[R-390] K. Alternate Procedure To Set The IF Gain Control

[Flowertime01 at wmconnect.com]

K. Alternate Procedure To Set The IF Gain Control

Once the receiver has been fully mechanically and electrically aligned, the 
final procedure to perform before "buttoning it up" is to set the IF gain 
control. The manual specification to set the IF Gain control for a level of 
-7 volts on the diode load for 150uv @455kc into J-513 is far too hot. Many 
otherwise very sensitive R390A's are thought not be hearing weak signals, 
because these signals are covered by excess noise generated in the IF module. 
The most common single item responsible for holding an R390A back is not lack 
of sensitivity. Rather it is internally generated IF deck noise.

___ 01 Allow the receiver to warm up for at least 1 hour then:
___ 02 Terminate the antenna input (just ground the balanced inputs)
___ 03 Set receiver for 15.2 MHz (Selected point of mechanical alignment)
___ 04 Set the "FUNCTION" switch to MGC
___ 05 Select the 4kc filter with the "BANDWIDTH"
___ 06 Set "RF GAIN" control to 10 or maximum
___ 07 Peak the "ANTENNA TRIM" for maximum noise
___ 08 Use the "LINE LEVEL" meter for peaking noise
___ 09 Set "Line Meter" switch to -10db scale
___ 10 Set "Line Gain" control to full CW or "10."
___ 11 Adjust IF gain control, R-519 to between -4 to -7 VU on Line Meter
___ 12 Set the "FUNCTION" switch to AGC
___ 13 Re-zero the carrier meter control, R-523
___ 14 Set controls above for normal operation
___ 15 Remove antenna short and reinstall antenna
___ 16 Power up the oven and verify function of the thermostat
___ 17 Turn the oven off
___ 18 Leave receiver on for at least 14 days to reform caps
</HTML>