[russell_w_b]

I've just read your post #20 and am guessing you reconnected the handset as you had it originally before measuring across T4 and T5. I should've made clear that you should've either disconnected the handset from the phone or left it wired as I suggested. In the original state there'd've been 150 Ohm through the receiver and the ASTIC.

I suggest you check out your handset wiring for continuity and ensure there are no shorts between wires. Then wire the handset so you have three clearly identifiable handset wires available for connection to the telephone terminal block:

* A common mic / receiver wire to connect to terminal T5.
*A receiver connection to connect to terminal T6.
*A microphone connection to connect to terminal T4.

Leave it in this configuration, then we'll take it from there.