11-08-2015, 04:54 PM
There was some confusion about the valve line up.
I have looked at the data sheet for the N78.
http://www.r-type.org/exhib/aaa0341.htm
I have worked out the value for the resistor and come up with a figure of 150 to 180 ohms. the voltage here should be between 5 and 6 volts.
This resistor should be connected to p1n 2.
Pin 1 is G1 and should be close to 0 volts and no more than 0.5 volts.
The capacitor on pin 1 must be replaced if the voltage is more than 0.5 volts as this will make the anode volts low and cause the valve to get too hot.
The old resistor has indeed been hot.
I have looked at the data sheet for the N78.
http://www.r-type.org/exhib/aaa0341.htm
I have worked out the value for the resistor and come up with a figure of 150 to 180 ohms. the voltage here should be between 5 and 6 volts.
This resistor should be connected to p1n 2.
Pin 1 is G1 and should be close to 0 volts and no more than 0.5 volts.
The capacitor on pin 1 must be replaced if the voltage is more than 0.5 volts as this will make the anode volts low and cause the valve to get too hot.
The old resistor has indeed been hot.
