In article , Paul wrote:
Norm X wrote:
On 2015-12-27 5:36 PM, Norm X wrote:
Hi,

This is Xposted.

After upgrading to cat6 Ethernet cable and Gigabit Ethernet switch, I am
still having problems with an Ethernet connection that craps out at 1.0
Gbps. Also at the same time, the filesystem connection to a 64 GB
microSD (xSDHC) also craps out. The microSD is mounted in a an SDHC
adapter. From my experience, I am inclined always to first suspect
hardware fault.

You changed both the switch and cable; the problem did not change, so
it'sprobably not the hardware. Are you seeing any error messages in the
Event Logs?
So as is my usual technique, I cleaned the contact of
the microSD and its adapter first by rubbing with a pink pencil eraser

Be careful with that; modern connectors have a very thin layer of gold
compared to twenty years or more ago. It's easy to damage the coating
with abrasive cleaning.

and then with 70% isopropyl alcohol on a Qtip and then a dry Qtip.
Neither the pink eraser nor the Qtip showed a grey stain as is common
with oxidation. I also tried to clean the Ethernet connector

Since I started writing this, 1.0 Gbps connection has crapped out once
but now it is re-established. The file system connection to the 64 GB
microSD has held steady.

Comments?

Try disconnecting the microSD and adapter and see if the network becomes
stable.

Thanks.


Now both are crapped out. Good thing I also have WiFi.

A quick glance at the RJ-45 on my Acer laptop, shows 10u gold
plated contacts.

A look at my Ethernet cable, shows 10u gold on the contacts
on it as well. And my cable has a plastic block with channels
to guide the contacts on the cable end, so they cannot move.
Only the laptop end uses "beams" that could be displaced
if too much force is used.

Generally, you want gold-on-gold or tin-on-tin, when mixing
connector types. Gold on gold slides, tin on tin bites.
Mixing gold and tin would not work well, and it's possible
if you examine more pairs of RJ-45s you'll find they're
using gold.

All RJ-45 plugs will be gold plated; otherwise they wouldn't be
compliant with the Cat5 or Cat 6 specs.

I do not recommend pink pencil eraser for gold plated
finishes. The computer industry uses 10u gold, while
telecom parts use 50u gold. No matter what the thickness,
a poorly administered gold application can have pinholes.
Or, if improperly masked some portions may not get any
gold at all. Parts should be rejected, if the gold application
is not done properly.

Gold is not applied directly over copper. There is an electroplate
sequence, with the right materials coming in contact with
one another, to achieve the best plating finish and
performance over time.

When the motherboard PCB is on the soldering line, one
of the steps after double-IR reflow is completed, is
the wash cycle. The Ethernet connector on your laptop
has a rubber bung inserted in the connector, which
serves to keep wash water out of the connector. The wash
cycle removes water soluble solder flux. If the bung
is not water tight, or if no bung was used at all,
the washing machine can cause a little bit of flux to
coat the nicely prepared 8 gold plated contacts
in the RJ-45.
[...]

I'm leaning towards a bad driver or IRQ conflict. Checking Event Log
would be a good place to look for more clues.


Gary