No broadband unless I am using the housephone

[#1]

Anyone had this before, my girlfriend has had plusnet bb since 20th Jan and on the 27th of Jan she could not get connected, we have since deduced that the router only connects while the housephone is dialing or on a call, thens drops out as soon as the call finishes. We have made phonecalls to the helpline and all we get is can you change the microfilter or router which it clearly isn't or we would not be able to get broadband while the phone is been used.
I did find this
received judgement seems to be that if you need to make a call to get the broadband working, then somewhere along the line there is a dry joint - i.e. metal-to-metal contact is not perfect at some joint or plug connection.
The up to 50 volts used by the PSTN (normal landline calls) can burn through the dirt enough to assist the relatively puny ADSL signal to make contact. The problem is sometimes BT's PSTN tests will actually re-make the dry joint temporarily so no problem shows up in the test. It should still show high loop resistance in the test, but the resistance may be swamped by the resistance of the rest of the good copper wire.
I have to say after joining plusnet on the 14th Dec and makign 2 payments already for 7 days of working broadband is very poor.

[#2]

Have you actually tried changing the filter?

[#3]

Kitz's advice includes your "dry joint" theory but also that the filter or internal wiring could be the cause (as other sites also suggest.)

[#4]

We have tried another filter but no avail, going to try my filter in it too but now it will not even connect when the phone is in use, but I am guessing as the line is under test that maybe why.

[#5]

Though inconvenient it's probably an advantage if the problem stays like that. Something for the BT engineer to find and fix. Is the router plugged into the test socket (via a filter) to eliminate internal wiring?

[#6]

It does sound like you've got a fault, but you need to eliminate the filter, internal wiring, router etc before we can raise it through to get looked at.  This is to prevent you being hit by charges if an engineer is sent out and it ends up being one of those things.
Call us back up once you've done that and we'll get it sorted for you.

[#7]

In my experience these faults are usually a jumpering issue at the exchange, usually where after the line splits between the PSTN and broadband networks where it's connected to the line card.
If it saves you time log a fault here: https://portal.plus.net/apps/kbdfaults then reply to this post as soon as you have or drop me a PM and I'll get things going (provided you've done what you can to rule out your own router and filters).