19 May
2010
19 May
'10
9:53 a.m.
Chuck Guzis wrote:
On 18 May 2010 at 8:04, John Robertson wrote:
You didn't quote the entire discussion. If you had you would realize I
was responding to your point of:
----------(quote)------------
Okay, how about masking and painting the missing contact with some
silver- or copper-conductive PCB repair paint, then electroplating a
few mils of copper onto that? Finish with a gold flash and it should
work like the original.
--Chuck
-------------(end quote)------------
My point is that painting a coating and then electroplating copper etc.
is still going to leave a surface that is unlikely to survive the
pressures of being inserted into a card edge connector. Also my
experience with card edge repair power bus connectors leads me to
believe this would not survive any real current (2 - 5 amps) unless the
surface is completely flat - which is very hard to do with the paint up
PCB kits.
In my 30 some years of board repairs (not mil-spec, but commercial grade
- mostly pinball and video game logic boards) I have found that edge
connectors that carry power buses are the most difficult to repair for
long term survival. That is why I use the PACE style replacement tinned
copper sheets - they work. I am sure that other methods exist that works
just as well, but this works for me - and my customers are happy with
boards that run for years between service.
John :-#)#
--
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, VideoGames)
www.flippers.com
"Old pinballers never die, they just flip out"
That won't work for edge connectors - it
would disintegrate under
contact wiping and/or pressure. Particularly if the pad is passing any
current (power rails).
I don't understand why this would be the case. Copper is copper,
whether it's foil glued on or electroplated.
Heck, during the 80's, PCBs that were *all* electrodeposition (no
etching) were widely produced. An electroless copper process formed
the base, which was then electroplated to the desired thickness. PCB
vias are still formed this way.
Thickness isn't an issue--whole parts are sometimes produced by
electrodeposition of copper, far greater than the thickness of the
foil used in PCBs.
Can you offer a cite or some rationale as to why electrodeposited
copper is inferior to foil?
Chuck