Wilfred.. thanks for your help once again.
Where did you find the schematics for the t-2000.
The two schematics you posted appear to be the same, just drawn about face from the 2nd op-amp to the right
The power rails are swapped and components moved about and some rotated, but the circuits seem to be the same.
One shows the iron connected with a plug and socket.
The PCB layout is completely different.
On the PCB there are 5 trim pots. 3 flat to the board and 2 upright.
I will try to trace the circuit but there a lot of wires on the board and make it hard to keep flipping the board over.
see attachments.
I will give it as go anyway, maybe I could use the pictures to help..
Thanks for your help.
BILL