The main benefit of an NTE5A master socket is easy fault diagnosis, by simply removing two screws the end user can disconnect any internal extension wiring and plug directly into BT's network, thus proving where the fault lies.
However, with the introduction of the vDSL I plates fault diagnosis becomes a little more complicated to find whether the fault lies with the filter, wiring or the BT line itself. Read on to find what is causing the problem.....
First off, with just an NTE5A fitted:-
Remove the two screws, the lower front plate will unplug from the main socket :-
If you have any extensions fitted these should be wired to the back of this plate on connections 2, 3 & 5. Don't worry if there are any extra connections with or without wires in them-they aren't used. With the lower front plate off you will see the NTE5A test socket :-
With the test socket revealed it's important to check all extensions are DEAD. If they aren't then this indicates your extensions are not wired from the master socket, this is not good for broadband and also means any fault could still be caused by internal wiring, in other words NOT BT's problem!
Assuming everything is wired up correctly plug a telephone into the test socket, if you have broadband do this via a filter. If your telephone & broadband now work then the fault is either with internal extension wiring or the master socket itself. Obviously if you have no extensions then it can only be the NTE5A itself faulty. If the telephone is dead but the broadband works slowly then this indicates one of the incoming wires is broken or has a bad connection.
Moving on to the NTE5A with vDSL faceplate, your socket will look like this (Note some are marked Mk2 & Mk3-these are just different revisions of the design) :-
As above there are two screws holding the front on, again remove these two screws (these are much longer than just the NTE5A as they pass through the vDSL plate), remove the small lower front plate (same as with just the NTE5A) but leave the vDSL plate fitted, as there aren't any separate screws holding this plate to the back plate you may have to hold it in place while testing. With the small lower front plate removed you will see the vDSL plate test socket :-
Again any telephone extensions should now be dead. If your telephone now works this indicates your extension wiring could be at fault, if there are no extensions fitted then the lower front of the NTE5A is faulty-replace the NTE5A. If the telephone does not work then the vDSL plate is faulty-replace the vDSL plate. If the broadband does not work while plugged into the top socket then this indicates the vDSL faceplate is faulty or there is a line fault. To find out which is the case remove the vDSL faceplate from the back plate & test again in the NTE5A test socket. You will need to use a plug in filter in the NTE5A test socket. If the broadband now works the vDSL plate is faulty. If a telephone also now works then this confirms the vDSL plate is faulty-replace the vDSL plate.