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Standard User Banger
(eat-sleep-adslguide) Fri 21-Jan-11 20:57:38
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Sudden big increase in CRC errors and SNR instability.


[link to this post]
 
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?

Tim
ZeN & freenetname
ST546v6 on 8 Meg Active
Check my bad boy speeds out on ZeN
Standard User Banger
(eat-sleep-adslguide) Fri 21-Jan-11 22:25:43
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Re: Sudden big increase in CRC errors and SNR instability.


[re: Banger] [link to this post]
 
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

Tim
ZeN & freenetname
ST546v6 on 8 Meg Active
Check my bad boy speeds out on ZeN

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

Standard User Rockh
(eat-sleep-adslguide) Fri 21-Jan-11 22:51:32
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Re: Sudden big increase in CRC errors and SNR instability.


[re: Banger] [link to this post]
 
Ah the speedtouch achilies heel, dodgy cap's.

Dave


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Standard User Banger
(eat-sleep-adslguide) Fri 21-Jan-11 22:59:49
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Re: Sudden big increase in CRC errors and SNR instability.


[re: Rockh] [link to this post]
 
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.

Tim
ZeN & freenetname
ST546v6 on 8 Meg Active
Check my bad boy speeds out on ZeN
Standard User Rockh
(eat-sleep-adslguide) Fri 21-Jan-11 23:12:17
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Re: Sudden big increase in CRC errors and SNR instability.


[re: Banger] [link to this post]
 
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.

Dave
Standard User Banger
(eat-sleep-adslguide) Fri 21-Jan-11 23:46:39
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Re: Sudden big increase in CRC errors and SNR instability.


[re: Rockh] [link to this post]
 
Cheers for that. Ordered some Panasonics at higher voltage and temp rating from RS now.

Tim
ZeN & freenetname
ST546v6 on 8 Meg Active
Check my bad boy speeds out on ZeN
Standard User Banger
(eat-sleep-adslguide) Sat 22-Jan-11 03:14:16
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Re: Sudden big increase in CRC errors and SNR instability.


[re: Banger] [link to this post]
 
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.

Tim
ZeN & freenetname
ST546v6 on 8 Meg Active
Check my bad boy speeds out on ZeN
Standard User Banger
(eat-sleep-adslguide) Tue 25-Jan-11 15:46:02
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Re: Sudden big increase in CRC errors and SNR instability.


[re: Banger] [link to this post]
 
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.

Tim
ZeN & freenetname
ST546v6 on 8 Meg Active
Check my bad boy speeds out on ZeN
Standard User Banger
(eat-sleep-adslguide) Fri 28-Jan-11 20:53:12
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Re: Sudden big increase in CRC errors and SNR instability.


[re: Banger] [link to this post]
 
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.

Tim
ZeN & freenetname
recapped ST546v6 on 8 Meg Active
Check my bad boy speeds out on ZeN
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