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Cat6a blowing modems?

Posted: Thu Mar 14, 2019 7:18 am
by Jbob
Hello all,

I recently purchased a pack of cat6a Ethernet cables to upgrade my wired home network. In the past 24 hours, two of my modems have blown. They worked fine for a short period, then just shut off. Now they do not power up at all. Is it possible for the Cat6a cable to short out a modem?

Modem 1 - Arris SB6190
Modem 2 - Motorola (Arris) SB6141

Cat6a cable - https://www.amazon.com/Cable-Matters-Sn ... th=1&psc=1

Re: Cat6a blowing modems?

Posted: Thu Mar 14, 2019 1:11 pm
by IamJohn
Is it possible? Well, anything is possible but assuming that the manufacturer adhered to the standards and the cables are straight through [as opposed to crossover] cables there is no reason that they should have caused the issues. CAT 6 just has more stringent specs, shielding than CAT 5.
https://en.wikipedia.org/wiki/Category_6_cable

You may just have run into a bit of bad luck with the modems both deciding to die about the same time, a voltage spike, a momentary power outage that came back really quickly and messed up the hardware/firmware on the modems, or something of that sort.

Re: Cat6a blowing modems?

Posted: Thu Mar 14, 2019 1:29 pm
by qbit
a momentary power outage that came back really quickly and messed up the hardware/firmware on the modems, or something of that sort.
Is there a surge protection installed ? How were the atmospheric weather conditions (thunderstorms etc ..) at the time when the defects occurred?
Just a similar thought as that above.

Re: Cat6a blowing modems?

Posted: Thu Mar 14, 2019 5:10 pm
by Jbob
Anything is possible, that’s for sure. No lightning in the area. No surge protector either. I was wondering if there was a spike in the electric current. I Think I read somewhere that the Arris modems can be touchy with fluctuations in electricity. Think I will put the new modem on a surge protector.

Re: Cat6a blowing modems?

Posted: Thu Mar 14, 2019 11:58 pm
by haleakalas
I am not familiar with the modems that you mentioned, but if they have external power supplies, like wall mount plugs, they would be the first ones to go in the event of any troubles with the power. Where I live after each storm I have to replace a bunch of those power adapters, but it rarely happens that the problem reach the actual devices (phones, tablets, electronic gadgets).
As for the network cables, they might contribute to zapping your devices if they have water condensation on them and they are hit by lightening. Very rare though.

Re: Cat6a blowing modems?

Posted: Fri Mar 15, 2019 5:55 am
by lsemmens
Acually haleakayas, Lightning can, and does perform all sorts of weird and wonderful effects on technology.

Back when I was working for a living, I had to go out and provide a temporary telephone service for a customer who had been hit by lightning. When the first tech had gone out to install a phone, lightning hit the same cable again as he was screwing the new phone to the wall. He returned to Darwin in an ambulance. I had to finish his job. The office was about 5m across. There was a black line up the wall where the cable had entered the building and the distribution strip was a black mass. The switchboard operator, sitting on the opposite side of the room had a bandage on her head where the cover had hit her. FYI Darwin has the highest number of Thunderdays of any capital city in the world.

Any electronics is at risk in a thunderstorm. Good surge suppression is good insurance.

The building next door suffered a direct strike. At the time one of my kids was playing a game on a Sega megadrive (that's how long ago it was) and felt a slight electric shock. Another was using a computer (8086 CPU) in the living room. The computer was the only thing with good surge suppression. In the end, all I had to do was replace numerous light globes, the computer went into re-boot, and the TV to which the Sega was connected needed a fuse replaced. The school next door had to have the Airconditioning system repaired along with many other electronic devices.

Back to your modems. It could easily be a power surge causing issues either on the power line or the telephone line.

Re: Cat6a blowing modems?

Posted: Fri Mar 15, 2019 6:14 am
by catweazel
Jbob wrote:
Thu Mar 14, 2019 7:18 am
Hello all,

I recently purchased a pack of cat6a Ethernet cables to upgrade my wired home network. In the past 24 hours, two of my modems have blown. They worked fine for a short period, then just shut off. Now they do not power up at all. Is it possible for the Cat6a cable to short out a modem?
It's highly unlikely. Merely running the cables too close to a refrigerator is sufficient to induct high current into the network when the refrigerator switches its compressor on or off.

Re: Cat6a blowing modems?

Posted: Fri Mar 15, 2019 7:54 am
by Jbob
catweazel wrote:
Fri Mar 15, 2019 6:14 am

It's highly unlikely. Merely running the cables too close to a refrigerator is sufficient to induct high current into the network when the refrigerator switches its compressor on or off.
The modem and router share the same wall as the refrigerator. They are just opposite of each other...I contacted the company about the cables and I am sending this batch back and they are going to replace them. Once they receive these ones back they will run some tests on them to try and see if anything is wrong.

Re: Cat6a blowing modems?

Posted: Fri Mar 15, 2019 7:57 am
by catweazel
Jbob wrote:
Fri Mar 15, 2019 7:54 am
catweazel wrote:
Fri Mar 15, 2019 6:14 am

It's highly unlikely. Merely running the cables too close to a refrigerator is sufficient to induct high current into the network when the refrigerator switches its compressor on or off.
The modem and router share the same wall as the refrigerator. They are just opposite of each other...I contacted the company about the cables and I am sending this batch back and they are going to replace them. Once they receive these ones back they will run some tests on them to try and see if anything is wrong.
My intuition told me and I almost posted that if the power points are on the same circuit as a refrigerator then you may have found your culprit. I mistakenly stopped myself by mistakenly convincing myself the likelihood was low ;)

Re: Cat6a blowing modems?

Posted: Fri Mar 15, 2019 11:15 am
by Jbob
I understand it can happen at anytime, but the modem & router have been there for years with out any issues. Unfortunately I only have the one cable drop for hook up to the internet. I could add a new drop I suppose to get it away from that circuit. Would a decent surge protector be enough to buffer any irregularities such as that?

On another note, I decided to try using a spare power supply on the main modem to see if it would power up and as soon as I plugged it in to the modem, the power supply sizzled and gave off that lovely scent associated with the death of an electronic.

Re: Cat6a blowing modems?

Posted: Fri Mar 15, 2019 11:57 am
by IamJohn
Sizzle from electronics is never good. Check the circuit but do so by trying something simple first: plug in a light or a radio you do not care about into that wall socket. If they don't sizzle, check voltage with a VOM and if it is OK see and if it fluctuates. I hesitate to say check out the fuse/breaker panel but if you are comfortable with that and competent, look there too.

In terms of spikes etc. I would suggest getting a UPS rather than just a power bar with surge protection. The UPS can both filter the current and absorb a larger spike than your typical power bar.

Re: Cat6a blowing modems?

Posted: Fri Mar 15, 2019 1:09 pm
by AndyMH
I'd also recommend a UPS as a buffer and it comes with additional benefits.

Re: Cat6a blowing modems?

Posted: Sat Mar 16, 2019 9:35 am
by Jbob
Thanks all for the input and feedback. New cables and modem are on the way. Will look into getting a UPS for that area as a buffer to future problems.

Re: Cat6a blowing modems?

Posted: Sat Mar 16, 2019 12:19 pm
by IamJohn
Jbob wrote:
Sat Mar 16, 2019 9:35 am
Thanks all for the input and feedback. New cables and modem are on the way. Will look into getting a UPS for that area as a buffer to future problems.
With regard to the UPS, I should have mentioned that it would be preferable to get one that produces a true sine wave and tightly maintains voltage for the electrical output. AC typically has a symmetrical looping appearance above the midpoint on an oscilloscope and this is what electronics want as their feed voltage. There are cheaper UPS's that have what is called a pseudo-sine wave. What they do is clip the tops of the loops making them square. Longer term -- or if you have susceptible electronics, this will cause problems. A few dollars more for a good sine wave UPS will be cheaper in the long run.

If my attempt to explain sine waves is lacking, have a look here https://en.wikipedia.org/wiki/Alternating_current

Re: Cat6a blowing modems?

Posted: Sat Mar 16, 2019 1:12 pm
by qbit
I would like to point out that you may inform yourself how in your case a good electrical equipotential bonding for additional security of the network hardware can be installed.
And of course correct distances between network lines and power lines etc.etc.

Re: Cat6a blowing modems?

Posted: Sat Mar 16, 2019 2:29 pm
by cliffcoggin
I read a few weeks ago that some USB cables have two of their connections crossed for specific applications. Unfortunately I don't recall the details nor can I find the reference. If you have bought the wrong ones that may explain your problem.

Re: Cat6a blowing modems?

Posted: Sun Mar 17, 2019 2:47 pm
by BG405
cliffcoggin wrote:
Sat Mar 16, 2019 2:29 pm
I read a few weeks ago that some USB cables have two of their connections crossed for specific applications.
First I've heard of this, although some USB leads are power only (i.e. 2-wire instead of 4). Cat5, 6 etc.cables can be crossover (for direct PC-PC connection etc. & ought to be marked as such) but this shouldn't harm anything; modern NICs and modems/routers usually don't care whether it's a straight or crossover cable anyway.

Example: My old NetGear hub has a switch on the uplink port which, when toggled, results in the network LEDs going off briefly, coming back on when the device at the other end (a Linksys router with Tomato firmware in this case) detects it and flips its own switch.

Re: Cat6a blowing modems?

Posted: Mon Mar 18, 2019 7:51 am
by cliffcoggin
BG405 wrote:
Sun Mar 17, 2019 2:47 pm
cliffcoggin wrote:
Sat Mar 16, 2019 2:29 pm
I read a few weeks ago that some USB cables have two of their connections crossed for specific applications.
First I've heard of this, although some USB leads are power only (i.e. 2-wire instead of 4). Cat5, 6 etc.cables can be crossover (for direct PC-PC connection etc. & ought to be marked as such) but this shouldn't harm anything; modern NICs and modems/routers usually don't care whether it's a straight or crossover cable anyway.

Example: My old NetGear hub has a switch on the uplink port which, when toggled, results in the network LEDs going off briefly, coming back on when the device at the other end (a Linksys router with Tomato firmware in this case) detects it and flips its own switch.
Your mention of crossover rings a bell and is what I must have been thinking of. I came across the idea while researching a faulty USB cable of my own, though in my case it was intermittent data transmission. A new cable from a different supplier solved my problem.