Ithaco 1201 modification
The 1201 has an issue with a highly varying DC-offset due to leakage currents around the high-impedance node that includes the gate of Q58.
In order to protect the node and improve the DC-offset the connection was re-arranged: First, the gate of Q58 was disconnected by cutting the track close to the gate. The track was also cut in the other end, close to TP8, and was then connected to ground. The gate of Q58 was then connected by a separate wire to the node of TP8. In order to cut the PCB track close to TP8 and to connect the PCB track to ground the 1 kOhm resistor next to TP8 was moved to the bottom of the PCB. |