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Summary of Contents for VR14

Page 1: ...VR14 VR17 CRT display monitor user s manual EK VR14 0P 005 digital equipment corporation maynard massachusetts...

Page 2: ...1972 1973 1974 by Digital Equipment Corporation The material in this manual is for infonnational purposes and is subject to change without notice Digital Equipment Corporation assumes no respon sibil...

Page 3: ...F OPERATION X AND Y DEFLECTION CIRCUITS 3 1 PLUS AND MINUS LOW VOLTAGE REGULATED SUPPLY 3 5 CRT ELECTRODE VOLTAGES 3 6 HIGH VOLTAGE POWER SUPPLY 3 6 W682 AND W684 INTENSITY CIRCUITS 3 10 LIGHT PEN AMP...

Page 4: ...Control G838 Circuit Diagram VRI4L VRI7L Brightness and Contrast Control Light Pen Amplifier Light Pen Pulse Timing G840 Module VRI4 VRI7 Interior View Deflection Heat Sink Removal 7007165 Power Regul...

Page 5: ...der certain conditions are potentially dangerous All electrical safety precautions must be observed Inherent implosion protection is employed in the CRT design however the tube may be damaged if it is...

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Page 7: ...Table 115 V Yes VR17 LD Table 230V Yes The VR14 versions without the light pen option contain a W682 Intensity Control Circuit Board and a G838 Fault Protection Circuit Board as well as a front panel...

Page 8: ...input and the differential input 6 Input offset not to exceed 1 2 peak to peak input signal 7 Maximum nonoperating input 50 V c Full screen deflection and settling time to within 1 spot diameter 18 J...

Page 9: ...here would be no deflection under these conditions Line power is passed through a fuse an on off switch and then through one normally closed thermal cutout switch The switch is located on the 22 V reg...

Page 10: ...OARD G836 80V X FEEDBACK THERMAL CUTOUT 22V 22 V FOCUS _ I I n u n I DEFLECTION YOKE 115VAC HIGH VOLTAGE POWER SUPPLY 10 500VDC ANODE 0 5 n II I I I CURRENT 22V X INPUT X POWER TRANSISTOR y y INPUT DE...

Page 11: ...V 22V 115VAC POWER SUPPLY a REGULATOR BOARD GS36 LIGHT PEN PULSE x INPUT I Y INPUT Y INPUT Y FEEDBACK THERMAL CUTOUT 22V 22V FOCUS 400V SOV SOY _ _ n I DEFLECTION YOKE 115VAC HIGH VOLTAGE POWER SUPPLY...

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Page 13: ...tely above the unit The table top model has a solid top cover The cooling air exits from the rear of the unit Therefore at least 2 inches of free space must be provided immediately behind the unit Do...

Page 14: ...d or contract the horizontal and vertical deflection to suit full screen requirements The position controls accommodate a 2 2 variety of input signals and allow offset inputs to be centered on the CRT...

Page 15: ...d to the CRT Pin 5 GND w Pin 6 GND Pin 7 A2B X Input One side of X input signal line x Input One side of X input signal line Pin 8 A2E X Input Other side of X input signal line X Input Other side of X...

Page 16: ...40 option Pin 19 AIH Not Used Light Pen Out Amplified light pen pulses Pin 20 JI8 Pin 12 Not Used 5 VIN Used in LK40 option N Pin 21 N C Pin 22 JI8 Pin 8 22 V 22 V is available if JI8 Pin 8 is 22V 22...

Page 17: ...chassis ground Signal ground is pin 9 and pin 12 X and Y signal ground Signal Name Function 22 V For VRI4 VRI7 options GND For VRI4 VRI7 options 22 V For VR14 VR17 options Bell Speaker Used with LK40...

Page 18: ...pre attenuation for these larger input signals The input signals may be bipolar such as 5 V or unipolar such 2 6 as 0 V to 5 V or 0 V to 5 V The position potentiometer allows the deflection to be offs...

Page 19: ...he display have gliches error spikes generated while changing values proportion ately longer delays are required since the deflection amplifiers have to recover from the gliches The Z direct input app...

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Page 21: ...wing in the yoke thus the amplifier compares the input voltage with the yoke current to ensure that the yoke CHAPTER 3 THEORY OF OPERATION 3 1 current is an exact replica of the input position signal...

Page 22: ...an emitter follower Q3 but the 2N4399 deHvers a11 the current and handles the necessary power dissipation re quirement 3 2 To minimize power consumption the output would like to operate in Class B i e...

Page 23: ...4 lK 01 C3 1I4W f DEC2219 P6 C7 5 10 E2 6 5 Cll R22 MC1520G RI5 220pF 680 9 4 C15 316 2W 7 1I8W I NC 3 1 C8 RI9 200 IW R21 10 10 rr g olF D6 CIO IN753A 6 8 olF 20 35V 6 2V 20 L R25 47 1 2W r 03 2N4923...

Page 24: ...the voltages necessary to operate El and E2 they are also used to generate the reference voltages with which the 3 5 output voltage will be compared The reference for the 22 V regulator is made with t...

Page 25: ...k to peak voltage to become positive D10 rectifies this voltage and CIS filters it the resultant output is 400 Vdc The 400 Vdc goes 3 6 directly to grid 2 If grid 2 i s not substantially positively bi...

Page 26: ...04 150V IK AE2 BP2 70VAC 80V 011 IN4004 R37 120 2W 012 10 IN4004 CI8 25JJ F 150V AF2 BRIG i L CI9 25 J F 150V GNO B02 BS2 l lI t_ J L L L L __ ____ L______l____________________L_______ ____J BJ2 3 I I...

Page 27: ...SELECT SWITCH l SELECT L VV I I R3 100 RIO lOOK I P 5 T D 1 F TO GRID 1 UNLESS OTHERWISE INDICATED DIODES ARE 0664 CAPAC ITORS ARE 100V 20 E I IS DEC7400N PIN 7 ON IC GND PIN 140N IC 5V RESISTORS ARE...

Page 28: ...as the input spike to B is above its 1 r high threshold level As soon as the spike decays below the threshold B s output immediately reverts to the high state B s output is fed back to A s input pin 1...

Page 29: ...varying brightness information may be coupled to the grid at pin D In the event of a failure of either the 22 V supplies deflection ceases and a bright spot could occur on the CRT causing a burn To p...

Page 30: ...s the control is turned clockwise dropping more voltage the brightness range between brightness level 0 and brightness level 7 is increased i e the image contrast is increased This is indicated in Fig...

Page 31: ...CRT safe Jl PEAKING CIRCUIT 3V 3 6 LIGHT PEN AMPLIFICATION The input from the 375 Light Pen that results from detection of beam intensification is not usable in its analog form it must first be conver...

Page 32: ...re of either 22 V supply deflection ceases and a bright spot occurs on the CRT resulting in a burn To prevent this the circuit on the G840 module that produces 5 V for the W684 intensity module will b...

Page 33: ...her damage Never leave power on to a malfunctioning or repaired VRI4 VRI7 until all necessary checkpoints are measured and proved nominal 4 1 CHAPTER 4 MAINTENANCE The circuit card connector block as...

Page 34: ...dc Voltage 43 Vdc Orange 42 Vdc Gray Yellow 22 Vdc Red 43 Vdc Green 42 Vdc Gray Blue 22 Vdc Blue Voltage 43 Vdc Ground 43 Vdc 3 5 Vrms Ground 3 5 Vrms 70 Vrms 200 P P 150 Vrms 400 P P 22 Vdc Red Groun...

Page 35: ...Blue oVdc Black 22 Vdc Blue Note All voltages measured with respect to ground chassis or A02V Pl P2 P3 J 7 4 10 7 4 13 10 5 2 8 5 2 11 8 5 2 14 11 6 3 9 6 3 12 9 6 3 15 12 7007165 8RIGHTNESS FOCUS AD...

Page 36: ...should be replaced or repaired refer to Appendix C 8 Repeat the same tests as in step 7 for the Y axis deflection circuit A225 plugged into A03 Monitor A03 A Refer to Appendix C for A225 repair 4 4 9...

Page 37: ...tricted generally to improper input signals especially grounding techniques or faults on the A225 circuit board If input signals are not suspect a faulty A225 may be isolated by swapping X and Y A225s...

Page 38: ...g the deflection sink to the rear panel b Remove heat sink assembly and its connectors if necessary and remove faulty power transistor Later models do not have the four BNC connectors at the top rear...

Page 39: ...ector while pulling the connector straight up allowing the locking tabs to pass through the square holes they were butted against Do not pull the connector by its wires only by its plastic body TO VR1...

Page 40: ...unting screws from the opposite side of the vertical chassis wall b Reconnect connectors and place a cardboard under the 7007165 to prevent shorting out the circuit against the chassis when troublesho...

Page 41: ...the yoke gets stuck at the socket end of the CRT because the yoke 4 9 plastic mounting piece hugs the CRT neck tightly and must be spread to pass over the CRT socket To remove the CRT proceed as fol1...

Page 42: ...ink mounting screws from the side chassis Remove two pin connector from the high voltage bracket b Lift heat sink straight out and repair faulty transistor NOTE Thermal cutouts have line voltage on th...

Page 43: ...th the support bracket screw holes Once the clamp tubes are aligned and the CRT fastened to the support bracket tighten the worm gear clamp 4 11 4 3 S High Voltage Supply Removal To remove the high vo...

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Page 45: ...1 C MU VR14 O 3 A PL VR14 O 3 D CS G836 O 1 D CS G840 O 1 B CS G838 0 1 A PL G838 0 O D CS A22S 0 1 D CS W684 O 1 B CS W682 O 1 A PL W682 O 0 C IA 7009248 O O C CS 7007080 O 1 C CS 7007082 O 1 D CS 7...

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Page 47: ...t If the A I APPENDIX A POWER SUPPLY TROUBLESHOOTING regulator circuits are not working the output could be beyond its nominal value The MCl709 is the most likely suspect followed by the drive transis...

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Page 49: ...ases a plus voltage at A02 A or A03 A means the PNPs 2N4399 are at fault These are the lower transistors on both sides If the voltage APPENDIX B DEFLECTION AMPLIFIER B 1 TROUBLESHOOTING at A02 A or A0...

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Page 51: ...be replaced If only half deflection is working no positive current or no negative current C I APPENDIX C A225 REPAIR capability and the power transistors are operating properly Q3 should be replaced f...

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Page 53: ...te well organized well written etc Is it easy to use What features are most useful What faults do you find with the manual Does this manual satisfy the need you think it was intended to satisfy Does i...

Page 54: ...USINESS REPLY MAIL NO POSTAGE STAMP NECESSARY IF MAILED IN THE UNITED STATES Postage win be paid by Digital Equipment Corporation Technical Documentation partment 146 Main Street Maynard Massachusetts...

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