in the computer industry
and that's what we do. In fact, attempts to "remove" the flux usually
do two things. 1) They don't really remove the flux, it just spreads
it around and 2) Attempts to dissolve RMA (Rosin, mildly active) flux
typically cause it to be more active and can result in corrosionA

Lastly, I was a TV bench tech before working as an EE and never found
it necessary to remove solder flux.

As for "soldering all connections on the Power Board" I question why
that'd be necessary in the first place.

b.
 
C

CJT

Jan 1, 1970
0
: I have to resolder all the solder joints in a power board for my TV. What
: can I use to remove the resin stains when I'm done? No electronics
: suppliers for miles around so I was hoping there would be some household or
: automotive solvent that would work.

: thanks,
: gnuman

Why not just leave the flux on the board? I work in the computer industry
and that's what we do. In fact, attempts to "remove" the flux usually
do two things. 1) They don't really remove the flux, it just spreads
it around and 2) Attempts to dissolve RMA (Rosin, mildly active) flux
typically cause it to be more active and can result in corrosionA

Lastly, I was a TV bench tech before working as an EE and never found
it necessary to remove solder flux.

I usually use my fingernail to mechanically remove the big gobs (partly
so I can see the joint better to make sure I haven't shorted something),
but other than that, I agree completely. Leave it on.
As for "soldering all connections on the Power Board" I question why
that'd be necessary in the first place.

For sure.
 
C

Charles Schuler

Jan 1, 1970
0
I use ordinary drugstore alcohol and Q-tips. A little flux residue usually
won't hurt anything. However, a glob of burnt flux could be a problem in
high-impedance circuits if it bridges the wrong two points. Also, flux is
sticky and absorbs water so it can collect other materials as time goes on.
There are commercial flux removers and brushes available, if you are looking
for the very best approach.
 
I

ian hagedorn

Jan 1, 1970
0
CJT said:
I usually use my fingernail to mechanically remove the big gobs (partly
so I can see the joint better to make sure I haven't shorted something),
but other than that, I agree completely. Leave it on.

For sure.

Thanks to everyone for the replies. As for why to resolder connections on
the power board, I'm just taking advice from other techs:

"Pioneers are well known for cold solder joints in there main power boards,
with the ones we do here are first step is to resolder this entire board,
then if a problem persist go from there, however a good resolder job will
cure about 2/3 of these Pioneer's".

My SD-P5053 projection will not turn on. I hear the relay turn on, then
off. I've checked all the transistors and diodes. Now I'll follow the
advice of resoldering. I am interested if anyone has any other ideas......

thnx again
 
C

CJT

Jan 1, 1970
0
ian said:
Thanks to everyone for the replies. As for why to resolder connections on
the power board, I'm just taking advice from other techs:

"Pioneers are well known for cold solder joints in there main power boards,
with the ones we do here are first step is to resolder this entire board,
then if a problem persist go from there, however a good resolder job will
cure about 2/3 of these Pioneer's".

My SD-P5053 projection will not turn on. I hear the relay turn on, then
off. I've checked all the transistors and diodes. Now I'll follow the
advice of resoldering. I am interested if anyone has any other ideas......

thnx again
It sounds to me like the protection circuit is being activated. That
might be the result of a cold solder joint, but as likely (IMHO) it
could be a problem in the horizontal output stage (transistor,
transformer, capacitors, etc.).
 
L

Lionel

Jan 1, 1970
0
I have to resolder all the solder joints in a power board for my TV. What
can I use to remove the resin stains when I'm done? No electronics
suppliers for miles around so I was hoping there would be some household or
automotive solvent that would work.

A toothbrush & alcohol (any kind) works fine. But unless you really need
it to look clean, it's better to leave it on, as it shields the joint
from corrosion.
 
B

Bill Jeffrey

Jan 1, 1970
0
ian said:
I have to resolder all the solder joints in a power board for my TV. What
can I use to remove the resin stains when I'm done? No electronics
suppliers for miles around so I was hoping there would be some household or
automotive solvent that would work.

In the old days (60's and 70's), every tech station at the MIL companies
I worked for was equipped with a pint pot of MEK and a small stiff
short-bristle brush. Techs were always told to use plenty of MEK -
enough that it runs off the board - so as to avoid leaving a flux
residue behind when the MEK evaporated.

MEK is still available in most states, though you may have to buy a
gallon can of it. Check the paint dept of Home Depot, etc. I would
suggest plenty of ventilation, although we didn't pay much attention to
it then.

MEK = methyl-ethyl ketone

Bill
 
N

NSM

Jan 1, 1970
0
....
| MEK is still available in most states, though you may have to buy a
| gallon can of it. Check the paint dept of Home Depot, etc. I would
| suggest plenty of ventilation, although we didn't pay much attention to
| it then.
|
| MEK = methyl-ethyl ketone

I believe it's toxicity is known:-

"Methyl ethyl ketone is used as a solvent. Acute (short-term) inhalation
exposure to methyl ethyl ketone in humans results in irritation to the eyes,
nose, and throat. Limited information is available on the chronic
(long-term) effects of methyl ethyl ketone in humans. Chronic inhalation
studies in animals have reported slight neurological, liver, kidney, and
respiratory effects. No information is available on the developmental,
reproductive, or carcinogenic effects of methyl ethyl ketone in humans.
Developmental effects, including decreased fetal weight and fetal
malformations, have been reported in mice and rats exposed to methyl ethyl
ketone via inhalation and ingestion. EPA has classified methyl ethyl ketone
as a Group D, not classifiable as to human carcinogenicity."

N
 
Z

Zotin Khuma

Jan 1, 1970
0
CJT said:
I usually use my fingernail to mechanically remove the big gobs (partly
so I can see the joint better to make sure I haven't shorted something),
but other than that, I agree completely. Leave it on.

For sure.
Solder flux is mildly corrosive to copper, though I haven't seen any
serious damage done to the copper tracks myself.

Fingernail, toothpick, plastic screwdriver.... I use them myself to
remove most of the flux after it's cooled and become crumbly, then
clean the rest with car paint thinner. Methylated spirit dissolves
flux too but thinner's much stronger. I use cotton-wool soaked with
thinner and squeezed to get most of the excess thinner out so that it
won't run and spread the flux.

Some production batches have so many cold and dry solder joints that
it's virtually impossible to detect all bad joints individually. A
poor joint may not be causing any symptoms right now, but could show
up a day or a month later.
 
S

Sam Goldwasser

Jan 1, 1970
0
Rubbing alcohol works just fine. No need for noxious chemicals. :)

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Important: Anything sent to the email address in the message header is ignored.
To contact me, please use the feedback form on the S.E.R FAQ Web sites.
 
J

Jason D.

Jan 1, 1970
0
...
| MEK is still available in most states, though you may have to buy a
| gallon can of it. Check the paint dept of Home Depot, etc. I would
| suggest plenty of ventilation, although we didn't pay much attention to
| it then.
|
| MEK = methyl-ethyl ketone

I believe it's toxicity is known:-

"Methyl ethyl ketone is used as a solvent. Acute (short-term) inhalation Snip
ketone via inhalation and ingestion. EPA has classified methyl ethyl ketone
as a Group D, not classifiable as to human carcinogenicity."

N

Yes, the Ketone in that caused my father's liver to fail, died 59 last
July. He worked for nylon manufacturer (Celanse sp?).

Cheers,

Wizard
 
A

Asimov

Jan 1, 1970
0
"Sam Goldwasser" bravely wrote to "All" (09 Nov 04 19:35:12)
--- on the heady topic of "Re: solder resin removal"

SG> From: Sam Goldwasser <[email protected]>

SG> Rubbing alcohol works just fine. No need for noxious chemicals. :)

I heard say lemon juice works as flux remover too but I've never tried
it. Hmmm, I think ethyl would work too. Maybe a little lemon schnapps
might work then and any left over would be fit to drink. That isn't
too noxious and helps pass the time... I little swig for me, a little
swig for the pcb, a little swig for the boss's wife, a little swig for
the... hick!!!

A*s*i*m*o*v

.... Dr.Ruth: Sex onn TV iss okay...aas lonng as vyou don'ts fahll hofff.
 
H

H. R. Bob Hofmann

Jan 1, 1970
0
Yes, the Ketone in that caused my father's liver to fail, died 59 last
July. He worked for nylon manufacturer (Celanse sp?).

Cheers,

Wizard

I use Naptha as a general purpose cleanser.

H. R.(Bob) Hofmann
 
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