[BBC-Micro] [OT] ADSL router fried?

Rick Murray rick at rs432.net
Sun Oct 10 19:32:28 BST 2010


Thanks to those who replied. Having a deeper inspection (glasses off, 
mag glass, bright LED torch...) shows either side of the glass bubble is 
surrounded either side by 0 ohm resistors. The one on the right (looking 
from line socket) has a sign of "pffft" by it, as if some of the magic 
smoke escaped, but it is still operational.
The one on the left? Destroyed.
You can, actually, see them both in that photo:

I have removed the blown resistor and put a solder blob in its place. I 
figure that will suffice as it isn't to be my primary router.

Now, both traces of the line input are intact as far as the transformer 
(black square thing in the photo). I'm not sure what happens beyond...

Don't get your hopes up just yet. There's a blown capacitor by ethernet 
socket #3. My guess is, since this unit is powered from a power brick 
with no ground plane, that a surge entered via the phone line. At some 
stage inside jumped to the earth rail (either someplace in protection 
circuitry... inside the main IC? who knows. The current will be looking 
for the easiest route to earth which is not inside the router. With a 
bit of luck (given the router is mostly functional) it left most of it 
alone. Instead it hit paydirt on the ethernet plug, travelled down the 
wire to an earthed metal box. Most likely fried his network card if it 
was cheapo. His computer ought to be intact as I would hope the current 
would then be dissipated via the backplane to the chassis. But if he's 
one of these morons that never bothers to screw the things in place...

Well, that's my theory.

Will this enable life to be coaxed from the ADSL link? Later (tonight? 
tomorrow?) I'll jack it into the phone line (conveniently 3&4 wired (not 
5&6 as it ought to be!) so I can just whip the lead out of the 
Livebox... I'll post an update then.

By the way, for those who replied to the power line interference 
problem, I now have video of the horrid noise coming in through the 
electrics.... only this time I hit the big switch. It goes a little bit 
quieter (as the trip switches and meter etc are now out of circuit) but 
it is still plenty noisy. Should be sufficient to prove whatever this 
is, it ain't *US*. Mmm too lazy to hook up the OSD right now. When I do, 
I'll digitise the video and toss it over to YouTube, then write some 
pointless prattle (my speciality!) on the b.log. <grin>

Thanks again to all who provided help and info.

Best wishes,


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