A new modem won't fix this will it?

[brundles]

I thought I knew a bit about the basics of the cable network but it would seem the faults guys on the phone today don't agree.

I've been suffering from intermittent losses of service on the broadband for a couple of weeks now. Every time it happens, the modem (SB4100) eventually recovers (minutes to hours later during which point it can't settle on the upstream and the TX light on the modem sits there flashing) and shows an upstream power level of 58dBMV - a level I'd been led to believe was far too high. During the outage period, the on-demand services on the TV also don't work and occasionally the TVDrive online light flashes as it loses it's connection.

All of this was relayed to the faults people who proceeded to bounce me between TV and Broadband faults (never tell them it's affecting the other service even though you know it helps diagnostics!) until I got one guy who helpfully told me it was the wireless in my router doing this :confused: He's since changed to "it's caused by the modem forgetting it's config" and won't do anything about an engineer booking until the new modem he's ordered arrives and is installed.

My (admittedly limited) knowledge and experience tells me that the new modem won't have any effect. Can anybody pacify me and explain why it will fix it?

Please :D

[Toto]

I believe that if the levels to your property are not what they should be, then yes a new modem wouldn't fit the bill.

What speed are you on BTW, because I had to change my SB4100 for an Ambit 255 to get 20Mbps.

[brundles]

I believe that if the levels to your property are not what they should be, then yes a new modem wouldn't fit the bill.

What speed are you on BTW, because I had to change my SB4100 for an Ambit 255 to get 20Mbps.

I'm on the 10meg package. When the modem works I tend to get top speed all the time (STM periods excepted of course) - it just refuses to come below 56dBmV for the upstream signal.

[Toto]

I'm on the 10meg package. When the modem works I tend to get top speed all the time (STM periods excepted of course) - it just refuses to come below 56dBmV for the upstream signal.

Ahh, 10Mb, that's fine with that modem, hopefully somebody more qualified than me will come along soon and offer some advice.

[Joxer]

58 is too high, you need a tech.

Phone back (when it goes off) and hope you get someone sensible.

In answer to your original question, a new modem may fix it as some modem (for example the epc 2100) will cope with the power level up to 61 though what you really need is the power level brought down, either with an attenuator or possibly an adjustment/fix at the other end since high transmit power levels can be caused by overheating RF amplifiers.

[brundles]

Glad to see it's not just me that thinks this :)

I did raise the possibility of an upstream fault - even pointed them to the multiple engineer visits made about this time last year when the same thing happened. (It only got escalated to networks when the engineer kicked off at being able to predict his job sheet because the same 4 people around the area kept complaining whenever it happened.) But the response was just we'll send you a new modem and look at it again if that doesn't fix it. :(

[whydoIneedatech]

Glad to see it's not just me that thinks this :)

I did raise the possibility of an upstream fault - even pointed them to the multiple engineer visits made about this time last year when the same thing happened. (It only got escalated to networks when the engineer kicked off at being able to predict his job sheet because the same 4 people around the area kept complaining whenever it happened.) But the response was just we'll send you a new modem and look at it again if that doesn't fix it. :(
I would have booked a tech and advised him to replace the modem as well has resolve that upstream power level for you.

[brundles]

Interesting - what's the reason for the modem change? The engineer last year reckoned the SB4100 was one of the more robust modems when it came to network connectivity and keeping going.

You've got a good reputation on this board and I'm not asking to be difficult, I just like to understand these things :)

[whydoIneedatech]

Interesting - what's the reason for the modem change? The engineer last year reckoned the SB4100 was one of the more robust modems when it came to network connectivity and keeping going.

You've got a good reputation on this board and I'm not asking to be difficult, I just like to understand these things :)
You needed a tech to sort out the power level and the SB4100 can struggle at 10Mb so would advise replacement as it cannot support 20Mb.

Better to nip it in the bud now rather than later.

[brundles]

Fair enough - that makes sense. Although it's never had any problems I guess it's easier to have the tech swap the modem for future proofing while he's here anyway.

Now about that tech appointment - any chances of a booking? ;)

[whydoIneedatech]

Fair enough - that makes sense. Although it's never had any problems I guess it's easier to have the tech swap the modem for future proofing while he's here anyway.

Now about that tech appointment - any chances of a booking? ;)

Yes just ring in:D

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[chickendippers]

Or post your signal levels in the virginmedia.support.broadband.cable newsgroup (http://www.virginmedia.com/customers/newsgroups/) and they'll have an engineer booked for you in no time.

[brundles]

New modem has arrived and in - Joxer was right about the 61bDmV - that's what it's sync'd on now. If it works I'm not too fussed what level it's at but I think when the fault starts again I'll go for the newsgroups as chickendippers mentioned. (Although I seem to remember that group got the short straw didn't they?)

[darkbeing]

Hey I had this exact problem for a long time (2 years) intermittently, and I just couldnt figure it out - then one day when it happened I got a bit angry with it and rammed the cable tighter into the end plug connector while it was still attached to the modem - and held it there.
then the broadband worked. So I went to maplin bought a new connector terminal and cut a metre off the cable and fixed the new one on - since then absolutely no problem.

[XFS03]

New modem has arrived and in - Joxer was right about the 61bDmV - that's what it's sync'd on now. If it works I'm not too fussed what level it's at but I think when the fault starts again I'll go for the newsgroups as chickendippers mentioned. (Although I seem to remember that group got the short straw didn't they?)
61dBmV is the absolute maximum signal that the modem can return. It is working flat out (58dBmV is the maximum for the 4100). I think the chances of it working reliably are pretty slim.
...what you really need is the power level brought down, either with an attenuator...
An attenuator would make it worse. The modem ramps up it's signal output until the UBR sees a satisfactory level. As it's already working flat out, an attenuator would stop the modem working completely.

As darkbeing suggested, the only thing you can do yourself is to check the coax cable. I know mine has come loose at the white box end in the past, causing problems.

.

[Joxer]

61 is too high you need a tech, preferably one who knows what he is doing.

[brundles]

From past experience, the trick isn't so much getting a tech out that knows what they're doing but getting someone on the end of the phone that knows what they're doing to get the tech booked. As I mentioned earlier in the thread, all providing lots of information did was get me bounced around different faults departments. :(

Actually, that reminds me - does anyone know the time slots they run for the techs? The guy that sent the modem out said if a tech was required after the modem swap, there were slots later than 7pm (about the earliest I can be sure I'm home from work by) which didn't seem right.

[Joxer]

Slots are 08:00 to 12:00, 12:00 to 16:00 and 16:00 to 19:00, Monday to Friday, Saturday only morning or afternoon available - Sunday no slots. Some areas have slots on Sunday instead of Saturday, but not many (and possibly only occasionally).

[brundles]

That's what I thought - I didn't think VM paid their techs enough for a 7 to 10 type slot!