[R-390] R390_Inspection_List_Part_4B

Wed Sep 12 15:58:03 EDT 2012

S 2nd Crystal Oscillator Alignment
When adjusting the 2nd Crystal Oscillator you canhear the noise peak better than you can measure it with the meter. Peak thecaps up with both the meter and head phones.

___ 01 Meter the local audio output across a 600 Ohm load
___ 02 Meter the diode load for – 7 volts DC
___ 03 Use a good set of head phones to monitor the audiooutput
___ 04 Set the function switch to CAL
___ 05 Set the BFO OFF
___ 06 Set the KHz to 500
___ 07 Set the KHz to 31
___ 08 Set the Bandwidth to 2 KHz
___ 09 Rock the KHz to produce maximum indication on thediode load
___ 10 Set the Local Output meter range to provide a midscale reading
___ 11 Use the head phones to hear the noise peak as youmake adjustments
___ 12 Screw the slug of T401 out until only one peak can beobtained while turning trimmer capacitor 31 through its entire range.
___ 13 Set trimmer capacitor slightly away from peak
___ 14 Adjust the slug in T401 for peak output
___ 15 Readjust capacitor 31 and ensure it has two peaks.
___ 16 Adjust capacitor 31 to peak (watch the meters for bestindication)
___ 17 Move the MHz down one detent (you can hear the noisepeak)
___ 18 Adjust the corresponding capacitor to peak
___ 19 Stop at 8MHz

T 1st Crystal Oscillator Alignment
___ 01 Meter the local audio output across a 600 Ohm load
___ 02 Meter the diode load for – 7 volts DC
___ 03 Use a good set of head phones to monitor the audiooutput
___ 04 Set the function switch to CAL
___ 05 Set the BFO OFF
___ 06 Set the KHz to 500
___ 07 Set the MHz to 7
___ 08 Set the Bandwidth to 2 KHz
___ 09 Rock the KHz to produce maximum indication on thediode load
___ 10 Adjust the slug in T207 for peak output

U VFO Band Spread Test
___ 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 to OFF
___ 10 Set the Function to CAL
___ 11 Set the BFO to ON
___ 12 Set the Zero Adjust to center
___ 13 Release the Dial Lock
___ 14 Set the Local Audio to max
___ 15 Set the RF to max
___ 16 Set the KHz knob to -000
___ 17 Adjust the BFO Pitch to zero beat
___ 18 Set the KHz knob to +000
___ 19 Rock the KHz knob to zero beat
___ 20 The VFO band spread should be less than 300 Hertz

V VFO Band Spread Adjustment
___ 01 If needed continue from the preceding section
___ 02 Set the FUNCTION switch to CAL
___ 03 Set the MHz to 9 MHz
___ 04 Set the Zero Adjust to center
___ 05 Set the KHz knob to 000
___ 06 Remove the Oldham coupler spring
___ 07 Remove the VFO from the receive
___ 08 Remove the end point adjustment cap screw
___ 09 Attach the output cable and harness cable
___ 10 Adjust the VFO shaft for a zero beat
___ 11 Mark the coupler and VFO face (9,000 3,455)
___ 12 Set the KHz knob for 9,+000 (9,+000 2,455)
___ 13 Dial 10 turns on the VFO shaft and align the marks
___ 14 If the span is not exact make a small adjustment tothe end point
___ 15 Do not over adjust the end point to a complete zerobeat
___ 16 Observe the pitch is closer to zero beat
___ 17 Back off the 10 turns on the VFO shaft (only work oneway)
___ 18 Set the KHz knob to 000
___ 19 Adjust the VFO shaft for a zero beat
___ 20 Mark the coupler and VFO face (9,000 3,455)
___ 21 Set the KHz knob for 9,+000 (9,+000 2,455)
___ 22 Dial 10 turns on the VFO shaft and align the marks
___ 23 If the span is not exact make a small adjustment tothe end point
___ 24 Do not over adjust the end point to a complete zerobeat
___ 25 Observe the pitch is closer to zero beat
___ 26 Repeat steps 17, 18, 19, 20, 21,22, 23, 24 and 25until span is exact
___ 27 Make a small adjustment to the end point (CW longerCCW shorter
___ 28 Do not over adjust the end point to a complete zerobeat
___ 29 replace the end point cover screw
___ 30 Return the VFO shaft to its original location
___ 31 Reinstall the VFO into the receiver
___ 32 Carefully verify the 10 turn operation of the VFO
___ 33 Adjust the mechanical position of module for bestshaft alignment
___ 34 Adjust the Oldham coupler for a free spacing ofshafts
___ 35 Replace the Oldham coupler spring
___ 36 Attach an antenna to the balanced input
___ 37 Tune WWV at 20MHz, 15Mhz, 10MHz or 5Mhz
___ 38 Set the BFO to OFF
___ 39 Set the bandwidth to .1Khz
___ 40 Set the KHz to 000
___ 41 Loosen the front KHz shaft clamp on the Oldhamcoupler
___ 42 Rock the VFO to peak WWV through the crystal filter
___ 43 Tighten the front KHz shaft clamp on the Oldhamcoupler
___ 44 Set the BFO to ON
___ 45 Set the BFO Pitch to 0
___ 46 Loosen the extension shaft clamp on the BFO
___ 47 Adjust the BFO shaft to zero the BFO Pitch
___ 48 Tighten the extension shaft clamp on the BFO
___ 49 Set the FUNCTION Switch to CAL
___ 50 Adjust the CAL Adjust Trim to zero the CalibrationOscillator

W. RF Alignment

___ 01 Install a 600 ohm resistor on the line level output.
___ 02 Place a meter and 600 ohm load on the Local Audiooutput TS 585
___ 03 Connect the generator to the receiver’s balancedantenna input
___ 04 Place a DC meter on the diode load
___ 05 Turn the receiver on and allow it to warm up for 1hour
___ 06 Turn the signal generator on and allow it to warm upfor 1 hour
___ 07 Set the R390 or R390A Function switch to "MGC
___ 08 Set the R390 or R390A Bandwidth to 2kc
___ 09 Set the R390 or R390A RF gain full CW (Clock Wise)
___ 10 Set the R390 or R390A AF line gain full CW
___ 11 Set the Line Meter range switch to + 10
___ 12 Set the R390 or R390A AF local gain full CW
___ 13 Set the R390 or R390A BFO off
___ 14 Set the Audio response to wide
___ 15 Set the Limiter to off
___ 16 Set the receiver and generator to the same frequencyof choice
___ 17 Rock the generator for a peak in to the band pass
___ 18 Set the initial generator output to 10uv
___ 19 Set the generator modulation level to at 30% 400 Hz or1 KHz
___ 20 Use the Ant Trim to peak the receiver
___ 21 Reduce the signal generator RF output for –7 volts DC

___ 22 Use 550 for L213, L224-1,, L224-2 Slugs 1stOctave
___ 23 Use 950 for C201-B, C230-1, C230-2 Caps 1stOctave
___ 24 Use 1,100 for L215-1, L215-2, L215-3 Slugs 2ndOctave
___ 25 Use 1,100 for C291-1, C291-2, C291-3 Caps 2ndVariable IF
___ 26 Use 1,250 for L232-1, L232-2, L232-3 Slugs 1stVariable IF
___ 27 Use 1,900 for L233-1, L233-2, L233-3 Slugs 2ndVariable IF
___ 28 Use 1,900 for C205-B, C233-1, C233-2 Caps 2ndOctave
___ 29 Use 2,250 for L217, L226-1, L226-3 Slugs 3rdOctave
___ 30 Use 3,800 for C209B, C236-1, C26-2 Caps 3rdOctave
___ 31 Use 4,400 for L219, L227-1, L227-2 Slugs 4thOctave
___ 32 Use 7,250 for C283-1, C283-2, C283-3 Caps 1stVariable IF
___ 33 Use 7,600 for C213B, C239-1, C239-2 Caps 4thOctave
___ 34 Use 8,800 for L221, L227-1, L227-2 Slugs 5thOctave
___ 35 Use 15,200 for C217B, C242-1, C242-2 Caps 5thOctave
___ 36 Use 17,600 for L223, L229-1, L229-2 Slugs 6thOctave
___ 37 Use 30,400 for C221B, C241-1, C241-2 Caps 6thOctave

___ 38 Observe 27 DB (17 Volts AC) on the Local Audio
___ 39 This should also be 450 milliwatts on the Local Audio
___ 40 Observe + 10 on the Line Meter (0 VU + 10 switch)
___ 41 Set the signal generator to CW
___ 42 The Meter on the Local Level should drop 20 DB
___ 43 The Line Meter should drop 20 DB
___ 44 The signal generator RF level should be less than 3micro volts
___ 45 Record the frequency and the output of the generatorin micro volts
___ 46 This value is the 20 DB S/N + N receiver level atthis frequency
___ 47 This is the relative receiver noise floor level atthis frequency

___ 48 Use the following check the mechanical filters at onefrequency
___ 49 Set BANDWIDTH KC switch S501 to position 1.
___ 50 Adjust the signal generator output for -5 volts onthe diode load
___ 51 Tune the KILOCYCLE CHANGE to one side of the center
___ frequency until the multi-meter reads 2.5 volts.
___ 52 Note the frequency indicated on the receiver frequencycounter.
___ 53 Tune the receiver KILOCYCLE CHANGE control to theother side
___ of the center frequency until the meter reads 2.5 volts.
___ 54 Note the frequency indicated on the receiverfrequency counter
___ 55 Subtract the lower from the higher of the two values
___ 56 This is the receiver bandwidth for 1 Kilohertz BandWidth 0.8 to 1.3
___ 57 Set BANDWIDTH KC switch S501 to 2 KHz position
___ 58 Repeat steps 50 through 55 for the 2 KHz band width1.9 to 2.3
___ 59 Set BANDWIDTH KC switch S501 to 4 KHz position
___ 60 Repeat steps 50 through 55 for the 4 KHz band width3.6 to 4.4
___ 61 Set BANDWIDTH KC switch S501 to 8 KHz position
___ 62 Repeat steps 50 through 55 for the 8 KHz band width7.5 or more
___ 63 Set BANDWIDTH KC switch S501 to 16 KHz position
___ 64 Repeat steps 50 through 55 for the 16 KHz band width12 or more
___ 65 No bandwidth test is required for 0.1 KC setting.