PC-893 PCB

Stalker 9F-DX, and others that use the PC-893 PCB

If you know of others please let me know !

This alignemnt procedure was taken from an old service manual I had around for the Stalker ST 9F-DX, do not confuse this radio for the Stalker IX, they look almost identicle but they use different PCB's, I have the alignment for the IX in the alignment section.

GENERAL ALIGNMENT INFO

All adjustments are made with the radio set radio to CH19 on the FCC band unless otherwise stated.

Make sure that the clarifier is centered

 

You will need:

A good frequency counter with a 10Hz resolution

The proper (plastic / ceramic) adjustment tools.

A 50MHz oscilloscope (although a 30MHz will do).

50 Ohm dummy load.

Alignment of PLL and Carrier Oscillator:

 

Preset to: Adjustment: Comments:

Channel: 40

Mode: AM, RX.

Band: Low

 L16

Connect oscilloscope to TP4 (lead of R112).

Adjust L16 for maximum signal level.

Channel: 40

Mode: AM, RX.

Band: Hi		 L17

Connect DC Volt meter to TP2 (lead of R117).

Adjust L17 to obtain a 5.5 Volt reading, confirm that it is above 2 Volts in low band on channel 1.

Channel: 40

Mode: AM, RX.

Band: Low		 L18

Connect oscilloscope to TP3 (lead of R81).

Adjsut L18 for maximum reading.

Channel: 40

Mode: AM, RX.

Band: Low

Make sure that clarifier is centered !

 L20

Connect frequency counter to TP3 (lead of R81).

Adjust L20 to obtain 16.7100 MHz reading.

Channel: 40

Mode: USB, RX

Band: Low

 L21 Adjust L21 to obtain 16.7125 MHz reading.

Channel: 40

Mode: LSB, RX

Band: Low

 L22 Adjust L22 to obtain 16.7075 MHz reading.

Channel: 40

Mode: LSB, TX

Band: Low

 VR6 Adjust VR6 to obtain 16.7075 MHz reading.

Channel: 40

Mode: LSB, RX.

Band: Low

 L25

Connect frequency counter to TP5 (lead of R53).

Adjust L25 to obtain 10.6975 MHz reading.

Channel: 40

Mode: USB, RX.

Band: Low

 L24 Adjust L24 to obtain 10.6925 MHz reading.

Channel: 40

Mode: AM, TX.

Band: Low

 L23

Connect frequency counter to TP9 (lead of R84).

Adjust L23 to obtain 10.6950 MHz reading.

 

Alignment of Transmitter:

 

Preset to: Adjustment: Comments:

Channel: 40

Mode: USB, TX.

Band: Low

 VR10

Connect DC Ammeter to TP8(+) and TP7 (-).

Disconnect the PC-834 jumper PCB.

Adjsut VR10 to obtain a 8mA current reading.

Channel: 40

Mode: USB, TX.

Band: Low

 VR9

Connect DC Ammeter to TP8(+) and TP6 (-).

Adjsut VR9 to obtain a 100mA current reading.

Channel: 40

Mode: USB, TX.

Band: Low

Audio generator set to 30mV, 500Hz and 2400Hz two tone signal.

 L43 and L44

Disconnect the DC Ammeter, re-instal the PC834 jumper PCB.

Connect power meter, and oscilloscope to antenna socket (don't forget the dummy load).

Set VR7 clockwise to maximum.

Adjust L43 and L44 for peak output.

Channel: 30

Mode: USB, TX.

Band: Low

Audio generator set to 30mV, 500Hz and 2400Hz two tone signal.

 L42

Turn the core of L41 to be flat with upper side of the coils cover.

Adjust L42 for maximum output.

Channel: 30

Mode: USB, TX.

Band: High

Audio generator set to 30mV, 500Hz and 2400Hz two tone signal.

 L41 Adjust L41 for the maximum output, keep output below 20V by adjusting audio generator level.

Channel: 1-40

Mode: USB, TX.

Band: Low-High

Audio generator set to 30mV, 500Hz and 2400Hz two tone signal.

 L42 Adjust L42 to obtain minimum power difference between Channel 1 Low band and Channel 40 high band.

Channel: 40

Mode: AM, TX

Band: Low

90% modulation (1kHz tone)

 L30 Adjust L30 to obtain the maximum signal level on oscilloscope.

Channel: 40

Mode: USB, TX.

Band: Low

Audio generator set to 30mV, 500Hz and 2400Hz two tone signal.

 VR7

Adjust VR7 to obtain a reading of 24.5 Volts on oscilloscope.

Channel: 40

Mode: USB, TX.

Band: Low

No modulation

 VR4 Adjust VR4 to obtain the minimum carrier leakage.

Channel: 40

Mode: LSB, TX.

Band: Low

 VR4

As above.

Channel: 40

Mode: AM, TX.

Band: Low

no modulation

 VR11 Adjust VR11 to obtain RF carrier power of 4.0 W on RF power meter.

Channel: 40

Mode: AM, TX.

Band: Low

no modulation

 VR8 Adjust VR8 to obtain an indication of 4 W on radios power meter.

Channel: 40

Mode: AM, TX.

Band: Low

Audio generator set to 30mV 1kHz modulation

 VR5 Adjsut VR5 to obtain 90% modulation.

Channel: 40

Mode: FM, TX.

Band: Low

Audio generator set to 30mV 1kHz modulation

 VR3

Connect deviation meter.

Adjust VR3 to obtain 4.5kHz deviation on meter.

 

 

Alignment of Receiver:

 

Preset to: Adjustment: Comments:

Channel: 40

Mode: AM, RX.

Band: Low

NB/ANL: Off

RF gain: Maximum

Volume: Maximum

Squelch: Off

  

Connect RF signal generator to radio, set to 27.405 MHz with 30%, 1 kHz modulation.

Connect oscilloscope and 8 ohm dummy load to external speaker jack, set scope up for audio frequency measurement.

  L7 Turn core of L7 clockwise fully to end of adjustment.
  L6, L8, L10, L11, L12, L13, L14

Adjust to obtain the maximum output audio output power on oscilloscope.

Keep output below 500mW by reducing RF generator level.
  L7 Adjust L7 to obtain the maximum audio output power.

Channel: 39

Mode: AM, RX.

Band: Low

NB/ANL: ON

Squelch: Off

 L1, L2

Connect oscilloscope to TP1, adjust RF signal generator to channel 39 with no modulation and activate 20dB attenuator.

Adjust L1 and L2 to obtain the maximum DC voltage on oscilloscope.

Channel: 40

Mode: AM, RX.

Band: Low

NB/ANL: ON

Squelch: Maximum

 VR2

Set RF signal generator to channel 40, 30%, 1 kHz modulation.

Adjust VR2 to turn off the squelch circuit when RF generator output reaches 1000uV.
  VR1

Set the RF signal generator output to 100uV, no modulation.

Adjust VR1 to obtain a reading of "S-9" on radios signal meter.

Channel: 40

Mode: FM, RX.

Band: Low

 L3, L4

Set the RF signal generator output to 5uV no modulation.

Connect oscilloscope to TP10 (lead of R279).

Adjust coils to obtain maximum indication on oscilloscope.
  L5

Set the RF signal generator output to FM 1.5kHz deviation, 1mV.

Adjust L5 to obtain maximum reading on oscilloscope.

 

 

List of adjustments:

 

VR1 Signal meter
VR2 Squelch
VR3 FM Deviation (modulation)
VR4 Carrier Balance
VR6 TX Frequency
VR7 ALC
VR8 RF power meter
VR9 Final Bias
VR10 Driver Bias
VR11 TX Power
L1 Noise blanker
L2 Noise blanker
L3 I.F. 1st stage
L4 I.F. 2nd stage
L5 FM sense
L6 RX (1st stage)
L7 RX (2nd stage)
L8 RX (3rd stage)
L9 RX (4th stage)
L10 RX (5th stage)
L11 RX (6th stage)
L12 RX (7th stage)
L13 RX (8th stage)
L14 RX (9th stage)
L16 Loop mixer
L17 VCO
L18 VCO output
L20 AM loop frequency
L21 USB loop frequency
L22 LSB loop frequency
L23 AM offset frequency
L24 USB offset frequency
L25 LSB offset frequency
L43 TX mixer input
L44 TX mixer input
L42 TX mixer output (1st stage)
L41 TX (2nd stage)
L30 TX

 

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