[R-390] R390_Inspection_List_part_3

Wed Sep 12 15:52:50 EDT 2012

J Adjust the IF gain R519
___ 01 Set the Line Meter OFF
___ 02 Set the Line gain to 0
___ 03 Set the ANT Trim to 0
___ 04 Set the AGC to MED
___ 05 Set the LIMITER to OFF
___ 06 Set the Band Width to 2KHz
___ 07 Set the BFO Pitch to 0
___ 08 Set the Audio Response to WIDE
___ 09 Set the Breakin OFF
___ 10 Set the Function to MGC
___ 11 Set the BFO to OFF
___ 12 Release the Zero Adjust
___ 13 Release the Dial Lock
___ 14 Set the Local Audio to max
___ 15 Set the RF to max
___ 16 Remove P114 from J514
___ 17 Remove P213 from J513
___ 18 Remove P218 from J518
___ 19 Remove J116 adapter from the back panel if necessary
___ 20 Couple P114 to J513
___ 21 Couple P116 to J116
___ 22 Couple J116 to the signal generator RF output
___ 22 Adjust signal generator for 455 KHz output frequency
___ 24 Adjust signal generator for 150 micro volt RF output 
___ 25 Adjust signal generator for 30 % audio tonemodulation (400 Hz)
___ 26 Meter diode load output for –7 volts DC
___ 27 Place a 600 ohm load across the local audio output
___ 28 Place a 600 ohm load across the line audio output
___ 29 Meter local audio output for 450 milliwatts, 27 db, or17.3 Volts AC
___ 30 Adjust the IF gain R519 for –7 V DC on the diode load
___ 31 Observe the local audio output level is greater than400 milliwatts
___ 32 Local Audio should be 17.3 Volts AC across 600 Ohms450 mw
___ 33 Line Audio should be 2.45 Volts AC across 600 Ohms 10mw
___ 34 Phone Audio should be .78 Volts AC across 600 Ohms 1mw
___ 35 Line Audio at .78 Volts across 600 should be LineMeter Zero VU
___ 36 Set the Line Meter to +10
___ 37 Set the signal generator modulation on
___ 38 The Line Meter should read above 0 VU (10 mw)
___ 39 Set the Line Gain off max until the Line Meter reads0 VU (10 mw)
___ 40 Set the signal generator modulation off
___ 41 Set the Meter Switch to –10
___ 42 Observe 30 db change (20 db on switch plus 10 db onmeter scale)
___ 43 The Line Meter should read less than –10 VU (SN + N> 30 DB)
___ 44 Set the Line Meter to OFF
___ 45 Set the Line Gain to 0

K. Alternate Procedure To Set The IF Gain Control

Once the receiver has been fully mechanically andelectrically aligned, the final procedure to perform before "buttoning itup" is to set the IF gain control. The manual specification to set the IFGain control for a level of –7 volts on the diode load for 150uv @455kc intoJ-513 is far too hot. Many otherwise very sensitive R390A's are thought not behearing weak signals, because these signals are covered by excess noisegenerated in the IF module. The most common single item responsible for holdingan R390A back is not lack of sensitivity. Rather it is internally generated IFdeck noise.

___ 01 Allow the receiver to warm up for at least 1 hourthen:
___ 02 Terminate the antenna input (just ground the balancedinputs)
___ 03 Set receiver for 15.2 MHz (Selected point ofmechanical 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 peakingnoise
___ 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 VUon 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 thethermostat
___ 17 Turn the oven off
___ 18 Leave receiver on for at least 14 days to reform caps

L IF Module Alignment
___ 01 Continue with the prior setup
___ 02 Adjust signal generator for 455 KHz output frequency
___ 03 Adjust signal generator for 150 micro volt RF output 
___ 04 Adjust signal generator for 30 % audio tonemodulation (400 Hz)
___ 05 Meter diode load output for –7 volts DC
___ 06 Place a 600 ohm load across the local audio output
___ 07 Meter local audio output for 450 milliwatts, 27 db,or 17.3 Volts AC
___ 08 Set the Band Width to 2 KHz
___ 09 Adjust C571 (Top Trimmer) for max diode load output
___ 10 Adjust C513 (Bottom Trimmer) for max diode loadoutput
___ 11 Set the Band Width to 4 KHz
___ 12 Adjust C570 (Top Trimmer) for max diode load output
___ 13 Adjust C514 (Bottom Trimmer) for max diode loadoutput
___ 14 Set the Band Width to 8 KHz
___ 15 Adjust C568 (Top Trimmer) for max diode load output
___ 16 Adjust C515 (Bottom Trimmer) for max diode loadoutput
___ 17 Set the Band Width to 16 KHz
___ 18 Adjust C569 (Top Trimmer) for max diode load output
___ 19 Adjust C516 (Bottom Trimmer) for max diode loadoutput

M. To Stager Or Not To Stager
___ 01 Continue with the prior setup
___ 02 Set the Band Width to 16 KHz
___ 03 Set the Function to MGC
___ 04 Adjust signal generator for 455 KHz output frequency
___ 05 Adjust signal generator for 150 micro volt RF output 
___ 06 Adjust signal generator for 30 % audio tonemodulation (400 Hz)
___ 07 Meter diode load output for –7 volts DC
___ 08 Note the position of the top slug in T501
___ 09 Adjust the top slug of T501 for maximum output
___ 10 Return the top slug in T501 to its original position
___ 11 Adjust signal generator for 467 KHz output frequency
___ 12 Adjust the top slug of T501 for maximum output
___ 13 Note the position of the top slug in T501
___ 14 If the slug was tuned closer to 467 than 455 themodule is staggered
___ 15 If the module is to be stagger tuned then use thestagger tune steps

N. To Stager Tune IF
___ 01 Adjust signal generator for 467 KHz output frequency
___ 02 Adjust the top slug of T501 for maximum output
___ 03 Adjust the bottom slug of T502 for maximum output
___ 04 Adjust signal generator for 443 KHz output frequency
___ 05 Adjust the bottom slug of T501 for maximum output
___ 06 Adjust the top slug of T502 for maximum output
___ 07 Adjust signal generator for 455 KHz output frequency
___ 08 Adjust the bottom slug of T503 for maximum output
___ 09 Adjust the top slug of T503 for maximum output

O. To Straight Tune IF
___ 01 Adjust signal generator for 455 KHz output frequency
___ 02 Adjust the top slug of T501 for maximum output
___ 03 Adjust the bottom slug of T501 for maximum output
___ 04 Adjust the top slug of T502 for maximum output
___ 05 Adjust the bottom slug of T502 for maximum output
___ 06 Adjust the bottom slug of T503 for maximum output
___ 07 Adjust the top slug of T503 for maximum output

P. Adjust Z503 AGC
___ 01 Contiune from part J above
___ 02 Set the function switch to AGC
___ 03 Meter the AGC voltage for –1 to –2 volts on the AGCjumper
___ 04 Adjust the signal generator for an AGC voltage in themeter range
___ 05 Adjust Z503 for maximum AGC voltage on the AGC jumper
___ 06 Set the function switch to MGC