LUDLUM MODEL 177
ALARM RATEMETER
October 2018
Serial Number 322945 and Succeeding
Serial Numbers
Page 1: ...LUDLUM MODEL 177 ALARM RATEMETER October 2018 Serial Number 322945 and Succeeding Serial Numbers ...
Page 2: ...LUDLUM MODEL 177 ALARM RATEMETER October 2018 Serial Number 322945 and Succeeding Serial Numbers ...
Page 3: ... implied warranty of merchantability or fitness which extend beyond the description of the face there of If the product does not perform as warranted herein purchaser s sole remedy shall be repair or replacement at the option of Ludlum Measurements In no event will Ludlum Measurements be liable for damages lost revenue lost wages or any other incidental or consequential damages arising from the pu...
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Page 6: ...rhaul Only 4 4 Safety Considerations 5 Environmental Conditions for Normal Use 5 1 Cleaning Instructions and Precautions 5 1 Warning Markings and Symbols 5 2 Electrical Safety Precautions 5 2 Calibration and Maintenance 6 Calibration 6 1 Establishing an Operating Point 6 2 Maintenance 6 3 Troubleshooting 7 Troubleshooting Electronics that Utilize a GM or Scintillation Detector 7 1 Troubleshooting ...
Page 7: ... 8 2 High Voltage HV 8 3 Low Voltage 8 3 Battery Charge 8 3 High Voltage Test 8 3 Alarm Set Voltage 8 3 Battery Test Voltage 8 4 Recycling 9 Parts List 10 Model 177 Alarm Ratemeter 10 1 Main Board Drawing 347 496 10 1 Calibration Board Drawing 347 132 10 4 Wiring Diagram Drawing 347 492 10 5 Drawings and Diagrams 11 ...
Page 8: ...PM on the standard meter dial others are available Detector high voltage is adjustable from 400 to 1500 volts The unit incorporates an adjustable alarm set point The alarm setting may be checked by depressing the front panel TEST switch Audible and visual enunciators are triggered when the meter reading rises above the alarm set point Accessory outputs include Unbuffered Output Supply Voltage Nega...
Page 9: ...177 serial number is located on the back panel of the instrument To return an instrument for repair or calibration provide sufficient packing material to prevent damage during shipment Every returned instrument must be accompanied by an Instrument Return Form which can be downloaded from the Ludlum website at www ludlums com Find the form by clicking the Support tab and selecting Repair and Calibr...
Page 10: ...m a check source or calibrated source if available Remove the source Set the instrument to the appropriate range with the RANGE selector switch If the alarm point is not already set press the ALARM TEST switch and adjust ALARM SET for the desired alarm point Note The meter displays the alarm set point when the ALARM TEST switch is depressed Recheck the set point after locking the ALARM SET control...
Page 11: ...ale reading when measured with an electronic pulse generator Battery Dependence Meter readings vary less than 3 within battery check limits High Voltage variable from 400 to 1500 V Input Sensitivity adjustable from 10 through 100 mV Connector Series C Audio unimorph speaker with volume control located on the front panel Meter 1 mA size 6 4 x 6 4 cm 2 5 x 2 5 in DC movement Meter Scale 0 500 CPM 0 ...
Page 12: ...f full scale Alarm Output visual indicator lamp audible tone and remote current sink Alarm Control factory set to latching non latching alarm available through the removal of main board resistor R116 Finish powder coat paint Size 12 7 x 20 3 x 15 2 cm 5 x 8 x 6 in H x W x D excluding handle Weight 1 9 kg 4 2 lb with battery ...
Page 13: ...is control has minimal effect on the audio when the alarm is activated Audio Speaker a unimorph speaker located behind the front panel ALARM Lamp a red lamp that comes on when the alarm threshold has been exceeded The lamp will remain on unless the alarm is configured to non latching until the reset button is depressed driving the meter needle below the alarm threshold RANGE Selector Switch a four...
Page 14: ...nt the SLOW position should be used BAT TEST Button When this button is depressed the meter displays the battery status A sufficiently charged battery is indicated when the meter needle is on or within the BAT TEST range HV TEST Button When this button is depressed the meter displays the detector high voltage ALARM TEST Button When this button is depressed the meter displays the alarm calibration ...
Page 15: ...tely 3 3 microamperes to zero the meter PIN 7 Recorder output adjustable from 0 to 1 0 volts at 1 milliamperes PIN 8 and PIN 9 Spares CAL Control Remove the calibration cal cover plate to access the following calibration potentiometers DISCR Discrimination Control For pancake type GM detectors i e Model 44 9 adjust DISCR for 80 10 millivolts All other GM detectors and scintillators should be set t...
Page 16: ...Only The following controls are located internally on the main circuit board BAT C used to adjust charge voltage to 6 825 volts BAT T used to adjust meter test voltage reading to 5 97 volts at the BAT OK line HV T used to adjust the high voltage test reading to correspond with the actual high voltage output ...
Page 17: ...Vac Installation Category II Overvoltage Category as defined by IEC 1010 1 Pollution Degree 2 as defined by IEC 664 Normally only nonconductive pollution occurs Temporary conductivity caused by condensation is to be expected Cleaning Instructions and Precautions The Model 177 Alarm Ratemeter may be cleaned externally with a damp cloth using only water as the wetting agent Do not immerse the instru...
Page 18: ...rong power converter is used the instrument and or power converter could be damaged Electrical Safety Precautions Warning Failure to comply with the following instructions could result in a hazardous situation which if mishandled could result in death or serious personal injury When installing the unit Do not expose the unit to rain or an environment where it may be splashed by water or other liqu...
Page 19: ...ccessing the internal components This symbol appears on the front panel Note the following precautions Warning The operator is strongly cautioned to take the following precautions to avoid contact with internal hazardous live parts that are accessible using a tool 1 Turn the instrument power OFF and disconnect the power cord 2 Allow the instrument to sit for one minute before accessing internal co...
Page 20: ...t DISCR for 80 10 millivolts All other GM detectors and scintillators should be set to 35 10 millivolts To lower the scintillation detector operating voltage decrease the input sensitivity to 10 2 millivolts Adjustment is made by setting the pulse generator amplitude to the desired pulse height Adjust DISCR until the meter reaches 75 of the generated incoming count rate Connect the Model 177 to an...
Page 21: ...n or the high voltage Voltage affects the output of the detector Amplifier gain is controlled by the DIS discriminator control In special cases of GM detectors a minimum voltage must be applied to establish the Geiger Mueller characteristic Further changes in gain will not affect this type of detector The operating point for each detector is set at a compromise point between sensitivity stability ...
Page 22: ...ve precedence over this recommendation To maintain the life of the battery it is recommended that the instrument be constantly connected to external power with the power switch in the ON position even when the instrument is not in use This will keep the internal battery fully charged When the instrument is used without external power adequate charge time must be allowed for the internal battery to...
Page 23: ...or cables and sticky meters Note that the first troubleshooting tip is for determining whether the problem is with the electronics or with the detector A Ludlum Model 500 Pulser is invaluable at this point because of its ability to simultaneously check high voltage input sensitivity or threshold and the electronics for proper counting We hope these tips will prove to be helpful As always please ca...
Page 24: ...e the cable and observe the reading for significant changes 3 Check for sticky meter movement Does the reading change when you tap the meter Does the meter needle stick at any spot 4 Check the meter zero Turn the power OFF The meter should come to rest on 0 Meter goes full scale or pegs out 1 Replace the detector cable to see if it has failed causing excess noise 2 Check the HV and if possible the...
Page 25: ...light leak is determined changing the aluminized polyester window assembly will usually fix the problem Note When replacing the window make sure to use a window made with the same thickness of aluminized polyester and the same number of layers as the original window 2 Verify that the HV and input sensitivity are correct Alpha and gamma scintillators typically operate from 10 35 mV High voltage var...
Page 26: ...f the current from the current mirror Positive pulses from Pin 7 of U121 are coupled to the discriminator Discriminator Comparator U021 provides discrimination The discriminator is set by the DIS Discriminator control located on the rear panel coupled to Pin 5 of U021 Negative pulses approximately 5 volts at Pin 7 of U021 are coupled to Pin 5 of U011 for meter drive and Pin 11 of U011 for audio Di...
Page 27: ... bias of Pin 2 the output at Pin 1 goes high Q102 and Q103 saturate allowing supply voltage to be coupled to Lamp voltage through R004 Audio oscillator U16 through CR112 R116 couples back to base of Q102 locking up the Alarm On Through CR113 to audio transformer T211 allowing full voltage for full volume Through R111 to saturating current sink Q101 for external use Reset Reset is provided by coupl...
Page 28: ... 2 U311 With the HV control wiper at ground high voltage output is maximum Low Voltage Low voltage is supplied by internal battery B1 wiring diagram 347 126 or external power T1 Unregulated power at C125 is coupled to voltage regulator VR211 and battery charger U201 Q301 Regulated low voltage is supplied to the balance of the circuit through VR131 at 5 0 volts and U301 at 1 2 volts Battery Charge ...
Page 29: ...alManual Section8 Ludlum Measurements Inc Page 8 4 October 2018 Battery Test Voltage Battery test voltage is controlled by R002 through BAT TEST switch ALARM TEST switch then voltage follower Pin 5 of U311 to the meter ...
Page 30: ...ut simply desires to inform its consumers of the range of recyclable materials present in its products so that the user will have flexibility in following all local and federal laws The following types of recyclable materials are present in Ludlum Measurements Inc electronics products and should be recycled separately The list is not all inclusive nor does it suggest that all materials are present...
Page 31: ...5663 C022 0 001µF 100V 04 5659 C023 C024 0 1µF 50V 04 5663 C025 10PF 100V 04 5673 C101 22µF 20V 04 5672 C111 0 022µF 50V 04 5667 C112 470PF 100V 04 5668 C121 0 001µF 100V 04 5659 C122 2 2µF 20V 04 5671 C123 1µF 35V 04 5656 C124 100PF 3KV 04 5532 C125 3300µF 35V 04 5675 C211 47µF 10V 04 5666 C221 0 0056µF 3KV 04 5522 C301 C302 47µF 10V 04 5666 C311 C312 0 01µF 50V 04 5664 C321 100PF 3KV 04 5532 C32...
Page 32: ... 05 5841 Q401 MJD210 05 5843 VR211 LM2931AT 5 0 05 5813 U011 CD74HC4538M96 06 6297 U012 HFA3096BZ96 06 6468 U021 TLC372IDR 06 6290 U111 ICM7555CBA 06 6300 U121 HFA3096BZ96 06 6468 U201 ICL7663SCBA 06 6302 U301 LM285DR 1 2 05 5845 U311 TLC27M7IDR 06 6292 CR111 CR114 MMBD914LT1G 07 6353 CR201 CR202 CXSH 4LF 07 6358 CR321 1N4007 07 6274 CR401 MMBD914LT1G 07 6353 CR421 CR423 1N4007 07 6274 RT314 250K ...
Page 33: ...871 R1 10 0K 1 250mW 12 7839 R101 1 00K 1 250mW 12 7832 R102 10 0K 1 250mW 12 7839 R103 100 ohm 1 250mW 12 7840 R111 1 00K 1 250mW 12 7832 R112 100K 1 250mW 12 7834 R113 1 00M 1 250mW 12 7844 R114 35 7K 1 250mW 12 7911 R115 100 ohm 1 250mW 12 7840 R116 56 2K 1 250mW 12 7873 R117 1 00M 1 250mW 12 7844 R118 3 32K 1 250mW 12 7870 R121 3 92K 1 250mW 12 7875 R122 10 0K 1 250mW 12 7839 R123 100 1 250mW ...
Page 34: ...5 1W 12 7738 T211 4275 083 4275 083 T411 40 0902 9 GND 10 GND 40 0902 P1 640445 3 MTA 156x3 13 8125 P2 1 640456 2 MTA 100x12 13 8061 P3 1 640456 0 MTA 100x10 13 8066 10 EA CLOVERLEAF RECEPT 011 6809 000 599 18 8771 1 EA 26 Black Coax Ground 2 5 inch 21 9432 BOARD Completely Assembled Calibration Board 5347 189 C1 0 0047µF 100V 04 5570 C2 0 047µF 100V 04 5565 R1 10K RECORDER 09 6787 R2 100K HV 09 6...
Page 35: ... 09 6753 R2 100K ALARM SET 09 6795 J1 MAIN BOARD 5347 496 3 PIN SIP CONN 640428 3 MTA 156 13 8124 J2 MAIN BOARD 5347 496 12 PIN SIP CONN 1 640441 2 13 8431 J3 MAIN BOARD 5347 496 10 PIN SIP CONN 1 640441 0MTA 100 13 8197 J4 CONNECT BOARD 5347 489 13 7801 5 PIN SIP CONN 3 640428 5 MTA 156 J5 CONNECTOR BOARD 5347 489 13 8096 2 PIN SIP CONN3 643193 2 MTA 156 J6 CALIBRATION BOARD 13 8161 5347 189 11 P...
Page 36: ...1 8 MTA 100 Reference Description Part Number DS2 UNIMORPH TEC3526PU 21 9251 B1 6V PS610 GELL CELL 21 9385 F1 1 AMP FUSE 312001 AGC 1 21 9704 DS1 LAMP PT 502 OUR 002F W6 21 9169 DS3 LAMP PT 502 OUR 002F W6 21 9169 M1 Model 177 METER 4173 166 KNOB PKG 50B 08 6601 KNOB 407D2KI 08 6604 KNOB LOCK KL 701 08 6607 KNOB 70 1 2G 08 6637 WALL TRANSFORMER 21 8887 PX9025AWPL05 9 VDC 2 5A AUDIO BATTERY MISCELL...
Page 37: ... MAIN BOARD Drawing 347 496 4 sheets MAIN BOARD Component Layout Drawing 347 503 CALIBRATION BOARD Drawing 347 132 CALIBRATION BOARD Component Layout Drawing 347 133 CONNECTOR BOARD Drawing 347 x 489 CONNECTOR BOARD Component Layout Drawing 347 x 490 WIRING DIAGRAM Drawing 347 492 Section 11 ...
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