Garmin GNC400 Alignment Procedure
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Garmin GNC400 Alignment Procedure

Garmin GNC400 Alignment Procedure

Comm transceiver
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Approvals
Drawn: BAS
Checked: MDD
Approved: MLR
Project Mgr.: TLJ
Rev.
Date
G
10/26/98
H
10/30/98
J
11/20/98
K
8/11/99
L
5/5/00
M
5/23/00
N
6/7/00
P
5/10/01
Q
08/15/01
R
08/20/01
S
09/25/01
T
11/14/01
GNC400 COMM TRANSCEIVER
ALIGNMENT PROCEDURE
GARMIN Corporation
1200 E. 151st Street
Olathe, KS 66062
005-00051-55 Rev. T
Date
6/4/98
6/5/98
6/5/98
6/5/98
Revisions
Description of Change
Change tuning order of IF transformers, change RF AGC
setting.
Increase TX MOSFET bias to 100mA
Add 25 KHz noise squelch adjustment, change SI
program reference to test page display.
Add instructions for tuning –03 board TCXO.
Change voltage range on VCO alignment. Add
troubleshooting note to TX MOSFET bias setting
Add Q-Dope to L302
Q504 Fix
Eliminate TCXO and RX IF Alignment
Add Digital adjustments for PA and Driver bias, and MIC
gain
Change AF IN LO from 600 TO HI to GND
Change TX MOD adjustment on-05 comm to 80%
Update procedures for 16Watt TX
GNC 400 COMM TRANSCEIVER ALIGNMENT PROCEDURE
CONFIDENTIAL
This drawing and these specifications contained herein
are the property of GARMIN Corporation and may not
be reproduced or used in whole or in part as the basis
for manufacture or sale of products without the written
permission of GARMIN Corporation.
P/N 005-00051-55 REV. T
Apprvd.
9901
9929
10058
11584
13278
13396
13512
15734
16341
16379
16582
16894
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Summary of Contents for Garmin GNC400

  • Page 1 6/4/98 This drawing and these specifications contained herein Checked: MDD 6/5/98 are the property of GARMIN Corporation and may not be reproduced or used in whole or in part as the basis Approved: MLR 6/5/98 for manufacture or sale of products without the written Project Mgr.: TLJ...

  • Page 2: Table Of Contents

    TABLE OF CONTENTS 1. GENERAL...................... 3 2. REFERENCE DOCUMENTS ................. 3 Test Equipment ..........................3 Setup Procedure..........................4 3. COMM TRANSCEIVER ASSEMBLY ALIGNMENT........5 Initial Control Settings ......................... 5 3.1.1 Discrete Adjustment........................ 5 3.1.2 Digital Pots ..........................6 3.1.3 Covers............................. 6 Synthesizer Alignment........................

  • Page 3: General

    2. REFERENCE DOCUMENTS 004-00044-03 Min Prfm Spec, GNC 400 Comm 016-00214-XX Assy Dwg, GNC400 Comm PCB 016-00611-XX Assy Dwg, GNC400 Comm, 16 Watt 320-00099-06 Ca Assy, (B), GNC400 COMM 2.1 Test Equipment The test equipment needed to perform an alignment of a GNC 400 COMM XCVR assembly is as listed below.

  • Page 4: Setup Procedure

    HP8920A/B RF IN/OUT connector. Connect the 320-00099- 06 Ca Assy, (B), GNC400 COMM to the 26-pin high-density connector on the back of the comm (J2) and to the surface mount connector J26 on the top side of the comm.

  • Page 5: Comm Transceiver Assembly Alignment

    Figure 1 3. COMM TRANSCEIVER ASSEMBLY ALIGNMENT This section describes the step-by-step procedure used to perform a GNC400 COMM transceiver assembly alignment. Refer to the GNC 400 COMM XCVR MINIMUM PERFORMANCE SPECIFICATION (MPS) Garmin P/N 004-00044-03 for specifications. The unit should be connected as outlined in section 2.2.

  • Page 6: Digital Pots

    (C300 only on –02 and lower 10 Watt comm boards) Y301 TCXO Trimmer Factory preset (Y301 only on –03 and higher 10 Watt comm boards, and 16 Watt comm boards) L302 VCO Coil Mid - range as Factory preset R558 MIC GAIN Fully CW R530...

  • Page 7: Tcxo Alignment

    3.2.2 TCXO Alignment For –03 and higher 10 Watt comm boards, and 16 Watt comm boards, the integrated circuit TCXO Y301 is pre-aligned by the manufacturer and no adjustment is required. AT NO TIME DURING THE TCXO ADJUSTMENT PROCEDURE SHOULD THE TRANSMITTER BE KEYED.

  • Page 8: Receiver If Alignment

    On the unit display, set the TX CAL field to CALIBRT. If the current reading on the DMM increases more than 50mA, send the unit to troubleshoot. SLOWLY Adjust the PA digital pot value until 28V current is between 200 and 300mA. Make note of the PA digital pot value and turn it back to 00.

  • Page 9: Receiver / Transmitter Digital Pot Adjustments

    3.5 Receiver / Transmitter Digital Pot Adjustments If the comm automated alignment software is to be used, follow the steps in section 3.5.1. If the digital pots are to adjusted manually, skip to section 3.5.2. 3.5.1 Comm Automated Alignment Instructions To perform an automated alignment on the comm board: Click on the icon labeled Align 400.

  • Page 10: Receiver Carrier Squelch Calibration - 25 Khz Mode

    State 4 on Radio Test Set: • RX Mode • RF GEN Freq = 118.000 MHz • RF GEN amplitude = 2.0 uV • AF GEN1 to AM • AM DEPTH = 30% • AF GEN1 FREQ = 1 KHz •...

  • Page 11: Receiver Carrier Squelch Calibration - 8.33 Khz Mode

    3.5.5 Receiver Carrier Squelch Calibration - 8.33 kHz Mode Recall saved State 5 on the HP8920A/B as in section 3.5.4. Change RF GEN amplitude to 3.0 uV. Set the channel spacing field on the display for 8.33 kHz. Decrease SQ 833 on the display until the squelch just opens (audio turns on). Increase the SQ 833 one level 3.5.6 Transmitter Output Power Calibration Recall saved state 6 on HP8920A/B.

  • Page 12: Modulator Adjustment For 16 Watt Comm Boards

    3.5.7.2 Modulator Adjustment for 16 Watt comm boards Recall saved State 7 on the HP8920A/B. State 7 on Radio Test Set: • TX Mode • Automatic Tuning • AF ANL IN to AM DEMOD • DE-EMPHASIS to OFF • DETECTOR to RMS*SQRT2 •...

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