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15 

MAINTENANCE 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

2.

 

Remove the ten screws that hold the case top to the chassis and 
front bezel. 

3.

 

Pull  the  front  bezel  away  from  the  chassis  to  access  the 
calibration adjustments. 

 

VOLTAGE AND V METER ADJUSTMENTS

 

 

1.

 

Connect the multimeter (set to 20 DCV Range) to measure the 
dc  voltage  across  the  power  supply 

(+)  and  (–)

  OUTPUT 

terminals. 

2.

 

Turn on the power supply, and set the front panel 

VOLTAGE

 

control maximum (fully clockwise). 

3.

 

Adjust Trimmer 

VR3

 for a reading of 14.50 ± 0.10 volts on the 

multimeter. 

4.

 

Set  the  power  supply  front  panel 

VOLTAGE

  control  for  a 

reading of 14.00 ± 0.10 volts on the multimeter. 

5.

 

Adjust Trimmer 

VR4

 so that the  meter pointer on the 

V

  meter 

lines up with the 14 volt mark. 

6.

 

Turn off unit power to proceed to the current adjustments. 

 

CURRENT AND A METER ADJUSTMENTS 

 

1.

 

Connect  the  0  to  2  ohm  resistive  load  in  series  with  the 
multimeter  (set  to  20  DCA  Range)  to  measure  the  dc  output 
current  across  the  power  supply 

(+)  and  (–)

  OUTPUT 

terminals. 

2.

 

Turn  on  the  power  supply  and  adjust  the  resistive  load  for  a 
reading of 10.0 ± 0.1 amps on the multimeter. 

 

 
 
 
 

 

Figure 6. Location of Calibration Adjustments, Rear View. 

Summary of Contents for 1686A

Page 1: ...1 INSTRUCTION MANUAL MODEL 1686A 3 to 14 VOLT DC POWER SUPPLY...

Page 2: ...hazard a If the equipment under test is the hot chassis type a serious shock hazard exists unless the equipment is unplugged just turning off the equipment does not remove the hazard or the precaution...

Page 3: ...3 Instruction Manual for MODEL 1686A 3 to 14 VOLT DC POWER SUPPLY 22820 Savi Ranch Parkway Yorba Linda California 92887...

Page 4: ...Power Supply Hook up and Operation 9 Considerations 10 Current Limiting 11 Connecting Two Supplies in Series 11 Connecting Two Supplies in Parallel 11 page MAINTENANCE 14 Fuse Replacement 14 Line Vol...

Page 5: ...y radios such as CB transceivers VHF UHF commercial equipment marine car telephone and 2 meter transceivers The power supply utilizes thermostatically controlled fan cooling for improved heat dissipat...

Page 6: ...voltage Short Circuit METERING Voltmeter Range Accuracy 0 to 20V 7 F S Ammeter Range Accuracy 0 to 20A 7 F S AC Input 115 230 VAC 10 50 60Hz POWER CONSUMPTION 400 W TEMPERATURE RANGE HUMIDITY Operatio...

Page 7: ...eed 2 amperes 10 Line Cord 11 Fuse 12 Fan 1 POWER Switch Turns power supply on and off Power on indicated by pilot lamp above switch 2 Power ON light Lights when power is turned on 3 OVERLOAD Indicato...

Page 8: ...8 CONTROLS AND INDICATORS Figure 1 Front Panel Controls and Indicators Model 1686A Figure 2 Rear Panel...

Page 9: ...Observe all TEST INSTRUMENT SAFETY precautions listed in the front of this manual EQUIPMENT PROTECTION PRECAUTIONS CAUTION The following precautions will help avoid damage to the power supply 1 Avoid...

Page 10: ...nugly to assure low resistance 2 Connect the red OUTPUT terminal of the power supply to the positive polarity input of the equipment being powered 3 Connect the black OUTPUT terminal of the power supp...

Page 11: ...provide a variable 6 to 28 volts output The maximum output current will remain at 12 amps See Fig 4 for the connection scheme The voltage is controlled by both VOLTAGE controls and is equal to the sum...

Page 12: ...12 OPERATING INSTRUCTIONS Figure 4 Connecting Two Power Supplies in Series for a 6 to 28 Volt Output...

Page 13: ...13 OPERATING INSTRUCTIONS Figure 5 Connecting Two Power Supplies in Parallel for 3 to 14 Volt Output at Double Amperage...

Page 14: ...e bottom of the chassis To convert to a different line voltage perform the following procedure 1 Make sure the power cord is unplugged 2 Turn the unit over bottom up and reset the LINE VOLTAGE SELECT...

Page 15: ...14 50 0 10 volts on the multimeter 4 Set the power supply front panel VOLTAGE control for a reading of 14 00 0 10 volts on the multimeter 5 Adjust Trimmer VR4 so that the meter pointer on the V meter...

Page 16: ...tive load for a reading of 15 amps on the unit s A meter scale 8 Adjustable Trimmer VR2 clockwise unit the output voltage read on the multimeter drops by 0 05 to 0 20 V INSTRUMENT REPAIR SERVICE Becau...

Page 17: ...ccount must include payment in the form of a money order or credit card For the most current repair charges please visit www bkprecision com and click on service repair Return all merchandise to B K P...

Page 18: ...nstrument via our website www bkprecision com Exclusions This warranty does not apply in the event of misuse or abuse of the product or as a result of unauthorized alterations or repairs The warranty...

Page 19: ...et is removed for servicing a serious shock hazard exists if the chassis is touched Not only does this present a dangerous shock hazard but damage to test instruments or the equipment under test may r...

Page 20: ...20 B K Precision Corporation 22820 Savi Ranch Parkway Yorba Linda California 92887 www bkprecision com 2014 B K Precision Corporation 481 370 9 001 Printed in China V043014...

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