28 Jan
2009
28 Jan
'09
10:13 a.m.
Recently, I've run across some circuit boards with damaged connector fingers. Some are
badly scratched and worn, the gold plating almost gone, and others are actually corroded -
the copper has corroded, possibly due to previous damage to the gold plating.
The circuit boards in question are the ones in Nintendo cartridges, but the same problem
applies to any printed circuit board edge connector.
The scratched/worn connectors seem to still work, at least most of the time. The corroded
ones wouldn't work until I cleaned off the corrosion. Not an easy thing to do - I
ended up resorting to Brasso, a brass polish. Now, this is NOT the thing to use to clean
edge connectors! DON'T DO IT! It WILL take the plating off. In this case, the plating
was already gone, and the copper track underneath was corroded. Cleaning the corrosion off
with the Brasso, and subsequent cleaning with alcohol to clean off the Brasso, removed the
corrosion leaving a shiny copper track. The board worked fine, but for how long? How long
until the corrosion comes back, or the copper oxidizes?
Is there any way to repair or replate fingers like this? Obviously, tinning them with
solder would prevent oxidization, but this would make that 'finger' much too
thick, and risks damaging the connector it plugs into. (Operators loved to "fix"
burnt edge connectors on arcade boards like this, and it works for a while, until you go
to unplug and replug it, and the destoyed connector no longer mates with the board
correctly.)
Just something I thought that others might have an input on - I mean, in this case, these
Nintendo cartridges are not worth the effort of any complicated repair, but it raised the
question in my mind, and I know I've run into this on computers before.
So, any thoughts?
-Ian
28 Jan
28 Jan
10:39 a.m.
On 28 Jan 2009 at 10:13, Mr Ian Primus wrote:
Is there any way to repair or replate fingers like
this? Obviously,
tinning them with solder would prevent oxidization, but this would
make that 'finger' much too thick, and risks damaging the connector it
plugs into. (Operators loved to "fix" burnt edge connectors on arcade
boards like this, and it works for a while, until you go to unplug and
replug it, and the destoyed connector no longer mates with the board
correctly.)
Yes, there is a way to refurb the plating. See:
http://caswellplating.com/kits/plugnplate.htm
Small, fairly inexpensive kits for brush plating.
Cheers,
Chuck
11:07 p.m.
Yes, there is a way to refurb the plating. See:
http://caswellplating.com/kits/plugnplate.htm
Small, fairly inexpensive kits for brush plating.
This is great, but the current applied may not be good for the
integrated circuits on board...
29 Jan
29 Jan
1:11 a.m.
On 29 Jan 2009 at 5:07, Alexandre Souza wrote:
The way this thing works is that the surface to be plated is
connected to the negative side of the low-voltage supply and the
brush/cathode is connected to the positive side. I'd probably tack a
thin wire (or use some conductive ink) across the entire span of
contacts for the plating process and then remove it when finished.
There should be no appreciable current induced in any circuit
element.
Pretty much any other process is going to remove some of the copper
contacts. One could even use electroplating to build up the copper
on the contacts before electroplating a noble metal.
Cheers,
Chuck
Yes, there is
a way to refurb the plating. See:
http://caswellplating.com/kits/plugnplate.htm
Small, fairly inexpensive kits for brush plating.
This is great, but the current applied may not be good for the
integrated circuits on board... 
28 Jan
28 Jan
11:04 a.m.
Mr Ian Primus wrote:
Recently, I've run across some circuit boards with
damaged connector fingers. Some are badly scratched and worn, the gold plating almost
gone, and others are actually corroded - the copper has corroded, possibly due to previous
damage to the gold plating.
The circuit boards in question are the ones in Nintendo cartridges, but the same problem
applies to any printed circuit board edge connector.
The scratched/worn connectors seem to still work, at least most of the time. The corroded
ones wouldn't work until I cleaned off the corrosion. Not an easy thing to do - I
ended up resorting to Brasso, a brass polish. Now, this is NOT the thing to use to clean
edge connectors! DON'T DO IT! It WILL take the plating off. In this case, the plating
was already gone, and the copper track underneath was corroded. Cleaning the corrosion off
with the Brasso, and subsequent cleaning with alcohol to clean off the Brasso, removed the
corrosion leaving a shiny copper track. The board worked fine, but for how long? How long
until the corrosion comes back, or the copper oxidizes?
Is there any way to repair or replate fingers like this? Obviously, tinning them with
solder would prevent oxidization, but this would make that 'finger' much too
thick, and risks damaging the connector it plugs into. (Operators loved to "fix"
burnt edge connectors on arcade boards like this, and it works for a while, until you go
to unplug and replug it, and the destoyed connector no longer mates with the board
correctly.)
Just something I thought that others might have an input on - I mean, in this case, these
Nintendo cartridges are not worth the effort of any complicated repair, but it raised the
question in my mind, and I know I've run into this on computers before.
So, any thoughts?
-Ian
I ran across these guys a few weeks back. They have a number of
interesting procedural references on all kinds of circuit board repair.
They sell a full line of repair and rework supplies, but they are
'professional' quality (meaning reasonably high cost). I haven't used
their stuff (yet) but am keeping the info around as you never know.
Website: http://www.engineeringlab.com/
Don
11:12 a.m.
Mr Ian Primus wrote:
Recently, I've run across some circuit boards with damaged connector fingers. Some
are badly scratched and worn, the gold plating almost gone, and others are actually
corroded - the copper has corroded, possibly due to previous damage to the gold plating.
...
The scratched/worn connectors seem to still work, at least most of the time. The corroded
ones wouldn't work until I cleaned off the corrosion. Not an easy thing to do - I
ended up resorting to Brasso, a brass polish. Now, this is NOT the thing to use to clean
edge connectors! DON'T DO IT! It WILL take the plating off. In this case, the plating
was already gone, and the copper track underneath was corroded. Cleaning the corrosion off
with the Brasso, and subsequent cleaning with alcohol to clean off the Brasso, removed the
corrosion leaving a shiny copper track. The board worked fine, but for how long? How long
until the corrosion comes back, or the copper oxidizes?
Is there any way to repair or replate fingers like this? Obviously, tinning them with
solder would prevent oxidization, but this would make that 'finger' much too
thick, and risks damaging the connector it plugs into. (Operators loved to "fix"
burnt edge connectors on arcade boards like this, and it works for a while, until you go
to unplug and replug it, and the destoyed connector no longer mates with the board
correctly.)
Just something I thought that others might have an input on - I mean, in this case, these
Nintendo cartridges are not worth the effort of any complicated repair, but it raised the
question in my mind, and I know I've run into this on computers before.
There is a dip solution one can purchase that does a nickel plate. The bottle
is covered in toxic/hazardous/poisonous/special-discard-procedure warnings,
however. Never used it, I've just seen it a store.
Along simpler lines though, it is possible to leave a very thin solder plate on
the bare copper by tinning it, and having a cloth or slightly damp sponge at
the ready to immediately wipe off the excess solder. Some skill or practice may
be required but it can/will leave just a 'plating', thin enough to be
inconsequential to the edge connector receptacle.
On the other hand, I have bare-copper PCBs with edge connectors I built as a
kid in the 70's that still have no corrosion and are still functioning with no
problems. YMMV with climate I suppose.
11:26 a.m.
Brent Hilpert wrote:
There is a dip solution one can purchase that does a nickel plate. The bottle
is covered in toxic/hazardous/poisonous/special-discard-procedure warnings,
however. Never used it, I've just seen it a store.
Whoops, should have said tin plate:
http://www.mgchemicals.com/products/421.html?PHPSESSID=3ccbef3cfd59dc42022d…
The above is a Canadian source, shipping to other jurisdictions may be an issue.
4:11 p.m.
On 28 Jan 2009 at 11:26, Brent Hilpert wrote:
Whoops, should have said tin plate:
http://www.mgchemicals.com/products/421.html?PHPSESSID=3ccbef3cfd59dc42022d…
The above is a Canadian source, shipping to other jurisdictions may be an issue.
Datak also sells a relatively inexpensive tinplating kit:
http://www.cir.com/parts/prntcirc/prntcirc.htm#tin
And I believe that Datak sells something called "Liquid Tin" along
the same lines. I've used the Datak stuff quite a bit to finish bare
copper boards.
Cheers,
Chuck
11:52 a.m.
On Wed, 28 Jan 2009, Mr Ian Primus wrote:
The scratched/worn connectors seem to still work, at
least most of the
time. The corroded ones wouldn't work until I cleaned off the corrosion.
For cleaning copper contacts, I like DeOxit. Any well equipped guitar
shop should carry it (part of the Hosa line).
Mike Loewen mloewen at cpumagic.scol.pa.us
Old Technology http://sturgeon.css.psu.edu/~mloewen/Oldtech/
11:04 p.m.
Is there any way to repair or replate fingers like
this? Obviously,
tinning them with solder would prevent oxidization, but this would make
that 'finger' much too thick, and risks damaging the connector it plugs
into. (Operators loved to "fix" burnt edge connectors on arcade boards
like this, and it works for a while, until you go to unplug and replug it,
and the destoyed connector no longer mates with the board correctly.)
Use good quality solder and remove it with solder braid, it will look
like hot-air-leveling.
11:12 p.m.
On 29 Jan 2009 at 5:04, Alexandre Souza wrote:
Use good quality solder and remove it with solder
braid, it will look
like hot-air-leveling.
Or you could use one of the silver ion-exchange plating solutions and
(very thinly) coat the copper with a layer of silver.
Anyone remember "Cool Amp"? They're still around:
http://www.cool-amp.com/
Cheers,
Chuck
29 Jan
29 Jan
6:34 a.m.
--- On Thu, 1/29/09, Alexandre Souza <alexandre-listas at e-secure.com.br> wrote:
Use good quality solder and remove it with solder
braid,
it will look like hot-air-leveling.
Hmm, I hadn't thought of that. I know I've tried in the past on junk boards, and
never was able to get the solder smooth and level enough to make it the same as the
surrounding fingers. I usually don't use solder braid, so I didn't think of that.
I'll have to try it when I get a chance, but I still would worry that it would make
that connector finger too thick.
I like the other ideas about electroplating and small-scale plating kits. That might be an
option if I really need to fix something that's worth that much time and effort.
With the arcade boards, I can tell you the solution I've seen used. It's ugly as
hell, but it works. Basically, with some boards, like Pac-Man especially, the tin
connector fingers get burnt and badly pitted. After that, even a new female connector
won't mate well or work. Tinning them with solder makes them too thick and damages the
connector, and sometimes there's not even enough of a contact left to re-tin.
Basically, the solution there is to solder a female connector directly onto the male
fingers of the board - so the board now sports a female socket that male fingers can be
plugged into. Then you take a 'fingerboard' - a thin bit of circuit board with
long fingers on it and nothing else, and plug it into the female socket - and now you can
plug the arcade cabinet's female socket onto that. Again, ugly, but very functional,
and sometimes the only way to save a badly damaged board.
This is totally unacceptable most times in computers - not only would finding the
connectors be a pain, but this would make the board too long, and it wouldn't seat
properly into a backplane, etc.
I'll definitely try using solder braid to remove solder on a finger, and see if I can
get close to the same thickness. Maybe if you were to mask off the nearby fingers and
carefully sand down the solder, you could get it even thinner? I'd be worried about
burrs and bumps in the solder that could damage the female connector that it mates with.
And it's good to know that replating kits exist - I just wonder - has anyone ever
actually used these to fix circuit board fingers? How does it work in this application?
I'd be worried about the durability of the plating, and getting a consistent
thickness.
-Ian
12:49 p.m.
Mr Ian Primus wrote:
--- On Thu, 1/29/09, Alexandre Souza <alexandre-listas at e-secure.com.br> wrote:
...
Use good quality solder and remove it with
solder braid,
it will look like hot-air-leveling.
Hmm, I hadn't thought of that. I know I've tried in the past on junk boards, and
never was able to get the solder smooth and level enough to make it the same as the
surrounding fingers. I usually don't use solder braid, so I didn't think of that.
I'll have to try it when I get a chance, but I still would worry that it would make
that connector finger too thick. I'll definitely try using solder braid to remove
solder on a finger, and see if I can get close to the same thickness. Maybe if you were to
mask off the nearby fingers and carefully sand down the solder, you could get it even
thinner? I'd be worried about burrs and bumps in the solder that could damage the
female connector that it mates with.
The previously-mentioned quick wipe with a cloth or sponge may leave a thinner
and smoother surface than using solder braid.
Secure the PCB so it doesn't move, soldering iron in one hand, cloth/sponge
poised next to the area to be wiped in the other hand. Dry cotton cloth or
warm, lightly damp cloth or sponge.
5758
days inactive
5759
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12 comments
6 participants
participants (6)
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ak6dn＠mindspring.com -
alexandre-listas＠e-secure.com.br -
cclist＠sydex.com -
hilpert＠cs.ubc.ca -
ian_primus＠yahoo.com -
mloewen＠cpumagic.scol.pa.us