Re: Keypad problem ?


Joe Zeglinski
 

Thanks Dominik,

Are there two PCB's inside - one is the keypad, and the other, the
processor and display? I think Marj may be wondering if you had a problem just
with the keypad PCB ( which is made by another supplier), or the processor
PCB, if there is more than one board inside.

The picture will put everyone's mind at rest - or maybe something to watch out
for, in future. Anyway, it will help all of us, with a potential problem
someday.

Thanks, and dobra noc,
Joe

----- Original Message -----
From: "Dominik Wos" <dominik@derpal.com.pl>
To: <ap-gto@yahoogroups.com>
Sent: Tuesday, April 17, 2007 7:08 PM
Subject: [ap-gto] Re: Keypad problem ?


Hi Joe,

OK, I will once again dismantle the keypad to take some pictures and
will post them on the Group. You will see the repair and what is
inside the keypad.

All the best,
Dominik

--- In ap-gto@yahoogroups.com, "Joseph Zeglinski" <J.Zeglinski@...>
wrote:

Hi Dominik,

Glad to hear that all is well, after the fix.

For the rest of us, perhaps, you could clarify, just in case we
run into a
similar problem. In anticipation of other's questions, (Marj was
not quite
clear on your post), perhaps we have a very slight misunderstanding
in
translation - when you mention "silver" traces.

I have never seen "silver" used in PCB contacts or traces on
circuit
boards - they are either gold plated or beryllium plated contacts,
and circuit
traces were, until recently perhaps, always lead/tin solder. I
wonder where
the "silver" comes in to play. Unless, silver is being used somehow
to replace
solder, in order to meet Europe's ROHS pollution standard - an
expensive
solution, but this board likely predates that requirement.

Also, circuit traces, even if they are the "old solder
standard", are
almost always covered by a green layer of protective "conformal
coating", on
good quality circuit board products, which must be standard for
Astro Physics
products, surely.

So, I don't quite understand where your friend found
anything "silver". Is
it possible that he is using our Polish term "srebny", which
describes things
that are "silver coloured", in referring to the "colour" of solder
(traces)?
Even so, I am surprised he could get to the solder trace without
some effort
to scrape away the green conformal coating, painted over it.

Be that as it may, it would appear that there was a possible
bad spot in
the "wave soldering" of the board, leaving a short segment of the
original
"copper trace" on the etched PCB exposed, which obviously has
corroded over
the last 5 years, or more. This break in the trace caused a loss of
some
signal in the Keypad circuit, which your friend expertly cleaned
and
resoldered - he has a good eye to have spotted it. Now everything
is operating
normally.
If so, I wonder about the quality checks made by the original
keypad
manufacturer.

Have I got this right?

Anyway, I probably just made a short story ... long ;-)
Best regards,
Joe (a.k.a. Jozef)


----- Original Message -----
From: "Dominik Wos" <dominik@...>
To: <ap-gto@yahoogroups.com>
Sent: Tuesday, April 17, 2007 5:27 PM
Subject: [ap-gto] Re: Keypad problem ?


Czesc Jozefie,

U mnie wszystko OK. Dzieki :-)

So where the problem was ? According to my neighbour the plastic
keypad which is inside is very sensitive to corrosion (he
manyfactures electronics for agiculture machines and uses this
kind
of products). The paths are made from silver. Accourding to him
it is
a rather common problem esspecialy that I bought my mount second
hand
and I belive it is 2002.



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