Yo-yo sync rate

[#1]

After raising a fault and it being quickly fixed, the issue of poor broadband speeds seems to have popped it's head up again.
After almost a month of faultless 6Mbs speeds and a sync rate of 7.2, my sync rate seems to be rising and falling like a yo-yo with no tie to Noise threshold. The connection will also drop at high and low sync rates.
My question is does the router continually monitor the line rate or except the first sync rate after connection until the connection is lost? As my profile has now been pulled down again and even when I achieve the high sync rate my profile stays low unless I can maintain the high sync rate for 24hours.

[#2]

On ADSL1 the profile drops almost immediately after a lower sync event, but takes "up to 72 hours" to adjust upwards for a higher sync (unfair, but true.)
On ADSL2 the profile adjusts instantly with each change in sync speed, although other "adjustments" might be made to your connection settings if the drops are frequent.
Don't think that is of much significance at the moment though with your connection - it's unexplained drops which are your main problem and suggest some sort of fault has developed.
Probably a good idea to go through the standard user-end checks (filters,master socket, different router if possible) as you will have to do them anyway if you raise a fault.

[#3]

HI drneil,
Your SNR is currently 15dB, so that won't help. Also, can you tell me if you're using any extension cables/sockets? Do you have a test socket you can plug into?
Jojo

[#4]

Jo
The sync rate has been up and down since Friday, after nearly a month of stable connection at 7.3 sync rate. SNR has also risen since then, but the connection has been unstable. The connection is into the master socket, tried with two different routers, with two different link link cables and filters.
When the engineer came the last time the connection was stable at 7.3, so I assume it maybe a intermittent problem. Just strange that it stays stable for weeks. Can we try resetting the SNR or is anything we can do set a target SNR?

[#5]

Do you not have a test socket?

[#6]

Sorry Jo, I call it the master socket. yes I have the front panel removed and plugged in directly,as shown on your photo, its one of the first things I tried.

The Openreach engineer also replaced this on his last visit not due to a fault but due to the fact mine was old. With the front panel on I was getting a SNR of 8 since his visit until last friday.

[#7]

Leave it in the test socket, I'll reset the SNR and we'll see how it holds up