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6.  TROUBLESHOOTING  page

 

25

 

 

Model PRM-470B 

6.2.  TROUBLESHOOTING GUIDE 

 

This guide is designed so that repairs can be made to the PRM by qualified service personnel and 

the instrument returned to service within a minimum time.  It emphasizes board and assembly 

replacement. 

 

General problems include inoperable switches, batteries that fail to charge, failed audio, broken 

wires, etc.  Intermittent problems are often caused by loose or broken wires or loose connections. 

 

Perform a physical inspection of the instrument, looking for faulty or broken wiring, foreign 

material, broken or damaged components, and loose connections. 

 

Refer to the appropriate drawings (Appendix F.) for location of components as they are noted 

while using these procedures. 

 

The following tools and equipment are needed for these procedures: 

 

•  Phillips screwdriver 

 

•  Slotted screwdriver 

 

•  Oscilloscope 

 

•  High voltage probe (>1,000 megohms) 

 

•  Nut-driver set 

 

•  DVM 

 

Содержание PRM-470B

Страница 1: ...PORTAL RADIATION MONITOR MODEL PRM 470B OPERATING AND SERVICE MANUAL Version 1 01z December 20 2004...

Страница 2: ...SETUP CHECKLIST 9 3 OPERATING INSTRUCTIONS 10 3 1 POWER UP AND SELF TEST 10 3 2 SEARCH MODE 11 3 3 BACKGROUND MODE 11 3 4 MODE CHANGE AND RESET 12 3 5 DISPLAY BACKLIGHT 12 3 6 LOW BATTERY DETECT 12 3...

Страница 3: ...25 6 3 PRCB 001 BOARD 28 APPENDIX 29 A WARRANTY 29 B GLOSSARY 30 C FORMULAS 32 C 1 ACTIVITY FROM COUNTS 32 C 2 EFFICIENCY 32 C 3 N SIGMA ALARM LEVEL 32 C 4 RELIABLE DETECTABLE ACTIVITY RDA FORMULA 33...

Страница 4: ...gamma and neutron sensitive A display backlight is supplied to permit use in low light conditions Uses for the PRM include Special Nuclear Material SNM searches at plant exits and material access are...

Страница 5: ...radiation intensity Two rotary switches control sensitivity while in the search mode The switches are located on the PRCB 474 PC board inside the instrument The range of the sensitivity adjustment is...

Страница 6: ...es 400 volts ac for operation and care must be taken to avoid accidental contact while servicing the instrument CAUTIONS The PRM 470B is water resistant but will not withstand immersion in water The i...

Страница 7: ...and LED Count Time Search mode 0 05 sec count with 4 sec moving average Background time 10 sec Display LCD one line x 4 characters with backlight Power The internal NiCad battery pack provides more th...

Страница 8: ...1 INTRODUCTION page 5 Model PRM 470B Dimensions 8 h x 5 w x 3 d 20 x 12 5 x 7 5cm Weight 2 4 lb 1 1kg with batteries Environmental Temperature 32 to 100 F 0 to 38 C Humidity Up to 95 non condensing...

Страница 9: ...evidence of concealed as well as external damage 2 1 2 Damage Claims If the instrument is damaged in transit or fails to meet specifications upon receipt notify the carrier and TSA Systems immediately...

Страница 10: ...pection charge the battery for several hours Although the battery is fully charged before the instrument leaves the factory some discharge is possible if the instrument has been in storage for any len...

Страница 11: ...s setting is multiplied by 100 so a setting of 19 would result in 1900 cps per sievert NOTE Setting both k factor switches to 0 will display cps The settings will appear on the display for approximate...

Страница 12: ...____ Background in operating area _____________________________ ____ Mode change operates correctly ____ Sonalert works properly ____ Alarm test source used __________________________________ ____ Se...

Страница 13: ...ay test with all segments and decimal points ON for 2 seconds accompanied by the audible alarm The instrument will then display the current settings for 3 seconds each If any of the power up tests fai...

Страница 14: ...ween X1 2 and X1 3 When the motion switch is enabled each time the instrument is moved a 15 second timer is activated The instrument will stay in search mode until the 15 second timer expires The inst...

Страница 15: ...automatically at power up The display backlight will turn off again when the instrument enters the initial background countdown After the countdown starts and at any other time while the instrument i...

Страница 16: ...ent is operating will have no effect 3 8 TYPICAL SEARCH PROCEDURES The following search techniques are drawn from examples given in the Los Alamos National Laboratories User s Manual Hand Held Search...

Страница 17: ...artments hood trunk and glove box should be opened and scanned with particular attention paid to possible areas of concealment such as wheel wells hub caps and relatively inaccessible areas If contami...

Страница 18: ...rd PRCB 001 Refer to PCRB 001 Control Board Schematic Diagram Drawing 4 and PCRB 001 Control Board Component Designator Drawing 5 Appendix F The PRCB 001 microprocessor control board is the computer b...

Страница 19: ...voltage divider resistors and capacitors It divides the incoming high voltage for the dynodes in the PMT and decouples the signal from the high voltage 4 1 5 Batteries and Battery Charger The instrum...

Страница 20: ...ing the mode switch until it is acknowledged with a beep The display will flash in background mode while the instrument constantly updates the background count to reflect changes in the environment Th...

Страница 21: ...old since the display is updated every second while the alarm comparisons are made every 50 milliseconds 4 5 AUDIO ALARM The audio alarm is a piezoelectric type It is activated to signal the start of...

Страница 22: ...CTRONIC CALIBRATION PROCEDURE The following is a list of the equipment required for the electronic calibration procedure These steps should only be performed by qualified service personnel Oscilloscop...

Страница 23: ...ustment Refer to PCRB 001 Control Board Schematic Diagram Drawing 4 and PCRB 001 Control Board Component Designator Drawing5 Appendix F Connect a digital volt meter between TP2 and ground Adjust R18 t...

Страница 24: ..._____________ Background obtained ___________________________________________________________ ___ Calibration procedure performed Source used __________________________________________________________...

Страница 25: ...procedures 6 1 1 PRCB 001 Board Refer to PCRB 001 Control Board Schematic Diagram Drawing 4 and PCRB 001 Control board Component Designator Drawing 5 Appendix F The PRCB 001 board is mounted on stand...

Страница 26: ...wire is soldered onto the copper layer and connected to the Molex connector The shield can be easily separated from the board Disconnect the Molex connectors from either end of the board The board can...

Страница 27: ...1 4 Detector Assembly The detector assembly is made up of the PMT and the organic plastic detector In either case it is considered to be one unit and must be replaced as such The detector is visible...

Страница 28: ...udio broken wires etc Intermittent problems are often caused by loose or broken wires or loose connections Perform a physical inspection of the instrument looking for faulty or broken wiring foreign m...

Страница 29: ...ally 6 2 2 High Voltage If the problem persists with proper dc voltage present check the high voltage board by connecting the high voltage probe to J2 1 on the HHV 454 board The ground end of the prob...

Страница 30: ...libration Procedure section 5 2 If any of the steps fail then the computer board must be replaced 6 2 5 Switches To test the front panel switches remove the PRCB 001 board and test the switches using...

Страница 31: ...arts section Appendix E 1 for information on parts ordering and replacement of the PRCB 001 board assembly Test points TP1 VCC test point This should be 5 0 0 25Vdc TP2 Ground TP3 Counter input This i...

Страница 32: ...f the manufacturer s liability to TSA TSA reserves the right to modify the design of its product without incurring responsibility for modification of previously manufactured units Since installation c...

Страница 33: ...ing Diode LLD The Lower Level Discriminator provides a threshold usually adjustable that determines the lowest signal level that will be accepted as a nuclear pulse by the system s electronics Some sy...

Страница 34: ...s filled the background is updated This results in a background update at background time 10 Initial background accumulation requires the full background time Standard Background Standard background r...

Страница 35: ...s operate C 1 ACTIVITY FROM COUNTS Activity Activity in nCi Eff Decimal efficiency i e 10 0 1 Where N Net counts per second cps background cps C 2 EFFICIENCY N cps with source background cps Where act...

Страница 36: ...percent F false alarm level in cps FA false alarm sigma G intermediate variance RDA reliable detectable activity in DPM C 5 SIGNAL TO BACKGROUND RATIO The following formula is helpful is determining...

Страница 37: ...ks in the detectors and periodic noise in the electronics Periodic noise will result in a number of about 1 a light leak will usually result in a number larger than 2 The number displayed during a var...

Страница 38: ..._____________ INSTALLED BY ________________________________ DATE ______________ MODIFICATION ______________________________________________________________ ____________________________________________...

Страница 39: ...background is not needed to perform the repairs Three these spare parts are supporting from one to five systems NOTE If there are more than five systems one set of spare parts should be maintained per...

Страница 40: ...umber Part description from parts list When ordering programmed proms the software version is required This can be found on the prom label NOTE Model number suffixes are generally not included in the...

Страница 41: ...PRM 470B Internal 3D View 2 PRM 470B Wiring Diagram 3 PRCB 001 Control Board Schematic Diagram 4 PRCB 001 Control Board Component Designator 5 HHV 454 High Voltage Power Supply Schematic Diagram 6 HHV...

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