[TMC] GPR90-RXD Receiver - Mod Info

[Mark Johnson]

TMC Team;
I just picked up a GPR90-RXD and while it is working, its not as good as it should be. I can see someone has been into it and done some modifications. The area I'm into now is the Oscillator V12 and the external oscillator, V17. Someone has added a diode and resistor in the circuit that connects the two. 

>From experience, its nice to have a description of popular modifications that may have been done so that reversing them is easier. I suspect like most gear, various mods where published in popular Ham publications of the day....

Can anyone help or point me to possible sources?

Many thanks

Mark V Johnson VE3DJU/VE3DDI