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A-1. Introduction

 - 

AMPTEC 620UK 

The AMPTEC 630, 640 and now the AMPTEC 620 Series Failsafe Ohmmeters have   become the standard in the 
Safety  Ohmmeter/Igniter  Circuit  Test  industry.  They  provide  extremely  safe  and  reliable  resistance  testing  of 
explosive or volatile devices.  Safety Approvals from various Safety Boards include, the U.S. Air Force 620A-4 for 
generic use on 

munitions and the 

620UK by an independent European 

Eex 

certifying body for Intrinsic Safety. The United Kingdom Ministry of Defense (UK MOD)  and other versions also 
have approved the 620UK Bonding Ohmmeter. Devices the AMPTEC 620UK Safety Bonding Ohmmeter  may be 
used on include: 

1)

 chassis ground connections on fighter jets in Explosive and Volatile environments, 

2)

 fuses, 

3)

squibs, 

4) 

igniters, 

5) 

explosive bolts, 

6) 

rocket motor squibs, 

7) 

flares  

8) 

EED activated mortars, 

9) 

EED activated 

shells, 

10) 

EED activated rounds and many others . 

 

The 

AMPTEC 620UK is approved by SIRA Test & Certification Limited for an intrinsic safety classification of 
EEx ib IIC T4 in accordance with the ATEX Directive. SIRA Test & Certification Limited   is located in   
Chislehurtst, Kent BR7 5EH  ENGLAND 

A-3

)  

explosive ordnance and 

AMPTEC 

The AMPTEC 620UK Ohmmeter complies with the EU ATEX 

Directive and meets the 

Intrinsic Safety standard Eex-ib-IIc-T4

.  The AMPTEC 620UK Ohmmeter has passed 

EMC testing  in accordance with 

British Defence Standard

 59-41Radiated Emissions and Susceptibility. It is also 

complies with 

British Defence Standards

 66-31 (Environmental Heat, Cold, Altitude, Humidity and Atmospheric 

Stress tests), as well as 

British Defense Standard

   07-85 and 

British Defense Standard 

05-34. The AMPTEC 

620UK Ohmmeter provides a reliable and intrinsically safe means of measuring electrical resistance of aircraft 
chassis  ground  connections,  rocket  motor  squibs,  warhead  squibs  ,  explosive  bridge  wire  and/on    a  variety  of 
devices. Featuring seven resistance ranges and an all metal case with a separate battery compartment, the AMPTEC 
620UK  provides  a  safe  and  easy  method  of  measuring  resistance  in  explosive  and  volatile  atmospheres. 

A-2. Unpacking, and Inspection

Should  the  AMPTEC  shipping  box  appear    damaged  upon  arrival  notify  the  carrier 
immediately.  If the 620UK appears damaged, the carrier's agent should authorize repairs 
before the unit is returned to the factory.   Even if the instrument appears undamaged, it 
may have suffered internal damage in transit that may not be evident. 

R M A

SECTION A  - RECEIVING AND INITIAL INSPECTION

4

The AMPTEC 620UK is a 2-wire ( 4 Wire Version Kelvin now available) failsafe digital ohmmeter which reliably 
uses  very  low  test  currents  for  its  resistance  measure-ment. The  open  circuit  voltage  on  the  main  “Test  Lead” 
connector (Pattern 104,  3 way NSN plug) is also diode protected (voltage clamped) and ideal for use in “volatile” 
environments. The AMPTEC 620UK Explosive Safety Ohmmeter is voltage limited (diode protected) to prevent 
arcing  associated  with  the  use  of  the  meter. The  field  tested  Failsafe  Output  Circuitry  pioneered  by AMPTEC 
RESEARCH   ensures that test current levels do not exceed the specified "failsafe current" even in a worst-case 
component failure situation. To conserve  battery power, the AMPTEC 620UK automatically shuts down, or turns 
itself off after approx. 

2

0 minutes of “inactivity”. The  AMPTEC 620UK does not need to “warm-up”, so the user

 may simply repress the power button to effectively reset the  “auto-shutdown” timer. Should the internal batteries (4
 ea. AA type) reach a low energy   level the “LO BAT” indicator message   will appear on the unit’s display. (

see

 Section 

Summary of Contents for 620UK-4

Page 1: ...4045 800 350 5105 website http www amptec com FAX 512 858 4340 TOLL FREE IN THE USA MAINTENANCE and OPERATION MANUAL V4 4 Wire Kelvin Version Amptec Research Corp 13231 Rooster Springs Rd Austin TX 7...

Page 2: ...ICATIONS Table B 2 Specifications p 7 SECTION C REPLACEMENT AND ACCESSORY ITEMS C 1 Available Accessories and Test Leads p 8 SECTION D OPERATION FUNCTION AND USE D 1 General Use p 9 D 2 Front Panel p...

Page 3: ...Operation E 6 Trouble shooting or Diagnostic Test Procedure for AMPTEC 620UK Ohmmeter Printed Circuit Board p 18 E 6 1 Current Source PCB Diagnostic Routine p 18 E 6 2 DVM PCB Diagnostic Routine p 18...

Page 4: ...able and intrinsically safe means of measuring electrical resistance of aircraft chassis ground connections rocket motor squibs warhead squibs explosive bridge wire and on a variety of devices Featuri...

Page 5: ...h has two separate modes The ON position supplies internal battery isolated Anew set of AA batteriesintheAMPTEC 620UK batterypackisdesignedtolastapproximately1 year dependingupon use Duracell PlusType...

Page 6: ...high Ihigh Vlow and Ilow configuration Proper 4 Wire Kelvin connections automatically eliminate test lead wire length resistance and test lead connection contact resistance offsets which is what the z...

Page 7: ...isplay 20 000 counts 4 digit Liquid Crystal Display LCD with a back light for viewing the 620UK display in dim ambient light conditions Low Battery Indication The 620UK LCD Displays shows LOW BAT Over...

Page 8: ...eterwithalligatorcliptestleadset Option 620UK 290 Alligator Clip Test Lead Set 48 long ideal for connecting to wires some jacks and most exposed posts Option 620UK 401 Handheld Probe Test Lead Set ide...

Page 9: ...panel chassis ground panel jack and pin C of the NATO test lead connector are both chassis ground The AMPTEC 620UK user may use either chassis ground connection as a test lead shield provided the tes...

Page 10: ...ohmmeter is fitted with seven resistance ranges The lowest resistance range 2 0 Ohm provides resistance measurement capability from zero ohms up to the level of i 9999 Ohms Fullscale The AMPTEC 620UK...

Page 11: ...you have a V4 Kelvin version The AMPTEC 620UK Ohmmeter when measuring resistance measures the total of three in series items as shown above The first item is the actual test lead wiring resistance com...

Page 12: ...the leads at the end together For example if they are alligator clip option 620UK 290 or banana jack ends option 620UK 401 connect or short the ends to each other 3 Adjust the ten turn precision poten...

Page 13: ...ies offset resistance end of zeroing description D 3 Photo of AMPTEC 620UK in Carry Case Earth Connection between Case and Ohmmeter is shown The front panel of the AMPTEC 620UK houses the following co...

Page 14: ...y the AMPTEC 620UK Ohmmeter front and rear panels are aluminum shielded and have their individual chassis ground lug connections electrically wired to the units front panel chassis ground front panel...

Page 15: ...equipment are in good working order before attempting to troubleshoot the 620 series igniter tester If you turn on the AMPTEC 620UK display does not come on it may indicate the batteries need replaci...

Page 16: ...some safety ohmmeters i e ALINCO 101 series have a history of faulty service related i e wrong component or electrical current limit fault failures which have had catastrophic and deadly result when c...

Page 17: ...ohm resister you get a 50mV drop which inputs into the DVM PCB and is displayed as 10 000 Ohms The 200 Ohm range outputs a constant 500uA DC current When this current level 500uA is routed across a 1...

Page 18: ...rouble shooting or Diagnostic Test Procedure for AMPTEC 620UK Ohmmeter Printed Circuit Board diagnosis or replacement The following steps will facilitate the proper repair personnel to diagnose whethe...

Page 19: ...surement test leads across a known 10 0 Ohm resistance standard i e 0 005 or better Adjust RV401 so the display is the value of the 10 ohm resistance standard Next short the measurement test leads tog...

Page 20: ...er for filed install new AA batterries or can be optionally fitted with security screws Tamper resistant battery compartment lid screws make it extremely difficult for field personnel to install new b...

Page 21: ...ly Safe Certification 21 Sira 03ATEX2076 620UK Safety Ohmmeter EEx ib C T4 II Battery Holder Cover 4 Each type AA Only fit the following battery type Eveready Silver Seal type R65 or Eveready Ultras P...

Page 22: ...dance with the applicable code of practice IEC 60079 19 If the equipment is likely to come into contact with aggressive substances then it is the responsibility of the user to take suitable precaution...

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