Marconi Instruments P4428 Technical Manual Download Page 4

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Specification

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SPECIFICATION

1. Camera

The camera has been designed to operate in the hostile conditions
encountered in a fire-fighting environment.

Weight

3.0Kg (camera including muff and harness)

Material

Case - Polycarbonate

Harness - Nylon

Muff

PVC/Nylon flame retardant - felt liner

Visor

Neoprene

Immersion

The camera will withstand driving spray and total
immersion in water.

Case Sealing

A test valve is provided so that sealing tests may
be executed using a vacuum pump.

A vent is also included which releases at an
internal excess pressure of 7 p.s.i.

Electrical

Power

3.7W Nominal

Voltage range

8.7V D.C. input

Battery life

10 size AA alkaline disposable cells - typically 2
hours.

10 size AA Nickel Cadmium rechargeable cells -
typically 1 hour.

(Note: rechargeable cells may need to be fully
cycled a few times to achieve maximum charge
capacity.)

Video

The external video signal is nominally 1 Volt 625
lines 50Hz (CCIR compatible) or 525 lines 60 Hz
75

Ω

termination set at manufacture.

Summary of Contents for P4428

Page 1: ...derstanding that the Company s proprietary rights therein are recognised and that it is solely for the information of the recipient must not be copied either as a whole or in part or disclosed to any third party or used as the basis for the manufacture or sale of apparatus without prior written permission from the Company ...

Page 2: ...ctrical Set Up 33 35 REAR FOLD Section 3 Diagrams Block Diagram 1 Circuit Diagrams and Layouts 1 Scan and Monitor Board Old New 2 6 2 Video Processing Board Old New 7 10 3 Voltage Regulator Board Old New 11 14 Parts Lists Scan and Monitor Board Old New 15 21 Video Processing Board Old New 22 28 Voltage Stabiliser Board Old New 29 31 Voltage Stabiliser Unit Old New 32 Chassis 33 Yoke Assembly 34 Fr...

Page 3: ... 1 P4428 Pyroelectric Vidicon Camera Complete with Voltage Stabiliser Unit ...

Page 4: ...A test valve is provided so that sealing tests may be executed using a vacuum pump A vent is also included which releases at an internal excess pressure of 7 p s i Electrical Power 3 7W Nominal Voltage range 8 7V D C input Battery life 10 size AA alkaline disposable cells typically 2 hours 10 size AA Nickel Cadmium rechargeable cells typically 1 hour Note rechargeable cells may need to be fully cy...

Page 5: ...ting and may be cleaned as necessary with an appropriate soft cloth Focal length 18mm f 0 8 Angle of View 57E Spectral Response 8 to 14µm P8092 pyroelectric vidicon PEVICON manufactured by Marconi Applied Technologies Limited Electromagnetic Compatibility CE The camera and VSU of cameras serial number above 6000 comply with the requirements of EU directive 89 336 EEC ...

Page 6: ...Specification 4 2 Voltage Stabiliser Mechanical Weight 0 5Kg less batteries Material Polycarbonate Electrical Input 9 5 to 15 volts Output 8 7V 400mA D C P4428K Voltage Stabiliser ...

Page 7: ...uirements The equipment requires a 9 3 to 15 volt supply at approximately 0 4 amps A battery cartridge is provided which uses 10 standard AA size 1 5 volt disposable alkaline cells The output from this pack is 15 volts nominal and is regulated to 8 7V and current limited to 700mA by the voltage stabiliser unit At least 1 5 hours operation is possible on each set of batteries For use with external ...

Page 8: ...ated into the front of the camera It is synchronous in rate and phase with the camera scanning beam The images obtained are alternately inverted in polarity They are synchronously re inverted and balanced in the video channel to give continuous positive images Shading correction circuits aid balance between the signals and minimise flicker 4 LINE FLYBACK GAS PEDESTAL The ion pedestal within the tu...

Page 9: ...revious paragraph Monitor the head amplifier output voltage on an oscilloscope and adjust the pedestal control for a forward line scan pedestal of 175mV NB The I G4 BEAM PEDESTAL value can be noted for future reference 6 3 Picture Acquisition An image will normally be obtained with the camera controls undisturbed from the previous tube Set the camera to pan mode Turn the circular blanking control ...

Page 10: ...djustments The following controls are provided horizontal shift RV101 vertical amplitude RV112 vertical shift RV113 7 6 Video Adjustments Set the alignment controls RV102 RV103 scan board for even target illumination and adjust the shading and black level controls video board as covered in the picture acquisition section 6 3 7 7 Circular Blanking To increase the signal out of the tube it is usual ...

Page 11: ... Generator Video Board The sync generator uses a RCA integrated circuit type CD22402 which is locked to its own 500kHz crystal oscillator Conversion from 625 lines 50Hz to 525 lines 60Hz is possible by opening the solder link between pin 18 and 19 of the integrated circuit 8 2 Video Head Amplifier The head amplifier is located on the video board and is a high gain low noise amplifier with a nomina...

Page 12: ...switch also modifies the channel gain and black level by switching transistor Q204 TR6 and resistors R227 R228 and RV200 R34 R35 8 5 Circular Blanking Generator Video Board The circle is produced using the principle of intersecting parabolas Line and field blanking waveforms are separately double integrated the first stage producing ramp waveforms and the second parabolas A crossing detector V209 ...

Page 13: ...counter are both high This stops the clock via D218 and 1 4 V214 D14 IC13 and the counters wait in this state until cleared by the next line blanking edge The 13 least significant addresses are used to address the RAMS V221 V224 IC18 The two most significant addresses are decoded in 1 2 V219 to select one of the four RAMs at a time simply addressed SMT The other 1 2 V219 IC 19 logic is used as a d...

Page 14: ...e output stage Since the charge produced by the pedestal pulse has to be dispersed uniformly with respect to the scanning beam the line flyback has to be linearised The half sine wave voltage is truncated by coupling using a secondary winding to the supply via a diode The current waveform is hence a linear sawtooth during flyback The shift control varies the dc bias through the scan coil A saturab...

Page 15: ...er produces 4KV from the EHT transformer output waveform A secondary winding of the EHT transformer also provides low voltage supplies for monitor field scan line shift alignments and battery indicator The video output of the equipment is displayed on the monitor by modulation of the control grid G1 RV113 is the gain contrast control and RV107 the dc level brightness control The focus is set by RV...

Page 16: ...Internal Assembly Details 14 Viewing Lens Scan Board Elapsed Time Indicator Iris Motor P4428 Internal View A ...

Page 17: ...Internal Assembly Details 15 Head Amp Video Board Shutter Blade Shutter Sensor P4428 Internal View B ...

Page 18: ...Internal Assembly Details 16 Viewing Lens Monitor Shutter Sensor Iris Motor Shutter Blade P4428 Internal View C ...

Page 19: ...Internal Assembly Details 17 Pevicon Tube Base Tube TubeClamp Yoke Adjustment Yoke Fixing Screws Yoke Neoprene Gasket Video to Scan Board Connector P4428 Internal View D ...

Page 20: ...Internal Assembly Details 18 Shutter Blade Retaining Screws 4 Iris Motor Shutter Motor Shutter Sensor Germanium Lens Iris Limit Switches Iris Drive Belt P4428 Internal View E ...

Page 21: ... the batteries together and do not mix cell types in one cartridge It is essential that the batteries are put into the carrier the correct way round refer to the diagram for correct positions 5 Replace the outer cover and tighten the retaining screw 6 Insert the battery cartridge into the voltage stabiliser unit and replace the cap LR6 is the IEC designation for AA size batteries using Alkaline Ma...

Page 22: ...nt current charge requiring 14 to 16 hours for a full charge of an empty set of cells The open circuit voltage of the cartridge is approximately 12V regardless of charge state It is fused at 1A The use of rechargeable cells will give inaccurate battery life indication as half scale to the camera end point will be only a few minutes As such it is not recommended for operational use 10 3 Illustratio...

Page 23: ...Batteries 21 ...

Page 24: ...h provided attached to the cap lanyard unscrew the central contact on the bottom of the battery pack 4 Remove the contact and fuse support rod be sure to retain the black separating ring 5 Remove the fuse through the slot in the centre of the battery 6 Replace the fuse with a ceramic 20mm 1A fuse 7 Replace the contact separating ring and fuse support rod and tighten 8 Replace the two batteries rem...

Page 25: ...Batteries 23 ...

Page 26: ...ering front earth tag and removing two screws on rear of chassis 3 With camera standing on its front remove the four front retaining screws taking care not to damage the shutter blade 4 Unplug P101 and carefully lift the camera chassis away from the front 5 Remove the chassis front plate and lens assembly complete by removing the four retaining screws see diagram page 18 6 Loosen the tube clamp re...

Page 27: ...Camera Disassembly 25 R F Screen Earth Tag Shown unsoldered Breech Ring Locating Notch Case Front Locating Screws Internal R F Screen P4428 Case Removal Diagram Shown without muff and harness ...

Page 28: ...is on alternate fields only February 1987 Scan Board to ESA 56492AA C171 changed from 0 1F to 0 22F R180 changed from 12k to 6k8 Video Processing to ESA 56493BA Diode D218 IN916 added as below Mod 5 Video Processing to ESA 56493CA Scan Board to ESA 54692A October 1987 Mod 6 Video Processing to ESA 56493CA Scan Board to ESA 54692AA Fitted with P4428 5 Scan Fitted with P4428 7 Video P4428K Cable res...

Page 29: ...changed applied to all cameras Change to RF screen Note that the spare parts for these cameras are different and not compatible with previous MOD levels Always quote the serial number when ordering spares January 1997 for EC customers Mod 10 New Scan PCB DAS 547526 AA New Video PCB DAS 547584 AA Boards redesigned due to component obsolescence issues and now using surface mount parts These are full...

Page 30: ...upply current The following checklists are designed so as to locate the possible area in which the fault lies based upon the easily observed or measured fault conditions For more detailed examination of faults these checklists refer to flow diagrams and waveforms located in the rear fold section of this manual Page numbers to which these refer will be given in the lists When working through the ch...

Page 31: ...l scene Checklist 1 1 Is there a picture Yes Go to Checklist 2 2 Is there any battery voltage indication Yes Go to Checklist 5 Switch off camera Remove battery cartridge and check fuse 3 Is fuse blown Yes Go to checklist 4 Check condition and orientation of batteries Replace complete battery cartridge with known working unit 4 Is there any change to camera condition Yes Restart checklist if any fa...

Page 32: ...old Replace lens assembly if mechanical failure of lens b Out of focus Plug in external monitor refer to page 32 i Is the picture in focus on the external monitor Yes Start monitor checklist page 49 rear fold Start focus regulator list page 46 rear fold c Bars or lines moving or stationary across picture Start motor checklist page 47 rear fold Start video checklist page 51 rear fold d Intermittent...

Page 33: ... 50 rear fold 2 Is there a raster on the internal monitor Yes Start Checklist 7 Remove case and connect external supply refer page and page Start and work through all scan checklists page 41 to page 46 rear fold than all video checklists page 51 to page 58 rear fold then tube base checklist page 60 rear fold Checklist 6 With external supply connected start voltage stabiliser checklist page 59 rear...

Page 34: ...the camera from its rear case 5 To replace reverse the above procedure whenever possible a new sealing ring should be fitted Connecting External Power Supply 1 Switch off the camera 2 Remove battery cartridge from the voltage stabiliser unit 3 Plug in battery substitution unit P4428D 4 Connect the red lead to 12V and the black lead to 0V of a current limited 1A d c supply Connecting External Monit...

Page 35: ...t P108 Check G3 80V TP105 Adjust using RV109 Check heater voltage on P 104 pins 3 to 6 or across 8 7V and R200 and change R200 if required to achieve 5 9 6 0V across the Pevicon heater 6 Open circular blanking RV206 7 Set beam current to 4µA using RV111 G1 Measure using a 3 5mm jack socket on the scan board and 50µA meter 8 Set pedestal by setting head amp output to 175mV measured at R219 R220 TP6...

Page 36: ...09 18 Adjust RV212 to minimise vertical patterning 19 Open circle RV206 until top and bottom of stored area is visible Centralise stored area RV211 In the case of a 525 line camera only the top stored area will be visible so RV211 maybe set fully clockwise Reset circle 20 Switch camera to chop mode and adjust RV210 to the centre of the range where there is no picture noise Switch camera to chop no...

Page 37: ...7 and RV106 27 Check and adjust optical focus by moving yoke assembly Check yoke rotation 28 Check LED battery indicators Adjust RV115 for offset and R114 for range no adjustment Rail drop out point should be below 9 2V 29 Check overall quality of picture and mechanical assembly ...

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