Having upgraded my 5065A with an improved AC Amplifier BoardI went along to also upgrade the A9 Integrator. I obtaineda few OPA111's and also found a what I beleive was anacceptable quality integrator capacitor. My prototype usedstandard 78xx and 79xx voltage regulators. When testing this board according to the service manualthe output voltage did not change between going fora mug of cofee and returning after having finished it. I take that as an "OK". The design did not go to well with the older type of OCXO though(Yes - I noticed Corbys warning about the resistor presenton the fp switch). So I did not install the board. Attached is a .PDF and a .JPG Comments invited. Ulf Kylenfall SM6GXV