Dead Ethernet Port - Diagnostics Possible?

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Level 1

16 points

Dead Ethernet Port - Diagnostics Possible?

I have a 2-Mac LAN G4 Tower & Cube, and recently lost the ability to communicate from the G4 tower. I've used a hub as a diagnostic device and found that connecting an ethernet cable between a good mac and the hub caused the hub to light up for the port with the connection, but not with the same cable between the G4 tower and the hub. So, I conclude that the G4's ethernet port is dead. As someone on this group has pointed out, that port is attached to the logic port. I'm wondering whether I could check voltages on the port connectors to define the problem further? That is, is there a power supply that's bad, or what?

Posted on Oct 22, 2005 6:40 PM

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Answer 1

Oct 22, 2005 9:20 PM in response to Glenn Haste

Glenn,

If the power supply had gone casters up you'd have more problems thatn a dead Ethernet port.

Here's some stuff to try. Open up System Preferences, Network to monitor the status of the Ethernet port. Post the status.

Swap out the cable.

Try a different port on the router/switch.

Power cycle the router/switch.

Post the results.

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Answer 2

Henry B.

Level 9

78,731 points

Oct 23, 2005 8:42 AM in response to Glenn Haste

The "voltages" on the contacts of an ethernet port are not measurable in any useful way with a simple voltmeter. Your ethernet hub itself is the best "diagnostic tool" available for anyone but a electronics tech - and if the status light for the port your Mac is connected to works fine for other computers but in the case of the problematic Mac shows no light then either (a) the cable is defective or (b) the Mac's ethernet port is defective. Do follow Mike's advice above - but I'm not optimistic.

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Answer 3

Glenn Haste Author

Level 1

16 points

Oct 23, 2005 8:48 AM in response to Glenn Haste

Mike on Maui: What a neat user name! Firt, let me say how much I appreciate your response. I'd love to learn that my troubles are due to bad settings or cables, or something that's easily remedied. I fear that's not the case.
My present situation is that I have a 'good' G4 (466 MHz) to compare with the 'suspect' G4 (400 MHz) with the questionable ethernet port. Each have ethernet cables connected to a router which is then followed by a cable modem for internet access. In addition, I have a left-over hub for diagnostics.

When both are connected to the router: Good one lights up its port light and makes internet connection. Suspect doesn't - with either of two ethernet cables.
When both are connected to the hub: Port light-up is as above.
Look at System Preferences > Network, Location - Automatic, Show built-in Ethernet: Good one has reasonable numbers for IP Address, Subnet Mask, and Router. Suspect has blanks. Each has AppleTalk active, reasonable values fo DHCP Client ID, and Ethernet Address, each is configured using DHCP.
I haven't cycled the power for the router, but I have for the hub. That made no difference.

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Answer 4

Oct 23, 2005 9:40 AM in response to Glenn Haste

Glenn,

Based on the trouble shooting steps you've done it does appear that the Ethernet port is toast. Hopefully a replacement NIC won't cost too much.

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Answer 5

Oct 24, 2005 6:39 AM in response to Glenn Haste

I have a very similar problem with my G4 tower(400mhz). I have tried everything and dicided it was the port was out. I searched and found a NetLINE/Farallon 10/100 Ethernet PCI card on ebay, for like $15.00... there was a toll-free tech number, a business number and a web page on the back of the box... none of which worked. When I tested the card the Mac said it couldn't find the driver. The seller on ebay said they would replace the product but common sense tells me that this won't resolve the problem. My question is... Can anyone share any advice on a safe and reliable product. I'm hoping there is one that is compatible with both OS 9 & X. I've done a bit of research online but I always end up with an unanswered question. Another thing... are there any problems associated with installing an Ethernet card in a computer with a built in port? I hope someone can help.
Sincerely,
ME

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Answer 6

Oct 24, 2005 12:43 PM in response to Jody Stone

The only problem you might have with a PCI NIC is sleep support - if it's a big deal for you, check the forums and you'll find references to cards that are better and worse.
Me, I turn my machine off when I'm not using it...

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Answer 7

Oct 25, 2005 4:51 AM in response to Glenn Haste

The sleep thing isn't a problem for me. I turn mine off too.
My main problem is knowing what card to get... and where to look for it. If anyone knows just a standard Ethernet PCI card for the G4... your input would be greatly appreciated. I'm tired of wasting time buying ones that don't work... and, very tired, of not having a connection on my Mac. Please help.

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Answer 8

Glenn Haste Author

Level 1

16 points

Oct 25, 2005 12:52 PM in response to Glenn Haste

Jody, I hope you get a response since I'm now also in the market for such a card. Your last sentence is very relevant (i.e. problems between the new card and the old port) To be Clintonian, a lot depends on the meaning of dead. My port is clearly dead since it doesn't function for communication. But it may not be dead to the computer, since it still thinks I have a built-in ethernet.

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Answer 9

Glenn Haste Author

Level 1

16 points

Nov 5, 2005 6:49 AM in response to Glenn Haste

Jody: You may have already solved your ethernet port problem, but I'll let you know of my (good) experience. I bought a D-Link NIC ethernet port on E-bay (DFE-530), then downloaded the driver from the D-Link site. I installed the driver in both OS X & OS 9.1 with no problems. I've only used the NIC in OS X but it works well. My profile shows that card, as well as the built-in ethernet. Of course, we know that the later isn't true but I guess the built-in unit is still there logically, even though the port is dead. So, I hope you find a similar solution or maybe you already have.

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