Marantz SR5012 Not Connecting to LAN but Wifi Works

[mmartell]

The four comm lines are all shorted together. At first I thought maybe the common mode chokes had shorted and that would be a coincidence in itself maybe but to have Tx shorted to Rx makes me think it's not the chokes at all.

The continuity tests were done with the lan/wifi daughtercard removed from the circuit and the Tx+/Tx-/Rx+/Rx- lines appear to run direct from the RJ45 connector (through the chokes) to the daughterboard connector. The schematic (included below) indicates the same thing.

The RJ45 pins are not bent or smashed up.

Is there something peculiar about these RJ45 connectors that something could be going on inside it ?

[R_J]

Re: Marantz SR5012 Not Connecting to LAN but Wifi Works

Some rj45's have internal transformers

[mmartell]

Re: Marantz SR5012 Not Connecting to LAN but Wifi Works

I'm trying to find a part number for it but no luck so far...

[R_J]

Re: Marantz SR5012 Not Connecting to LAN but Wifi Works

Whats the number on it, there are also part numbers in the service manual, it seems to be a a variation of the 99 series
like a HBJ-4109NL
Are you sure its bad?
The lan8720a ic has led status outputs, you could connect a led via 270Ω to ground (led anode to ic pin 3 led1) and check if you get activity when connecting the lan cable

[mmartell]

Re: Marantz SR5012 Not Connecting to LAN but Wifi Works

No I'm not sure what's bad but all four comm lines and pin 4 are shorted to each other.

This is WITHOUT the lan ic connected so I can't imagine what else it could be ?

[mmartell]

Re: Marantz SR5012 Not Connecting to LAN but Wifi Works

In the first pic you can see the lan/wifi module removed from it's connectors on the board.

The second pic shows the TX and Rx lines terminating at the module connector.

Pic three shows the RJ45 and the two common mode chokes. As far as I can tell these comm lines run uninterrupted from the chokes to the module connector.

[R_J]

Re: Marantz SR5012 Not Connecting to LAN but Wifi Works

The maker is DGKYD, KRJ-015XXNL is the pt# I checked there site but can't find the exact number.
It is likely the internal magnetics are what you are reading as shorted

No I'm not sure what's bad but all four comm lines and pin 4 are shorted to each other.

This is WITHOUT the lan ic connected so I can't imagine what else it could be ?

what side of the jack are you measuring the short, on the board or where the ethernet cable plugs in?

[mmartell]

Re: Marantz SR5012 Not Connecting to LAN but Wifi Works

That looks like a "4" in the part number but it's a 1. I still couldn't find it either though.

I'm measuring the short on both sides. Those lines run essentially from the RJ45 socket pin straight through the choke to the edge connector for the module so a short anywhere would register at any point.

[mmartell]

Re: Marantz SR5012 Not Connecting to LAN but Wifi Works

Even if the coating failed on BOTH of these chokes they still shouldn't be shorted to EACH OTHER. That only leaves the RJ45 port as far as I can tell but I still can't imagine the fault inside it...

[R_J]

Re: Marantz SR5012 Not Connecting to LAN but Wifi Works

I did find the jack, it is not just a straight through jack
http://www.rj45transformer.com/sale-...thout-led.html

[mmartell]

Re: Marantz SR5012 Not Connecting to LAN but Wifi Works

Was about to say UH OH. I think I was working under a false assumption the whole time.

I remembered I have the SR5008 right beside it and measured the same damn shorts on it!

So I see you've posted before me and explained why...

So this is not the fault I'm looking at and more likely a fault on the module I guess ?

[mmartell]

Re: Marantz SR5012 Not Connecting to LAN but Wifi Works

R J,

First, please don't stop entertaining my lunatic rants in this sub-forum.

Secondly after looking over the module and seeing nothing wrong I reassembled the module and tried running the unit to see if there were any leds on it that might point out a diagnostic clue...

But now it seems to work.

I know I've had this apart before but the module must not have been seated properly ?

Thanks again.

Nothing to see here folks, move along. Lol.

[R_J]

Re: Marantz SR5012 Not Connecting to LAN but Wifi Works

I have see those surface mount plugs with poor solder connections on other units.

The ic I refered to in post#4 was on the SR5008 which does'nt use a module.