Who can help solve my problem?

scwilson

scwilson

scwilson

Associate
Joined
18 Oct 2010
Posts
193
Location
South Coast UK
This is a real ***** of an issue. Never in my life of computing have I see anything so bizarre.

To set the scene ...

BT HomeHub 3
TP-Link Gigabit Switch
Laptop (Wireless)
HTPC (Ethernet)
Desktop PC (Ethernet)

**HTPC** ====> Can access internet OK
Antec ISK300-150
ASRock E350
Windows 7 64-bit
8GB RAM
60GB SSD

**Laptop** ====> Can access the internet
Dell Precision M6300
2GB RAM
Windows 7 32-bit

**Desktop PC** ====> Can't access internet
Antec 300
Asus Crosshair III
4GB RAM
60GB SSD

So the desktop PC can longer access the internet. It used to when I built it (November 2010) but for the last 3-4 months, I get the yellow exclamation symbol. I've swapped ethernet cables, ethernet cards, re-installed the operating system to no avail. I am currently using an Intel dual port gigabit pro network card but prior to that was using onboard. I swapped to the separate card because I thought the onboard LAN was causing the issue.

I am wondering if my PSU in the desktop PC (Antec TruePower 650) is actually causing interference but I have no way of telling unless I go and buy a new one to test out.

Any ideas what could be causing this? The odd thing is, when my broadband link is around 7MB, then my desktop PC seems to connect just fine but usually now, since they upgraded my local exchange, I am getting 9, 10, 11MB and the my desktop PC displays this yellow exclamation mark all the time so no internet access for me.

Here are the current stats from my router viewed via my laptop (wireless);

ADSL Line Status
Connection information
Line state:
Connected
Connection time:
1 day, 10:49:38
Downstream:
9,955 Kbps
Upstream:
1,050 Kbps
ADSL settings
VPI/VCI:
0/38
Type:
PPPoA
Modulation:
G.992.5 Annex A
Latency type:
Interleaved
Noise margin (Down/Up):
1.4 dB / 4.1 dB
Line attenuation (Down/Up):
40.5 dB / 21.4 dB
Output power (Down/Up):
20.6 dBm / 12.2 dBm
FEC Events (Down/Up):
86939052 / 39850
CRC Events (Down/Up):
107523 / 1423
Loss of Framing (Local/Remote):
0 / 0
Loss of Signal (Local/Remote):
0 / 0
Loss of Power (Local/Remote):
0 / 0
Loss of Link (Remote):
0
HEC Errors (Down/Up):
584923 / 1392
Error Seconds (Local/Remote):
0 / 1341

I am unsure if it is a BT network issue but my HTPC and Laptop can connect ok, it looks to me as if my desktop PC has problems.
 
Last edited:
PSUs are switch mode devices that has regulators that switch from fully on to fully off at 50khz - 1 MHz. It's technically possible that this electrical noise is interfering with your Ethernet signal which also sits within that frequency band. However I've never heard of it.

Open up the connection properties and have a look at the ip that's been assigned by the PC. If its 169.254.xxx.xxx then you have a DHCP issue and setting the ip, subnet and gateway should help.
 
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Thanks. I did an ipconfig /renew and the yellow exclamation mark went away but I still could not browse any websites. Could not ping any sites either yet had a valid DHCP assigned IP address.

I restarted my router 3 or 4 times and it synced at 7.5MB instead of the previous 9.9MB. At which point I could browse the internet. Has anybody ever heard of anything like this?
 
The noise margin at your higher speed is a bit on the low side and could cause instability issues but I can't see why it's not allowing a client to connect to the Internet. I suppose the router has to work harder to see the ADSL signal and is struggling to do that and connect your PC but if this were the case then surely the other devices would also be unconnected.

A strange one.

Are you able to ping and browse the router's web interface in this partially connected state?
 
Tealc said:
The noise margin at your higher speed is a bit on the low side and could cause instability issues but I can't see why it's not allowing a client to connect to the Internet. I suppose the router has to work harder to see the ADSL signal and is struggling to do that and connect your PC but if this were the case then surely the other devices would also be unconnected.

A strange one.

Are you able to ping and browse the router's web interface in this partially connected state?
Click to expand...


Yes I can always get to the hub admin page, i.e, 192.168.1.254. Also, the local networking is fine, it's just the web.
 
Deception said:
Try changing your DNS servers to googles (8.8.8.8 and 4.4.4.4). See if it lets you then.
Click to expand...

OK - I can try this. Presumably just set this in the TCP/IP properties of the network adapter? It's odd that my other pc (HTPC) has no issues at all at these higher ADSL speeds.
 
I keep getting on at my ISP (BT) but realize now that the problem appears to point towards this one PC of mine, which is only a year old. All I know is when the sync speed is around 7.5MB or less, it works perfectly fine.
 
Swap the ports for the Desktop ethernet cable at the switch with the HTPC cable. If the HTPC cannot access the internet, or the Desktop can access the internet then you have a faulty switch. Failing that plug it into the home hub directly.

Best thing you can do in situations like this is eliminate everything along the line. You have done lots at the PC, maybe the hardware itself has a fault in a port?
 
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The order to test..

change the port it's connected to at the router
change the cable
boot from a ubuntu live cd and test the network
(if this works, reset all network related settings in Windows, and update drivers)
change network card
reinstall Windows
drop kick PC down the stairs
 
bledd. said:
The order to test..

change the port it's connected to at the router
change the cable
boot from a ubuntu live cd and test the network
(if this works, reset all network related settings in Windows, and update drivers)
change network card
reinstall Windows
drop kick PC down the stairs
Click to expand...

Thanks :)

I suspect I will end up at the last point on your check list. I tried last night with an Ubuntu Live CD and it could not access the internet also. I've changed the network card and tried a new cable already and re-installed windows so it just leaves me with checking the ports. I might also remove the Gigabit switch completely and try direct 100base with the hub.
 
I changed the motherboard and got a new case anyway as my old case was cack. Still had the same problem. Finally got a BT engineer to come out and see the problem I was having. He phoned up and got them to change SNR to 12. It fixed all of my problems. I now have 6.5 - 7mb stable connection.

What a waste of money and my time :) Anyway, resolved by BT.
 
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