What happens to hub if plugged into ethernet port accidentally?

[jkcunningham]

I was troubleshooting a PC on my way-overcrowded workbench and grabbed what I thought was a spare ethernet cable from an 8-port router I keep sitting there for that purpose. Unfortunately, it was actually, a spare wire plugged into my 6-port master 1-wire hub that I had just unplugged from a test board the night before (same color). Lame, lame, lame... I didn't discover my mistake until I debugged why the PC networking wasn't working.

The 1-wire hub was powered with 15-volts, as it has a barometer among its client boards. There was no damage to the ethernet port on the PC which worked fine once I put the correct cable in place and restarted eth0.

However, the OWFS system went down from the moment of the misconnection on and shows no sign of life. The led's on the hub show no sign of life (though they were never consistently on before, so I'm not sure that is necessarily significant).

My question is: did I kill it? Is it fatal?

I looked at the wiring diagram and it didn't look like anything catastrophic would happen, but here I have my reality.

Any ideas?

Jeff Cunningham

 

[jkcunningham]

I answered my own question by taking it apart. A couple traces are fried between the 12v regulator and the 8-pin DS2408 chip right next to it.
I think I might have a replacement chip around here, but I wonder if its worth the trouble to replace it? A lot more could have been taken out along with it.

Jeff

 

[jkcunningham]

FWIW: It wasn't that hard to fix. I had to replace the diode in the 12v path and the DS2408 chip and replace the burned trace with a piece of wire.

Three people pointed out to me that this is why its always a bad idea designing interfaces using common connectors in ways which aren't compatible with the way they are normally wired. :-(
Jeff

 

[felixrosbergen]

Tell that to ELK and their databus hub.....

Maybe putting color coded boots on the RJ45's would be a good idea...if i hadn't already done the terminations... :hesaid:

Anybody seen feed through RJ45 connectors for Cat6? I use the EZRJ45 and they're awesome..

 

[BLH]

I have seen users of the Smarthome Insteon PLM 2412S; PLC 2414S and older 1132B Serial controller damage network stuff. They also have an RJ45 connector on them and have a raw +12 volts supply on the pins.

 

[drozwood90]

Ethernet relies on current, not voltage. So, you get a SHORT across the pairs when you "look" at the pairs using a meter (there's a transformer to isolate the board).

That's why you saw the dead part on your 1-wire.

--Dan