13 Sep
2013
13 Sep
'13
10:30 a.m.
On Fri, Sep 13, 2013 at 12:47 PM, Jim Beacon <jim at g1jbg.co.uk> wrote:
Ethan,
my first move would be to get rid of the socket!
It's not my first move. ;-)
It is extremely difficult to solder a socket to a
multilayer board, unless
it is part of the original flow solder process, and if some of the holes are
not through plated (or have lost the plating during previous repairs), the
socket will often only make contact with the tracks on one side of the
board.
I have seen exactly what you describe, and since I did not remove
the original chip or install the socket, I was immediately suspicious.
I have visually inspected the socket and traces, from above and
by shining light through and by direct electrical test. I've even
cleaned and reflowed the pins. The connection seems good.
This used to be a problem on a number of pieces of
equipment that I used to
look after, and I often found myself repairing faults that had been
generated by the use of IC sockets for repairs.
While I'm sure that's all true, I've never had problems with the use
of high-quality sockets, installed by an expert.
It's not just this bit. This bit is either all-on (if installed) or all-off
(if the chip is missing), *and* there are video artefacts at another
bit position. It's not _just_ a Sad Mac, hex code, and jail bars.
-ethan