Author Topic: Continuous Router Failure  (Read 1686 times)

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Offline Monkeh

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Re: Continuous Router Failure
« Reply #25 on: October 08, 2019, 04:06:41 pm »
Do you have the part number for those capacitors? What is the voltage rating on them?

They're unmarked ceramic caps, why would you expect him to have part numbers?

And please, explain the compensation circuit managing to explode in the first picture he posted.. (I'll give you a hint: it involved a screwdriver or a knife)
 

Offline EEEnthusiast

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Re: Continuous Router Failure
« Reply #26 on: October 08, 2019, 04:11:18 pm »
Why would anyone sabotage a router? Unless he wants our friend to go out of business.
Well the recent pictures show the caps being blackened. This is surely due to over voltage or mechanical stress causing the cap to short. The recent photo (2nd one) does not show any mechanical damage to the part.
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Offline wraper

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Re: Continuous Router Failure
« Reply #27 on: October 08, 2019, 05:32:51 pm »
Why would anyone sabotage a router? Unless he wants our friend to go out of business.
World is full with idiots, vandals, maniacs and all sorts of weirdoes. When people poison neighbors dog and do other stupid shit, why would not someone decide to do this with routers?
Quote
Well the recent pictures show the caps being blackened. This is surely due to over voltage or mechanical stress causing the cap to short.
MLCC don't fail like that. One cap simply has top corner charred. That cap is not even broken with 99% probability. Someone just short circuited it's terminal. Second capacitor corner charred/ melted and crack coming from that. The same thing, just with added mechanical force. You would have whole board covered with burnt semiconductors and traces before ceramic capacitors will start exploding due to overvoltage.
 

Offline bdunham7

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Re: Continuous Router Failure
« Reply #28 on: October 08, 2019, 07:04:37 pm »
After a couple more failed devices we have been able to match the time stamps of the failures to the workshop next door turning off their compressor (medium sizes wood working shop).

Electricians have installed surge protection on the incoming lines but they are not helping (not sure of the spec or quality). Have also lost faith in their abilities. What are the tricks to surge protection for sensitive electronics?

If you actually have a valid, properly functioning UPS in true online mode (double conversion) there is no possibility of surges reaching your equipment via any mode other than ground.  Please read my previous message about what to do about that...
 

Online MagicSmoker

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Re: Continuous Router Failure
« Reply #29 on: October 08, 2019, 07:17:26 pm »
Second capacitor corner charred/ melted and crack coming from that. The same thing, just with added mechanical force. You would have whole board covered with burnt semiconductors and traces before ceramic capacitors will start exploding due to overvoltage.

Hmm, yes, it definitely looks like "mechanically induced failure" to me, too. Note to OP: a line reactor won't protect against that; neither will a double-conversion UPS.

 

Offline Mr.B

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Re: Continuous Router Failure
« Reply #30 on: October 08, 2019, 08:44:19 pm »
To the OP.
What @wraper said...
Install tamper proof seals and a hidden webcam.
The cause of your continuous failures will be revealed fairly quickly.
Time is the overseer of all things.
 

Offline EEEnthusiast

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Re: Continuous Router Failure
« Reply #31 on: October 09, 2019, 03:04:01 am »
To the OP.
What @wraper said...
Install tamper proof seals and a hidden webcam.
The cause of your continuous failures will be revealed fairly quickly.
And keep your rifle loaded.
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Offline drussell

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Re: Continuous Router Failure
« Reply #32 on: October 09, 2019, 04:01:16 am »
I agree that a video camera is the likely solution to your router woes.  :)

That is mechanical damage. 

That is not the way components blow themselves off the board.
 

Offline NiHaoMike

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Re: Continuous Router Failure
« Reply #33 on: October 10, 2019, 03:09:31 am »
Perhaps replace the stock PSU with a cheap metal box PSU of the type commonly found on 3D printers, then mount it over the router. With luck, if it is indeed someone intentionally damaging stuff, adding mains power would greatly increase the chance they get more of a surprise than they were expecting.
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Offline Berni

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Re: Continuous Router Failure
« Reply #34 on: October 10, 2019, 05:18:35 am »
Yeah a lot of this again looks like someone poked a screwdriver in there.

Id just install a hidden webcam and nothing else so that anyone who is doing this does not notice any counter measures and shows himself. Once you have video evidence show that to your costumer and ask them to fix this or you won't be fixing there routers anymore.
 

Offline nuclearcat

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Re: Continuous Router Failure
« Reply #35 on: October 10, 2019, 11:51:12 am »
Yeah a lot of this again looks like someone poked a screwdriver in there.

Id just install a hidden webcam and nothing else so that anyone who is doing this does not notice any counter measures and shows himself. Once you have video evidence show that to your costumer and ask them to fix this or you won't be fixing there routers anymore.
Hidden survelliance might violate country laws.
Intrusion detection is ok, camera inside box is ok, but hidden cam most likely will put in big trouble.
 

Offline drussell

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Re: Continuous Router Failure
« Reply #36 on: October 10, 2019, 02:17:55 pm »
Hidden survelliance might violate country laws.Intrusion detection is ok, camera inside box is ok, but hidden cam most likely will put in big trouble.

I'm pretty sure that in South Africa, as long as you have your sign at the door that says something like "these premises are monitored by video surveillance," you're fine and will even be able to legally use your recordings to prosecute someone if it comes to that, whether the cameras are "hidden" or in obvious plain sight.  (As long as you don't put them in washrooms, changing rooms, etc.)

"Fairly warned, be thee, says I...."  :)
 

Offline DuncanCT

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Re: Continuous Router Failure
« Reply #37 on: October 10, 2019, 02:19:38 pm »
Latest picture of the surge protection device installed on the DB.

Best theory at the moment is there is a second PC that is not behind a decent UPS and it's passing whatever is incoming via the land cable connecting it to the router. I'm going to install a wireless link and remove the lan cable next.

The only other "exposed" connection would be the copper line for the (A)DSL connection. Assume if a PC can pass this through a lan cable then so can a POTS line via can a modem?
« Last Edit: October 10, 2019, 02:29:41 pm by DuncanCT »
 

Offline drussell

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Re: Continuous Router Failure
« Reply #38 on: October 10, 2019, 02:30:35 pm »
One additional snippet...

Many years ago at my Dad's office downtown, packages of microwave popcorn kept disappearing from the kitchenette area.  We would buy those big flats of like 48 packages from Costco for anyone in the office who wanted a snack to be able to toss one in the microwave.  But they were disappearing at night. 

Now, my dad used to be quite the night owl and would often return to the office at 8-9 PM after and after-dinner-nap and work until the wee hours of the morning before returning home.  Some nights he could smell that popcorn had been recently popped.  It's pretty obvious.

Now, the only people that would have been in our office in the evening would be the (high-rise downtown office) building's cleaning staff who came in each night to vacuum, empty the garbages, paper recycling, etc. so he spoke to the building management who were rightly concerned.  It wasn't that items of significant value were disappearing, but the principle of the thing.

Management's solution was to cut a fairly obvious, crude cutout in an old monitor cardboard box that was up on a top shelf in that room and place a video camera in there.  Sure enough, one of the cleaning staff was helping themselves to a package of popcorn, from inside one of the cabinets.  They were let go from their employment for snooping through cupboards and helping themselves to packages of popcorn.  Who knows how many desk drawers and office nooks and crannies they had been peering into and what else they felt they might have been able to abscond with.

It was very effective.  I believe the video camera was only there for one night.
 

Offline drussell

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Re: Continuous Router Failure
« Reply #39 on: October 10, 2019, 02:34:38 pm »
Latest picture of the surge protection device installed on the DB.

That surge suppressor looks like it might be feeling a tad ill...   :-DD

I still think your power input issues are a red herring.  You are likely chasing two different issues.

Those photos you showed of the router damage is not damage that would be caused by mains-induced surges or spikes.  It simply is not what surge damage at any energy level looks like, from mild spike to lightning strike.
 

Offline Berni

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Re: Continuous Router Failure
« Reply #40 on: October 10, 2019, 03:23:39 pm »
Yep something that could cause a surge protector to turn to charcoal like that would likely also leave its mark on the routers mains power supply.

Nothing wrong with video surveillance as long as you put up a sign on the door or something, tho to be fair unless its a big sign most people won't even notice it due to these signs being all over the place so you sort of start ignoring them. But if anyone objects to being unlawfully filmed then you can still point at the sign on the door. But even if whoever is doing this notices the sign and stops, that's also a win situation since your routers are no longer being destroyed.
 

Offline duak

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Re: Continuous Router Failure
« Reply #41 on: October 11, 2019, 03:58:21 am »
What do these capacitors do?  Do they connect an input jack terminal to chassis or safety ground/earth?  If so, maybe there is a damaged cable or improperly connected neutral or safety ground/earth connection somewhere, eg. conduit connector not tightened.  This allows common mode transient currents to return through a path that is not robust enough to handle it.

I remember a junior engineer added some transorbs between system common and chassis on his board to divert transients.  During system transient susceptibility testing, the transorbs were blown off the boards, unfortunately not cleanly.

 

Online Jeroen3

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Re: Continuous Router Failure
« Reply #42 on: October 11, 2019, 05:59:57 am »
You should install a power quality monitor, after that you can move the invoice for component replacement to the grid company.
Eg: PQube or mobile Fluke/Yokogawa.
 

Offline nuclearcat

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Re: Continuous Router Failure
« Reply #43 on: October 12, 2019, 04:01:18 am »
Latest picture of the surge protection device installed on the DB.

Best theory at the moment is there is a second PC that is not behind a decent UPS and it's passing whatever is incoming via the land cable connecting it to the router. I'm going to install a wireless link and remove the lan cable next.

The only other "exposed" connection would be the copper line for the (A)DSL connection. Assume if a PC can pass this through a lan cable then so can a POTS line via can a modem?
Has this PC (or network card) or ADSL modem ever burned down by surge? Usually, when such a surge passes through the equipment, something else than mikrotik may burn out. (unless it passed by shields/ground and pc/dsl modem doesn't have ground/ or they was disconnected from mains).
For example in last incident lightening entered server room over asterisk connected to POTS, from card to "ground" of PC, and because it was not properly grounded, passed over whole rack to device that was has connection to ground, burning everything on the way. After i traced, i found biggest damage on Asterisk FXO port. You can see traces of explosion on card under module 3, and exploded MOV(not sure, lazy to check if it is MOV) on removed module, it was not visible, until i removed it.
852946-0

Was there a thunderstorm when Mikrotik failed? (Most likely yes, just noticed surge arrester charred)

And yes, POTS quite common source of surges, unless they are completely underground all the way and no underground high voltage lines nearby. If it is not underground, you definitely need to put surge protector on POTS, they should not be expensive.
Otherwise surge will come over POTS, pass your DSL modem and then, or over DSL modem supply to ground, or more likely over network to closest device that is connected to ground.

P.S. Also avoid shielded cables and plugs.They work only when properly grounded, and when not - they do exactly opposite.
 


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