Wifi routers and lightning

LoopyByteloose

Does anyone have experience with wifi routers downed by lightning storms?

I have had a wifi router up and running for about two months with good operation. But this week we had a passing typhoon and quite a bit of lightning.

Now it seems to be not well. At first it was slow, but now I cannot seem to log into it. I suppose I can try to reinstall the firmware, but I fear it may be bricked.

LoopyByteloose

Never mind, I have determined the power supply is outputting 2.34volts. So it seems that the wall wart died - either from lightning or another source.

Since the router is hacked (like just about everything I use), I have another community that supports problems with in detail. I should have gone their first, but was rather impulsive. There is a tendency to think that the Parallax Forums are the center of the universe (as they almost are).

xanadu

They always do. Back in my SOHO IT days I used to go around replacing the power supplies when all the other guys said 'you need a new router'. I was also the only one that knew what volts and amps were haha. Don't miss working for those people at all

Usually it never comes back on after the power fails, I think in a lot of cases it's a bad solder joint and when the unit cools the connection opens.

LoopyByteloose

I have an Asus wl500gp wifi router and it especially demands a lot of power 2.5amps at +5 volts. Added to that, the wall warts they included seemed to have a high failure rate. (in fact, I may have prematurely gotten rid of my EEEpc due to a bad wall wart being mistaken for a bad battery pack or bad charge circuit).

The wall wart started to read 5.1 volts under no load. Rather than jury rig a load test, I set up another power supply. But the point is you can't just use a VOM to verify low voltage. The problem may suddenly go away for a while even though the power supply is no good. I have a nice little +5 3amp switcher that I am preparing for a long-term replacement AND it was cheaper than a +5 3amp wall wart.

tobdec

Theres a reason we keep hordes of power supplies and wall warts on hand...I mean shelves. We get alot of lightning here in Ohio so the next day I prepare for a hard days work.

LoopyByteloose

We have a lot of lightning here during typhoon season, but this is the first hit that I am aware of. Maybe the EEEpc wall wart was another hit by lightning, I can't be sure. I gave the unit to a guy that took it into Asus repair and they had him pay for a new power supply and it came back fully operational. But they may have even replaced the mother board and not mentioned it. He has a way of getting something for next to nothing when others would have to pay their way. It went to a good home - his son uses it with the original configuration that was set up specifically for kids.

Nonetheless, I am quite happy to replace the power supply rather than the main device. Though these day, a router/gateway is not that money. Still it is about 200% of what I would have to pay for just the power supply. And I locate my 5 watt 25 ohm resistor for load testing. But since the new switcher is doing find, it is rather redundant to check.

katefdh

you should turn off your wifi router when its not in use .. it will save energy ..!! and many other advantages

tobdec

^ One post and that was it? lol welcome to the forums!

LoopyByteloose

Turn off when not in use. Yes, indeed. The problem stems from being shut in and at home when a typhoon occurs. I am left with nothing to do, but use the computer. For other reasons, It is not really a good idea to leave wifi router on 24/7. They offer interesting targets to budding snoopers and hackers.

Today was trash day - so I ran off to the meeting garbage truck with quite a bit after the long shut in of last week. When I got back, the defective wall wart had escaped from my recycle bag.

Oddly it doesn't have a recycle sticker on it, just one that indicates it doesn't belong in the trash.

Since it was here and I had already cut the +5 cord with barrel plug off it to use with the switcher that replaced, I decided that it was time to do a postmortem. I was very curious to see what was inside that might fail as it was rated at +5VDC regulated and 2.5amps output.

So I hack-sawed a slot in one seam, inserted a screw driver and twisted. It opened up and I immediately see that it did include lightning protect in the form of just one MOV (metal oxide varesistor). These MOV are good for one or two strikes, but not a whole storm system. Plus, the manufacturers tend to use a lower rating and just one. Three and in higher ratings are much more likely to help out.

But the MOV is awkward as it is often difficult to determine if it is good or already damaged. The board itself does not have an burned parts or scorched marks, but is an intricate switcher with two transformers that may have suffered damage to coils.

In sum, no obvious damage, but no obvious means of repair either. And since the MOV may be shot, the unit that DID protect the router may not be able to do so again.

I guess I should install an MOV network on the other switchers AC Mains that has replaced this wall wart, or install one of those CORCOM plugs that has a network of coils and caps that protects against income surges and spikes -- maybe both. At least with the switcher in a metal chassis, I can replace these items if there is evidence that they have been hit.

So now, the remains go into a baggie and are sent off to the recycler to pass on to appropriate disposal channels. Unable to see any markings on the MOV.

There is a kind of burnt electrical smell to the unit's internals.

LoopyByteloose

New information! MOVs are no longer being used without an actual fuse in series. It seems that it finally dawned on the regulators that too many were no longer useful and that LED indicator lights didn't do much to get people to repair or replace damaged MOVs.

And it seems that Gas Discharge Tubes with MOVs are really the best for lightning. But I've no idea where to buy some or how to configure.

At least with having a fuse, the MOV first protects the unit, the fuse protects the MOV; and then the fuse may be replaced for another round of protection. The MOV may slowly wear out, but never do so suddenly and completely.

Erik Friesen

One commonly overlooked thing with surge protectors is that they are relying on ohms law in a 12 or 14 gauge copper wire to lower the voltage. I have bought some that say they need at least 150' of wire from the panel to be effective.

The best is to use an incoming gdt, then mov post 1 ohm resistors, or calculate the ohms to the load. And, yes, a fuse is necessary. One thing to remember with a gdt is that typically they don't release once tripped. I used some 250 volt gdts on a project of mine, and found that normal surges were catching it. I moved up to a 350v gdt, and it is about right for 120v mains.