Date   : Sun, 10 Oct 2010 17:20:30 +0100
From   : profpep@... (Mike Pepper)
Subject: [OT] ADSL router fried?

On the hardware side, here's the telephone line input:
   http://www.heyrick.co.uk/blog/images/20100912adsl.jpeg

What should I check here? What's the white thing, filter capacitor?
Failsafe crowbar?

White thing is a gas filled spark gap voltage protector. They contain a a
gas mixture that breaks down and conducts at a higher voltage than the usual
varistor, but only quenches at a significantly  lower voltage than the
strike potential. There to protect against minor lightening induced line
currents, (very little will stop a main strike - 2.5mm wire opens like a
small fuse at those currents, you'l know if you've copped on of those - most
of the rig will be dead).

If you think there might be a line fault like that, check the input pair for
continuity, and also for shorts - minor lightening damage can cause various
forms of tracking downstream of the cricuit protection

HTH

||\/||ike