Router instability

I have a Netgear DG834N router that has for some time been losing sync now and again. Sometimes, it will perform for a week or so without any trouble, and at other time it will lose sync several times in a day. I've always put it down to line noise or the OR engineers mucking about.

However, this evening it really started playing up. Usually, I just reboot it from the web interface but this time it didn't do the job, so I decided to do a hard boot. I unplugged the power cord, waited a few seconds and then plugged it back in, and I noticed that the LEDs didn't behave as they should do. I tried it again and as I repeated the process, things got progressively worse until the wretched thing refused to boot at all.

Maybe I've killed it, I thought, and wondered if the old Westell modem that I kept for such emergencies would still work, or if I would have to resort to dial-up, and how would I find out how to do it unless I could get back on-line. Eventually, it dawned on me to check the power brick. It should be reading 12V (assuming it's regulated) but, no, it read 17 volts and some. I plugged in another PSU have the router has been fine so far.

The sync speed had dropped to 9.6 kbps whereas it should be around 14 kbps. Maybe it will re-train. I'm not sure whether to switch it off overnight or leave it switched on, or do I have to call BT to have the noice margin reset? Current readings are:

Down               Up
Connection Speed:     9623 kbps     1163 kbps
Line Attenuation:          32.0 db          16.5 db
Noise Margin:                 7.8 db            6.3 db

The downstream margin was at 16db earlier on so this has improved already but the sync speed hasn't changed.

Any recommendations?

Edited by micksharpe (Wed 10-Jun-15 00:25:50)

Try for a profile reset, I think. Switching it off at all will probably make things worse, as the exchange will interpret it as instability.

The router seems stable so I'll leave it switched on. The noise margins are bouncing around a bit so the next task is to check the house wiring before I call BT.

Just had loss of sync again so it's not the power brick.

In reply to a post by micksharpe:

Eventually, it dawned on me to check the power brick. It should be reading 12V (assuming it's regulated) but, no, it read 17 volts and some. I plugged in another PSU have the router has been fine so far.

In reply to a post by micksharpe:

Just had loss of sync again so it's not the power brick.

Not necessarily- the (possibly) faulty power brick could have cooked something in the router so swapping it out has only stopped it progressing from medium rare to well done�

Only reliable test is to swap out the router, that's why I always have a spare.

Don't entirely agree with Camie about switching off- it should send a "last gasp" signal to the DSLAM so the DLM realises it's not a line problem. Otoh, I've never completely trusted this mechanism!

In reply to a post by billford:

Only reliable test is to swap out the router, that's why I always have a spare.

I have a 2700HGV as well as the Westell. It just needs unlocking and a new power brick. I'll give it a go -- I can use my bench PSU.