Loss of Broadband - 16 days and counting

Question

Over the past 2 months my broadband has got more unreliable to the point that in the last 16 days it has been virtually unusable.
I have a second broadband in to the house that is rock solid with no issues.
What seems to happen is that the SN margin for the downstream goes from it's normal 9db to 3 or even 0 or a minus figure and the CRC and HEC errors go through the roof and eventually after slowing to a crawl the broadband disconnects and remains that way.
I have tried a different hub, the filter has been changed to a 2000 type , an iplate was also tried with the original NTE and all internal wiring has been disconnected. Openreach have been out and changed the NTE and checked the line with their new "Hawk type" tester and declared the line clean but it is still the same.
What has not been changed or looked at as far as I can see is the DSLAM connection.
Rebooting the hub cures things for a little while as the Sn margin goes back up but I have stopped doing that in the hope someone not reading from script can find the problem.
I have rang the broadband helpdesk countless times over the past weeks , been told I will have a call back and apart from one I've never had one. In addition I have been asked to use a cable connection and reconfigure the hub to use a different "domain" and given a 0808 number and pin to access the "wholesale team" to have them look at the faults to be told it is progressing and then later on another call being advised it has never been passed to Wholesale and that number is for Wholesale.
Today's latest in the saga is that an "exchange" engineer appointment had been booked for Monday only for a call 3 hours later to say they can't do it and I'm to await a call on Monday to book an appointment so we shall see if this materialises.
Through all of this I have been unable to use BT Vision, which I pay a subscription for, as well as my Broadband phone to any degree.
As a customer I feel frustrated by the long drawn out saga and though the helpdesk are polite I can't seem to get anything moving to resolve the issue so if a mod is around I'd appreciate some help.
Latest hub stats below which shows disconnected and a steady amber broadband light. The hub has remained on and not rebooted to hopefully give someone a pointer.
DSL Connection
Link Information
Uptime:
1 day, 2:59:03
Modulation:
G.992.1 annex A
Bandwidth (Up/Down) [kbps/kbps]:
448 / 4,320
Data Transferred (Sent/Received) [MB/MB]:
15.71 / 338.59
Output Power (Up/Down) [dBm]:
11.5 / 19.5
Line Attenuation (Up/Down) [dB]:
31.5 / 49.0
SN Margin (Up/Down) [dB]:
19.0 / -1.4294967291
Vendor ID (Local/Remote):
TMMB / ALCB
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
Error Seconds (Local/Remote):
42,491 / 0
FEC Errors (Up/Down):
0 / 0
CRC Errors (Up/Down):
0 / 2,786,728
HEC Errors (Up/Down):
0 / 110,452
Line Profile:
Fast

Answer 1

Hi Stephanie
Well the engineers came and checked the line and could not see any issue with it.
The replacement hub that I had used to narrow down the issue was then rebooted and wouldn't sync so they tried their test hub and that worked. I was asked to put my origonal hub back on, the one I had removed some weeks ago as part of trying to diagnose this fault, and that worked so before leaving I was told that they would:
- Send out a replacement hub just in case.
- Recommend a lift a shift or rebuild of software to Wholesale. Though they did state that Wholesale might not do this as they could find no fault.
About an hour later the hub rebooted and I had 5.2Mb sync rate, 4.5Mb throughput and a SN margin of 18/6. This is as fast as it as the line has ever been. I'm not sure what was done at the exchange as I didn't get an update.
Sadly later that night whilst wtching something on Vision the video stream stalled and I got the same issues again in that the SN margin went down to this time 18/4.0 with lots of errors/loss of input/signal. This morning the sync speed is down to about 4.2Mb and throughput 1.94Mb and the SN margin is 18/9.
So no further forward really.
So either I've got 2 faulty hubs..unlikely though I suppose possible
The DSLAM was not lift and shifted or the software rebuilt as no fault could be found.
If the lift and shift or rebuild hasn't been done then can this be progressed?
The only other thing is that my line is permanently in fast mode due to previous attempts by BT to resolve isssue with my Vision service when it was in  Interleave mode. I suppose this could also be contributing to the issues?
I really do need this sorting and as I say I have another ADSL service in to the house and that is rock solid and sync's at over 5-6Mb.