Sudden big increase in CRC errors and SNR instability.

http://www.flickr.com/photos/banger_this/5376352002/

Last week phone was dead and BT came out and fixed it. It was a bad joint that had corroded and had water in it. Reported it as a Phone fault and it was fixed relatively quickly. The phone started off with a bad crackle then went dead but BB still worked although only at 2 meg, I usually get 8 meg.

Unfortunately now I have a problem with Broadband as can be seen from the above graph and title. My SNR is all over the place, been fine for a week, and CRC errors are racking up and making my router re-sync alot. The re-syncs are seemless and don't interrupt internet use but I don't want my target margin going up with too many re-syncs.

I've checked for interference locally but found nothing and the phone line doing the quiet line test sounds excellent so could it be REIN? Any suggestions to my next course of action? Will Zen/BT accept a fault if it's just re-sync'ing?

Update. Tried router on test socket and it started rebooting so now trying a spare router. Routers are Speedtouch 546 v6, spare one has been up 30 mins and no CRC errors. Either it's an intermittant noise problem or original router up the spout.

Further investigation of original router reveals 2 'domed' electrolytic capacitors each 1000mF 6.3v

Edited by Banger (Fri 21-Jan-11 22:37:00)

Ah the speedtouch achilies heel, dodgy cap's.

The make is CapXon. Is this a common problem as I have just ordered some high temperature replacements from Maplin but it doesn't specify make. Only 2 caps are bulging going over to BadCaps.net for more info.

All down to poor thermal design and cheap caps's. So long as you get replacements which are rated at a higher voltage you should be ok.

Cheers for that. Ordered some Panasonics at higher voltage and temp rating from RS now.

Opened up my spare router and exactly the same caps are bulging on the tops. Just as well I ordered extra caps. Now monitoring the line for CRC bursts. Looks like both routers will need new caps.

So far so good. Have recapped both 546v6 routers, just the power supply caps of 1000uF 16v, 2 each, and no CRC errors over two short 15 min tests. Replaced the bad CapXon caps with Panasonics, originals were 6.3V have replaced with 16v caps to allow plenty of headroom. Now to test for a week each, am hoping this is a permanent fix.

3 days 5 hours uptime and only 95 CRC errors so to close this thread off I think I can say the recapping did the trick with new Panasonic Caps.