Old GEM no longer visible on network

[gregable]

I have an old GEM from 2013. Ethernet only. Black boards with red wiznet serial to ethernet adapter.

It worked in the past, but has been out of operation for a few years due to a bad ethernet cable among other issues. I've replaced the ethernet cable, but I can't get the GEM to connect to the network. I know the new ethernet cable is good, because I've connected other devices to it without problems. LEDs light up on the GEM and switch's matching ports. If I look at my DHCP leases in the router, the GEM does not appear.

I saw the notification about bad power supplies before 2015 and mine was one of them. I've replaced it with another power supply I had laying around, though that's only 1A, so it's possibly still the problem. I ordered another 5V 2A power supply from digikey which I'll try in a week or so when it arrives.

Another thing I have tried was removing the CR2032 battery (which was tricky to accomplish), leave the unit unplugged for 5 minutes, and then plug back in. Didn't help. It's possible the battery is dead, though I'm assuming this couldn't be the issue if the GEM is currently powered by the PSU.

One theory I have is that my network has changed since it was last working and the GEM is not trying to pick up a new lease. Previously the GEM would have had an 192.168.1.X or 192.168.2.X IP, but the network is now configured to assign leases on the 10.0.1.X range. I've scanned 192.168.1.X and 192.168.2.X with NMAP though and found nothing replying.

Any ideas on things to try to bring this back to life?

If it's dead, what options might I have? Would it be reasonable to imagine replacing the wiznet board would work? It appears soldered on, so this might be tricky.

Could I replace this with a newer GEM with WiFi? Would I be able to reuse the old CT clamps?

[ben]

I have an old GEM from 2013. Ethernet only. Black boards with red wiznet serial to ethernet adapter.

It worked in the past, but has been out of operation for a few years due to a bad ethernet cable among other issues. I've replaced the ethernet cable, but I can't get the GEM to connect to the network. I know the new ethernet cable is good, because I've connected other devices to it without problems. LEDs light up on the GEM and switch's matching ports. If I look at my DHCP leases in the router, the GEM does not appear.

I saw the notification about bad power supplies before 2015 and mine was one of them. I've replaced it with another power supply I had laying around, though that's only 1A, so it's possibly still the problem. I ordered another 5V 2A power supply from digikey which I'll try in a week or so when it arrives.

Another thing I have tried was removing the CR2032 battery (which was tricky to accomplish), leave the unit unplugged for 5 minutes, and then plug back in. Didn't help. It's possible the battery is dead, though I'm assuming this couldn't be the issue if the GEM is currently powered by the PSU.

One theory I have is that my network has changed since it was last working and the GEM is not trying to pick up a new lease. Previously the GEM would have had an 192.168.1.X or 192.168.2.X IP, but the network is now configured to assign leases on the 10.0.1.X range. I've scanned 192.168.1.X and 192.168.2.X with NMAP though and found nothing replying.

Any ideas on things to try to bring this back to life?

If it's dead, what options might I have? Would it be reasonable to imagine replacing the wiznet board would work? It appears soldered on, so this might be tricky.

Could I replace this with a newer GEM with WiFi? Would I be able to reuse the old CT clamps?

Do you have a Windows PC available? If so download the GEM Network Utility from https://www.brultech.com/software and try a scan with that. If it's available on the network you should be able to pick it up.

[gregable]

Thanks Ben. I did try the GEM Network Utility and it didn't find anything. It seems pretty likely that the device is not able to set up on the network.

With the battery and power removed, does it make sense that it could still be holding on to the old static IP reservation instead of negotiating DHCP?

[ben]

Thanks Ben. I did try the GEM Network Utility and it didn't find anything. It seems pretty likely that the device is not able to set up on the network.

With the battery and power removed, does it make sense that it could still be holding on to the old static IP reservation instead of negotiating DHCP?

The ethernet-only would hold it yeah but you should be able to change the settings via the GEM Network Utility (it communicates over UDP).

Is there any activity on the LEDs of the Ethernet jack?

[gregable]

Yes, the ethernet lights blink on both the Wiznet device and the switch it's plugged into on the other end. If it's capable of holding the static assignment even on full power loss, maybe I can try setting up a 192.168 network temporarily to connect to it.

[ben]

Yes, the ethernet lights blink on both the Wiznet device and the switch it's plugged into on the other end. If it's capable of holding the static assignment even on full power loss, maybe I can try setting up a 192.168 network temporarily to connect to it.

On your Windows PC, make sure you're using the "Run as Administrator" option with the GEM Network Utility. Also make sure you don't have any active firewall software that could be blocking the UDP send/receives.

[gregable]

I ran GEM Net Utility on Windows as Administrator. Search found nothing. I also ran `arp -a` and did see devices I expected, and none that I didn't recognize.

I don't think there is any firewall on the local network side blocking UDP or anything else, but I'm not sure how to prove/test that claim. I disabled Windows defender, and there is no other firewall-like software that I recall installing.

As one more test, I connected the GEM and the Windows PC via an unmanaged switch. Just two ethernet devices and a switch, nothing else on the network. Still couldn't find the GEM with the utility or `arp -a`.

[ben]

I ran GEM Net Utility on Windows as Administrator. Search found nothing. I also ran `arp -a` and did see devices I expected, and none that I didn't recognize.

I don't think there is any firewall on the local network side blocking UDP or anything else, but I'm not sure how to prove/test that claim. I disabled Windows defender, and there is no other firewall-like software that I recall installing.

As one more test, I connected the GEM and the Windows PC via an unmanaged switch. Just two ethernet devices and a switch, nothing else on the network. Still couldn't find the GEM with the utility or `arp -a`.

Yeah, on the unmanaged switch by itself as long as you programmed in a static IP onto your PC the UDP call should have made it thru.

The GEM has 2 ports right beside the Ethernet module that expose RS232 (Tx, Rx, GND). You can hook up any Serial-to-Ethernet/WiFi/etc. module to those headers.

Do you have anything around you could plug in there and try pulling settings from the GEM?