Random ports not working on server switch - is it a fire hazard?

[Filingo]

The manager at my workplace let me pick up some stuff he wanted to throw so one of the things I took was a Dell PowerConnect 2716 switch

 

I only used it so far with 3 ports and everything was working. But now I wanted to add another one cable and noticed it doesn't work. Then I checked all the other ports and some of them don't work as well.

Is it a sign of a problem that could cause a fire? Maybe loose wires that can cause shortcuts?

Ty

[RollyShed]

3 minutes ago, Filingo said:

The manager at my workplace let me pick up some stuff he wanted to throw so one of the things I took was a Dell PowerConnect 2716 switch

 

I only used it so far with 3 ports and everything was working. But now I wanted to add another one cable and noticed it doesn't work. Then I checked all the other ports and some of them don't work as well.

Is it a sign of a problem that could cause a fire? Maybe loose wires that can cause shortcuts?

Ty

How is it going to start a fire?

 

It is a 16 port switch, you have plenty of choices as far as sockets to try if it is bad connection.

What is supplying the signal source?

What are you connecting to, what computers?

Where did your cables come from and are they good?

[Filingo]

27 minutes ago, RollyShed said:

How is it going to start a fire?

 

It is a 16 port switch, you have plenty of choices as far as sockets to try if it is bad connection.

What is supplying the signal source?

What are you connecting to, what computers?

Where did your cables come from and are they good?

thanks!

The Ethernet cables are the ones I've been using for a long time, they're good

The power source cable is a C13 cable, 220V, so the switch has its own PSU

 

connecting to 2 computers - 1 cable comes from the router and 2 going out to the computers

 

The signal is pretty good on the ports that do work.

 

I mean the fact that it's was destined to be thrown away and that few ports don't work I was thinking maybe some internal electrical issue but I guess Dell should be pretty safe to prevent such thing right?

 

Just a bit paranoid after recent stories in news about people burning from phone chargers or electrical bicycle batteries

[mariushm]

First you should figure out if those ports are actually faulty or just disabled / configured so they won't work by default - they could be configured in a VLAN or in some mode  that will reject your network card. 

Seems the switch should have some web management - see if you can access the management interface and go from there. 

See manual at page 33 where it explains how to start management interface :  https://dl.dell.com/manuals/all-products/esuprt_ser_stor_net/esuprt_powerconnect/powerconnect-2716_user's guide_en-us.pdf

 

The device is delivered in Unmanaged Mode. The device must be changed to Managed Mode
before it can be configured. To change to Managed Mode, the device must be fully operational in
Unmanaged Mode (Managed Mode LED has stopped blinking and is off). Once the Managed
Mode LED has stopped blinking, press the Managed Mode button. The switch reboots and the
Managed Mode LED blinks for approximately 90 seconds and stays lit. When the Managed Mode
LED stays lit, the switch is ready to be configured. The default IP address is 192.168.2.1, the
default User Name is 'admin', and the default password is left blank.

 

So try adding a second Ip to your network card, ex 192.168.2.2 - to be in same 192.168.2.* range - and subnet mask 255.255.255.0  and connect the ethernet cable between your computer and the switch , then enter 192.168.2.1 in your browser to see if it works.

 

Otherwise, no, faulty ports can be for various reasons. 

Visually inspect the ports and make sure the 8 contacts inside the port are all aligned and not touching / shorting, and make sure they're flexible

I'd also suggest cleaning the contacts, making sure there's no oxides or dirt in the contacts/

 

There's a transformer behind every port, to provide isolation, sometimes this tiny isolation transformer is hidden inside the ethernet port, but in a switch it's normally 2 or 4 or more  transformers in a single package -  port not working could also be if one of these transformers is faulty (maybe due to a power surge on the port, the coil of wire in the transformer broke protecting the internals of the switch like a fuse, so now the transformer no longer works.  if this is the case, you could potentially fix the ports by replacing that isolation transformer with a new one.

 

Found a video where you can see the insides of dell 2716 ... see below at 1:20 , the black rectangles with LF and G4P109 written on them are the isolation transformers (one rectangle for 4 ethernet ports) 

G4P109 is the product code, here's datasheet: http://www.bothhandusa.com/datasheets/filter-transformer/1000-quad-dip/G4P109-I-LF-RevA1-071004.pdf

They cost around $14 each on eBay, so probably not worth fixing if they're actually faulty, when you can get an unmanaged 16 port switch for 20-30$.

 

 

[Filingo]

6 minutes ago, mariushm said:

First you should figure out if those ports are actually faulty or just disabled / configured so they won't work by default - they could be configured in a VLAN or in some mode  that will reject your network card. 

Seems the switch should have some web management - see if you can access the management interface and go from there. 

See manual at page 33 where it explains how to start management interface :  https://dl.dell.com/manuals/all-products/esuprt_ser_stor_net/esuprt_powerconnect/powerconnect-2716_user's guide_en-us.pdf

 

The device is delivered in Unmanaged Mode. The device must be changed to Managed Mode
before it can be configured. To change to Managed Mode, the device must be fully operational in
Unmanaged Mode (Managed Mode LED has stopped blinking and is off). Once the Managed
Mode LED has stopped blinking, press the Managed Mode button. The switch reboots and the
Managed Mode LED blinks for approximately 90 seconds and stays lit. When the Managed Mode
LED stays lit, the switch is ready to be configured. The default IP address is 192.168.2.1, the
default User Name is 'admin', and the default password is left blank.

 

Otherwise, no, faulty ports can be for various reasons. 

Visually inspect the ports and make sure the 8 contacts inside the port are all aligned and not touching / shorting, and make sure they're flexible

I'd also suggest cleaning the contacts, making sure there's no oxides or dirt in the contacts/

 

There's a transformer behind every port, to provide isolation, sometimes this tiny isolation transformer is hidden inside the ethernet port, but in a switch it's normally 2 or 4 or more  transformers in a single package -  port not working could also be if one of these transformers is faulty (maybe due to a power surge on the port, the coil of wire in the transformer broke protecting the internals of the switch like a fuse, so now the transformer no longer works.  if this is the case, you could potentially fix the ports by replacing that isolation transformer with a new one.

 

Found a video where you can see the insides of dell 2716 ... see below at 1:20 , the black rectangles with LF and G4P109 written on them are the isolation transformers (one rectangle for 4 ethernet ports) 

G4P109 is the product code, here's datasheet: http://www.bothhandusa.com/datasheets/filter-transformer/1000-quad-dip/G4P109-I-LF-RevA1-071004.pdf

They cost around $14 each on eBay, so probably not worth fixing if they're actually faulty, when you can get an unmanaged 16 port switch for 20-30$.

 

 

Nice find!!! 

Indeed it was in Managed mode, however even when I turned it off these ports still don't work.

 

I mean, it could be worth it to buy for $14 if you want a Managed switch and you know how to solder.

I know I don't solder well so I better not try to fix it.

 

But if it's safe to use it with broken ports I'd just keep using it, I don't need all these ports anyway

 

 

[mariushm]

Well, the way I understand it,  managed mode means that management is turned on in order to access the management interface and configure things. Then once settings are saved, it flips back to "unmanaged" but those settings remain active only you can no longer access the management interface. 

So go in management mode, access interface, see if some ports are disabled or not, if they're part of a different vlan or not, maybe there's a list of ports and their state somewhere so you could plug another cable between a device and a port and refresh that list to see if the switch detects the device at the end of the cable (and repeat with every port except the one you're currently using for management)

 

So the button is not a switch between unmanaged (dumb) and managed , it's just a "i want to be able to access management interface" button.

read that user guide I linked to, to make sure they way I understand it is correct. 

 

otherwise yeah, you can use it, and there's very low chance of something going in flames ... but even if something does, it's a metal box..

[Filingo]

19 minutes ago, mariushm said:

Well, the way I understand it,  managed mode means that management is turned on in order to access the management interface and configure things. Then once settings are saved, it flips back to "unmanaged" but those settings remain active only you can no longer access the management interface. 

So go in management mode, access interface, see if some ports are disabled or not, if they're part of a different vlan or not, maybe there's a list of ports and their state somewhere so you could plug another cable between a device and a port and refresh that list to see if the switch detects the device at the end of the cable (and repeat with every port except the one you're currently using for management)

 

So the button is not a switch between unmanaged (dumb) and managed , it's just a "i want to be able to access management interface" button.

read that user guide I linked to, to make sure they way I understand it is correct. 

 

otherwise yeah, you can use it, and there's very low chance of something going in flames ... but even if something does, it's a metal box..

It's so weird, I can't get into the web interface.

I unplugged any cables from the switch, then plugged directly between the PC and the switch and still can't get to 192.168.2.1: "This site can’t be reached"

 

I tried to hold the Managed Mode button for 30 seconds to reset it to defaults, still can't connect

 

 

[mariushm]

You also need to configure your network card to have an IP within the same range.  

Your network card is probably configured to automatically receive IP from the router's built-in dhcp server but when you connect the cable directly to the switch, there's no such dhcp server to give your network card an IP address. 

That's why I said that you should manually add an IP address from the same range to your card's configuration . As the manual says, IP should be 192.168.2.1 , try  setting your card 192.168.2.2  or 192.168.2.100 (or anything but .1 at the end) and subnet mask 255.255.255.0 should be fine.

 

You'll have to check the manual to see if it's possible to have this default IP changed, maybe they changed the default IP.  In that case, maybe open the switch and see if there's some jumper to reset the switch to defaults, or some internal button you could hold down for a few seconds to reset everything to defaults. The video I linked to isn't clear enough to see such things.  Check the manual, though it may not say it, as they wouldn't advertise "hey, open the switch and void warranty to reset the settings"

 

Also follow the instructions .. wait until the led stops blinking, then press the button and the switch should reboot, then you should wait up to around 90s until the led stops blinking and led remains on .. then try to access it. 

 

btw. there's also a firmware update for 2716 here : https://www.dell.com/support/home/en-us/drivers/driversdetails?driverid=r112903&oscode=naa&productcode=powerconnect-2716

Should be able to update the firmware from the web interface, or through TFTP (you'll need separate tftp server program to do it if that's the case, but there's free tftp servers available)

 

[Filingo]

36 minutes ago, mariushm said:

You also need to configure your network card to have an IP within the same range.  

Your network card is probably configured to automatically receive IP from the router's built-in dhcp server but when you connect the cable directly to the switch, there's no such dhcp server to give your network card an IP address. 

That's why I said that you should manually add an IP address from the same range to your card's configuration . As the manual says, IP should be 192.168.2.1 , try  setting your card 192.168.2.2  or 192.168.2.100 (or anything but .1 at the end) and subnet mask 255.255.255.0 should be fine.

 

You'll have to check the manual to see if it's possible to have this default IP changed, maybe they changed the default IP.  In that case, maybe open the switch and see if there's some jumper to reset the switch to defaults, or some internal button you could hold down for a few seconds to reset everything to defaults. The video I linked to isn't clear enough to see such things.  Check the manual, though it may not say it, as they wouldn't advertise "hey, open the switch and void warranty to reset the settings"

 

Also follow the instructions .. wait until the led stops blinking, then press the button and the switch should reboot, then you should wait up to around 90s until the led stops blinking and led remains on .. then try to access it. 

 

btw. there's also a firmware update for 2716 here : https://www.dell.com/support/home/en-us/drivers/driversdetails?driverid=r112903&oscode=naa&productcode=powerconnect-2716

Should be able to update the firmware from the web interface, or through TFTP (you'll need separate tftp server program to do it if that's the case, but there's free tftp servers available)

 

I set a static ip of 192.168.2.100 with gateway 192.168.2.1 but still when I connect the switch it won't get to 192.168.2.1. I will try to reset it again and then open it if nothing works (subnet 255.255.255.0)

 

Update: Forgot to put it back to Managed mode

 

Now it works, thanks!

It even has a built-in cable test, and the ports are just dead

 

I noticed it's 4 ports dead in square shape: ports 9, 10, 11, 12

so maybe there's one of these G4P109 behind these 4 that's burnt?

[mariushm]

Well, if you have a good soldering station / iron , you could desolder two and flip them and see if the other group of four ports fails. Then you'll know it's the transformer the problem. 

otherwise, it could be some custom Ic under those heatsinks that's failed in which case let it go, not worth the hassle. 

 

You could just use it as a 12 port switch though.

[Filingo]

3 hours ago, mariushm said:

Well, if you have a good soldering station / iron , you could desolder two and flip them and see if the other group of four ports fails. Then you'll know it's the transformer the problem. 

otherwise, it could be some custom Ic under those heatsinks that's failed in which case let it go, not worth the hassle. 

 

You could just use it as a 12 port switch though.

haha 12 is more than enough for me, I only use 3 xD

 

 

[RollyShed]

On 8/18/2022 at 8:40 PM, Filingo said:

Just a bit paranoid after recent stories in news about people burning from phone chargers or electrical bicycle batteries

They are completely different from a modem/router. Those items handle POWER. The modem handles low voltage signals, micro-watts of power.