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npeca75
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crs309-1g-8s+pc ETH problem

Sat Mar 04, 2023 9:03 am

Hi to all

unfortunately, my crs309 got a spike from CATV modem and standalone ETH port is burn out

it is showing link present even without attached cable

i like to ask, is there anyone who tried to service this/similar problem ?

soldering is not a problem,
but for now, i try to find any schematic or another person who tried something similar, only to avoid unnecessary soldering and stripping parts off

question is, is there any protective diodes or similar stuff for protecting CPU pins which are connected to ETH port ?
maybe they are faulty

BR Peca
 
cdemers
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Re: crs309-1g-8s+pc ETH problem

Sun Mar 05, 2023 5:13 am

I don't happen to have this model, so will go with how I usually repair this type of problem. Check all the passive components next to the jack, make sure none have shorted. (Shorted capacitors will act more like a wire, resistors often go open circuit.) The large black component behind the port is an isolation transformer (pc13n1zh), it's possible it's been damaged by the surge (it's not meant to handle large amounts of current from that kind of surge). Then there's the POE circuitry next to that, there's a fuse, rectifier, not sure what the other device is I can't find a part number on the photos i found online, but probably part of the poe for extracting the power and letting the signal to continue though to the isolation transformer, that could be damaged (but less likely as it's more of a power circuit). I'm just going by a picture I found online of the board layout, and the manufacturer spec sheets of the parts. I would start with all the passive components and do process of elimination, and trace out the circuit, if they all test fine I would probably lean more towards the isolation transformer has faulted as it's not supposed to carry a lot of current. Now if it's really bad it may have also damaged the two chips next the isolation transformer (D1, D2), which lead to the SOC, which if it made it past that and damaged the SOC then there's nothing you can do to fix it.
 
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npeca75
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Re: crs309-1g-8s+pc ETH problem

Mon Mar 06, 2023 10:13 am

hi @cdemers

after desoldering transformer to get a clear measuring without transformer coils interference, sadly i realized that passive components are OK
furthermore, even without transformer, MT reporting link UP
so, next step is AR8033 al1a PHY
 
kidalabama
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Re: crs309-1g-8s+pc ETH problem

Fri May 05, 2023 1:59 pm

https://www.youtube.com/watch?v=7E4f5lGVNvY
NS602462 vs pc13n1zh. Is it same ?

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