Galaxy DX 2547 AM/SSB CB Base Station Radio Service Manual Excerpts

Support, support, support…The Galaxy support department was gracious enough to send the Galaxy Noise Filter schematic with out a request! This is what is missing in most instances these days with large consumer electronics companies. Their either to big to follow up on details, don’t know were to get the information, or plain don’t care. Another reason for the lack of support for many radios is that the radios are designed, built and documented off shore and shipped directly to the distributor.

The distributor doesn’t understand radio technology nor do they understand end user customer support. All they see is the chance to make higher profits by cutting out the important link between the factory over seas and themselves. Most of these radios end up in yard sales or the trash soon after the purchase. Sure you can save a few bucks, but what do you do when the thing quits or there is a technical design flaw.

Who’s out their to follow up on it. Don’t think the distributor or mail order company will. They’ll drop it like a hot rock and find a new product to make profit on. Not at Galaxy, they support their product 100% and beyond. To be honest there are a few companies that support their products, but increasingly I see more products that are not supported at all. Have you ever tried to get a service manual for the Uniden Washington base radio? They haven’t supplied them for many years! Need more be said?

Click On Picture For Close-up.

Galaxy Noise Filter Schematic

Galaxy Noise Filter Schematic.

 

Galaxy Microphone Wiring Diagram.Galaxy DX 2547 Mic Jack Pin Assignments.
Figure 2-3 Your Transceiver Microphone Schematic.Figure 2-4 Microphone plug and pin numbers viewed from rear of pin receptacle.

The following information is from the Galaxy DX 2547 Service Manual supplied with the radio.

 

Figure 4-1, Transmitter Test Setup
Galaxy Transmitter Test Setup Diagram.
Figure 4-2, Receiver Test Setup
Galaxy Receiver Test Setup Diagram.

 

REQUIRED TEST EQUIPMENT
  1. DC Power Supply (13.8VDC, 10A)
  2. RF Wattmeter (100 MHz, SOW)
  3. Multimeter (Digital)
  4. Automatic Modulation Meter
  5. Audio Signal Generator
  1. Frequency Counter (100 MHz)
  2. RF Signal Generator (100 MHz)
  3. Automatic Distortion Meter
  4. Oscilloscope (50 MHz)
  5. Sinad Meter

ALIGNMENT PROCEDURES 

This transceiver has been aligned at the factory and does not require any adjustments at installation. The required test equipment listed is used for the test setup or alignment shown in Figure 4-1 Transmitter Test Setup and Figure 4-2 Receiver Test Setup. This test setup is used in part or total during the following adjustments. Refer to Page 43 for adjustment location.

PLL ALIGNMENT
ITEMU.U.T. (UNIT UNDER TEST) SETTINGADJUSTPOINTMEASUREMENT
RegulatorVoltageConnect Voltmeter positive lead to power switch.Connect Voltmeter negative lead to PCB ground.VR70113.8 VDC
VCODisconnect ‘short PCB’ from TP7, TP8 and TP9.Set radio to CH 1 AM RX mode.Connect Voltmeter to TP2.L142.5 VDC t 0.1
Set CLARIFIER Control to 12 o’clock.Connect Oscilloscope to TP3.L15Adjust for max.
Connect Frequency Counter to IC3 Pin 8VC110.2400MHz t 20Hz
 AM FrequencySet radio to CH 1 AM RX mode.Connect Frequency Counter to TP3.L2016.2700MHz t 20Hz
USB FrequencySet radio to CH 1 USB RX mode.Connect Frequency Counter to TP3.L2116.2725MHz ± 20Hz
LSB FrequencySet radio to CH 1 LSB RX mode.Connect Frequency Counter to TP3.L2216.2675MHz ± 20Hz
TX OffsetFrequencySet radio to CH 1 AM TX mode.Connect Frequency Counter to TP3.VR716.2675MHz t 20Hz
AM OSCSet radio to CH 1 AM TX mode.Connect Frequency Counter to TP5.L2310.695OMHz ± 10Hz
USB OSCSet radio to CH 1 USB TX mode.Connect Frequency Counter to TP6.L2410.6925MHz t 10Hz
LSB OSCSet radio to CH 1 LSB TX mode.Connect Frequency Counter to TP6.L2510.6975MHz:t 10Hz
TRANSMITTER ALIGNMENT
BIAS CurrentSet radio to CH 19 USB TX mode.Modulation Off.Connect current meter to TP7(+) and TP9Connect current meter to TP7 (+) and TP8VR12VR1050 mA100 mA
SSB APCSet radio to CH 19 USB RX mode.Connect Multimeter to TP7.VRI712.5 VDC
SSB TX PowerConnect “short PCB” to TP7, TP8 andConnect RF Power Meter to antenna jack.Set radio to CH 19 USB TX mode.AF signal 30mV, 1 KHz to microphone.Set RF PWR Fully Clockwise.Set MIC GAIN Fully Clockwise.L40,L42,L43,L44MAX > 12WSpurious EmissionMinimum.Balance PowerBetween CH1 andCH4O.
SSB ALCSet radio to CH 19 USB TX mode.AF signal 3OmV, I KHz to microphoneVRI311.5 W
SSB CarrierBalanceSet radio to CH 19 USB TX mode.Set MIC GAIN Fully Counter Clockwise.Connect Oscilloscope to antenna connector.VR6Spurious Emission toMinimum.
AM TXHigh PowerSet radio to CH 19 AM TX mode.Modulation Off.VR143.8 W
AM TXLow PowerSet RF POWER fully counterclockwise.VR180.5w
RF PowerMeterSet radio to CH 19 AM TX mode.Set RF POWER fully Clockwise.Set SWR/MOD/PWR Switch to PWR positionVR9For a needle readingof “4” on TX PWR scale.
AM ModulationMeterSet radio to CH 19 AM TX mode.AF signal 30mV, 1 KHz to microphone.Set MIC Gain fully Clockwise.Set SWR/MOD/PWR Switch to MOD positionVR16For a needle readingof 95% on theModulation scale.
FrequencyCounter Adjust Set radio to CH 19 AM RX mode Set CLARIFIER Control to 12 o’clock. VC1 onfrequencycounterPCB.Display should be27.1850

RECEIVER ALIGNMENT

AM SensitivitySet radio to CH 19 AM RX mode.Set RF GAIN Fully Clockwise.Set SQ Fully Counter Clockwise.Set VOL Control at 2 o’clock.Set NB/ANL switch to OFF position.Set TONE Fully Clockwise.Set CLARIFIER Control to 12 o’clock.Connect RF SG to antenna jack Frequency 27.185 MHz, lmV. Mod 30%.L2,L3,L5,L6,L7,L8,L9,L10Audio Output > 2VS/N > 10 dB.
Set radio to CH 40 AM RX mode.RF SG setting 27.405 MHz.Set radio to CH 1 AM RX mode.RF SG setting 26.965 MHz.L5,L6For Balance BetweenCH 1 and CH 40
USB SensitivitySet radio to CH19 USB RX modeSet VOL Control Fully Clockwise.RF SG setting 27.186 MHz, 0.5uV. Mod off.L11,L12Audio Output > 2VS/N > lOdB
LSB SensitivitySet radio to CH19 LSB RX modeSet VOL Control Fully Clockwise.RF SG setting 27.184 MHz, 0.5uV. Mod off.L11,L12Audio Output > 2VS/N >lOdB.
NB AdjustSet radio to CH 18 AM RX mode.RF SG setting 27.185 MHz, 1000mV Mod off.Set NB/OFF switch to ON position.Connect Multimeter to TP1 (D2 cathode).L1 DC Voltage to max.(> 2.OV)
AM SquelchSet radio to CH 19 AM RX mode.Set SQ Control Fully Clockwise.RF SG setting 27.185 MHz, 2OmV. Mod 30%.VR4Adjust very slowlyuntil squelch just closes.
SSB SquelchSet radio to CH 19 USB RX mode.Set SQ Control Fully Clockwise.RF SG setting 27.186 MHz, 20 mV. Mod off.VR3Adjust very slowlyuntil squelch justcloses.
AM S-MeterSet radio to CH 19 AM RX mode.RF SG setting 27.185 MHz, 100mV. Mod 30%.VR1 For a reading of “9”on the “S” scale.
SSB S-MeterSet radio to CH 19 USB RX mode.RF SG setting 27.186 MHz, 100mV. Mod off.VR2For a reading of “9”on the “S” scale

 

Main PCB Adjustment Location

The Galaxy service manual has many more diagrams including circuit board layouts, block diagram and schematics. Only a small sample have been included in this issue to give the reader a feel for how good the manual is. The manual is professional in every way and will be an valuable asset to anyone who works on the DX 2547.

I don’t know for a fact, but judging by Galaxy’s past history, much of the manual will probably be available on their site before you know it.

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