DEC VR315 Service Manual Download

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Aligning the Video Monitor

4–11

4.6 GAIN Adjustment

Set the Contrast control to maximum and Brightness control for
background extinction.

Set GAIN using the All-White pattern to obtain 0.283 luminance at
the screen center.

MA-0300-90.DG

G a i n

Figure 4–7

GAIN, G2, and FOCUS (G4) Adjustments

Summary of Contents for VR315

Page 1: ...VR315 and VR325 Monochrome Monitors Service Guide Order Number EK VR315 SV 002 Digital Equipment Corporation ...

Page 2: ...hat is not supplied by Digital Equipment Corporation or its affiliated companies Restricted Rights Use duplication or disclosure by the U S Government is subject to restrictions as set forth in subparagraph c 1 ii of the Rights in Technical Data and Computer Software clause at DFARS 252 227 7013 Copyright Digital Equipment Corporation 1991 All Rights Reserved Printed in U S A The following are tra...

Page 3: ...ng and Replacing FRUs 3 1 Introduction 3 1 3 1 1 Removing the External Cables 3 2 3 1 2 Removing the Rear Cover 3 3 3 1 3 Removing the Top Cover 3 4 3 2 Field Replaceable Units FRUs 3 5 3 2 1 Interconnect Cable 3 6 3 2 2 Power Supply Module 3 8 3 2 3 Discharging the CRT and Removing the Anode Cap 3 10 3 2 4 Deflection Module 3 12 3 2 5 Video Casting Assembly 3 16 3 2 6 CRT Chassis Assembly 3 20 3 ...

Page 4: ...oving Cables from the Monitor 3 2 3 2 Rear Cover Removal 3 3 3 3 Top Cover Removal 3 4 3 4 Field Replaceable Units 3 5 3 5 Disconnecting the Interconnect Cable 3 7 3 6 Removing the On Off Switch Cable from the Power Supply 3 8 3 7 Removing the Power Supply 3 9 3 8 Discharging the CRT and Removing the Anode Cap 3 11 3 9 Loosening the Captive Screw 3 13 3 10 Disconnecting Cables from the Deflection ...

Page 5: ...iance Meter 4 9 4 6 Using the Radiance Meter 4 10 4 7 GAIN G2 and FOCUS G4 Adjustments 4 11 Tables 1 1 Tools and Equipment 1 2 1 2 Recommended Spare Parts 1 3 2 1 Blank Screen No Video or Raster 2 3 2 2 Blank Screen No Video but Raster is Present 2 5 2 3 Poor Display Quality 2 6 4 1 Monitor Controls and Indicators 4 2 ...

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Page 7: ...ures Chapter 3 provides the removing and replacing procedures for the Field Replaceable Units FRUs Chapter 4 describes the alignment procedures Appendix A describes related documentation Conventions Convention Meaning Caution Provides information to prevent damage to the equipment Warning Provides information that relates to personal safety Note Provides general information PN Refers to a part num...

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Page 9: ...d antiglare screen with an auto ranging power supply for worldwide operation Its built in tilt swivel base lets the user adjust the screen for viewing comfort When connected to a host system the monitor displays information sent by the host MA 0299 90 DG Figure 1 1 Monochrome Monitor 1 1 ...

Page 10: ...isphere VR325 D4 Southern hemisphere 1 2 Tools and Equipment Table 1 1 lists the tools and equipment you will need to service the monitor Table 1 1 Tools and Equipment Tools and Equipment Part Number Terminal technician tool kit 29 27340 01 Static protection kit 29 26246 00 Anode discharge tool 29 24717 00 Metric measuring tape 29 25342 00 Safety goggles 29 16141 00 Gloves 29 16146 00 ...

Page 11: ...arts Spare Part VR315 Part Number VR325 Part Number Power supply 54 19629 02 54 19629 03 Deflection module 54 19826 01 54 19826 02 Video casting assembly 70 27073 01 70 27073 01 Module interconnect cable 70 27000 02 70 27000 02 CRT chassis assembly Northern Hemisphere 70 27477 01 70 27481 03 Southern Hemisphere 70 27477 02 70 27481 04 ...

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Page 13: ...of problem tell the customer to warm the monitor up for at least 20 minutes if possible before you arrive and begin the troubleshooting procedures Magnetic fields affect monitor performance and can give a false indication of a monitor failure Place the monitor away from any electromagnetic devices such as printers and terminals or away from large magnetized objects such as filing cabinets and stee...

Page 14: ... the suggested solutions 4 Display the host system alignment test patterns to make sure that no other problem exists Refer to the host system service guide for displaying test patterns 2 3 Troubleshooting Tables The troubleshooting tables list the possible cause in order of probability This troubleshooting information applies to three types of video problems that the monitor may exhibit A blank sc...

Page 15: ...another wall outlet If the problem continues call the facilities person Power supply module is faulty Replace the power supply module Section 3 2 2 Deflection module is faulty Replace the deflection module Section 3 2 4 Video module is faulty Replace the video casting assembly Section 3 2 5 No video or raster but the power indicator is on Brightness or contrast is set incorrectly Adjust the bright...

Page 16: ...r indicator and LED on the deflection module are on Internal cabling is loose or faulty Check all cabling going to the deflection module and the video casting assembly including the CRT socket connector If necessary secure the cables G2 Bias is set incorrectly Correct the G2 adjustment Section 4 5 Signal cable is faulty Replace the signal cable Refer to the host system documentation Deflection mod...

Page 17: ...aulty Check all the cables to the deflection module and the video casting assembly The host system is not supplying video signals to the monitor Connect the monitor to a known working host system if available to verify the problem before replacing any monitor modules Host system is faulty Repair the host system Video casting assembly is faulty Replace the video casting assembly Section 3 2 5 Defle...

Page 18: ...ection module is faulty Replace the deflection module Section 3 2 4 CRT chassis assembly is faulty Replace the CRT chassis assembly Section 3 2 6 only after trying the previous solutions Poor light output using the all white diagnostic pattern The Display is not bright enough The brightness or contrast control is set incorrectly Adjust the brightness and contrast controls Host system is not supply...

Page 19: ...tor or move the monitor Deflection module is faulty Replace the deflection module Section 3 2 4 Faulty CRT chassis assembly Replace the CRT chassis assembly Section 3 2 6 only after trying the previous solutions Video noise Display has intermittent flashing or changes in brightness The signal cable is loose or faulty Reseat the connectors or replace the signal cable Video casting assembly is fault...

Page 20: ...Quality Symptom Possible Cause Suggested Solution Video casting assembly is faulty Replace the video casting assembly Section 3 2 5 CRT chassis assembly is faulty Replace the CRT chassis assembly Section 3 2 6 only after trying the previous solutions ...

Page 21: ...at are easily accessed and removed from the rear of the monitor No special tools are needed and self retaining hardware is used The procedures describe how to remove the FRUs To install each FRU do the reverse of the removal procedure WARNING Turn power to the monitor off before performing any of these procedures NOTE Before removing any FRUs you must remove the rear cover and the top cover 3 1 ...

Page 22: ...lug the power cord from the power source wall outlet or host system first then from the monitor 3 Remove the signal cable from the rear of the monitor NOTE Push the connector in and rotate it to the left until the signal cable is released from the connector Power Source From Host System Power Cord M A 0 2 2 5 9 0 D G Figure 3 1 Removing Cables from the Monitor ...

Page 23: ... rear cover as follows 1 Remove the external cables Section 3 1 1 2 Use a Phillips screwdriver to remove the four screws that hold the rear cover to the enclosure Figure 3 2 3 Remove the rear cover by pulling the cover towards you MA 0226 90 DG Figure 3 2 Rear Cover Removal ...

Page 24: ... 1 3 Removing the Top Cover Remove the top cover as follows 1 Remove the rear cover Section 3 1 2 2 Tilt the top cover up and slide it toward the rear of the monitor Figure 3 3 Top Cover M A 0 2 2 7 9 0 D G Figure 3 3 Top Cover Removal ...

Page 25: ... replacing any FRU tilt the monitor from the back to the front to allow easier access to the modules WARNING Turn the power off before disconnecting or replacing any FRU CRT Chassis Assembly Deflection Module Interconnect Cable Video Casting Assembly Power Supply MA 0228 90 DG Figure 3 4 Field Replaceable Units ...

Page 26: ... cable as follows 1 Remove the rear cover Section 3 1 2 2 Remove the top cover Section 3 1 3 3 Disconnect the interconnect cable in the following order Figure 3 5 FRU Connector Interconnect Cable Plug Power supply right J1 P1 Video casting center J2 P2 Deflection module left J3 P3 ...

Page 27: ...erconnect cable verify that the pull tab labeled P2 is above the cable connector on the deflection module You can damage the monitor if this cable is replaced incorrectly Interconnect Cable M A 0 2 2 9 9 0 D G 1 2 3 Figure 3 5 Disconnecting the Interconnect Cable ...

Page 28: ...over Section 3 1 3 3 Remove the interconnect cable Section 3 2 1 4 Disconnect the 3 wire 5 pin On Off switch cable P4 from the connector J4 at the top of the power supply by pressing the tab on top of the connector Figure 3 6 M A 0 2 3 0 9 0 D G Power Supply 3 Wire 5 Pin On Off Switch Cable Figure 3 6 Removing the On Off Switch Cable from the Power Supply ...

Page 29: ...cing FRUs 3 9 5 Loosen the captive screw that holds the power supply to the chassis Figure 3 7 6 Slide the power supply module out of the card guides M A 0 2 3 1 9 0 D G Power Supply Figure 3 7 Removing the Power Supply ...

Page 30: ...steps expose you to the CRT anode which may store a high voltage 5 Attach the clip end of the anode discharge tool PN 29 24717 00 to a chassis ground point near the CRT anode WARNING Keep your free hand away from any part of the monitor during the anode discharge process 6 Using one hand carefully slip the anode discharge tool under the CRT anode connector cup until it touches the connector prongs...

Page 31: ...lacing FRUs 3 11 M A 0 2 3 2 9 0 D G A Push in the direction of the arrow B When one barb is free push in the opposite direction see arrows to remove anode cap Figure 3 8 Discharging the CRT and Removing the Anode Cap ...

Page 32: ...he CRT and remove the anode cap Section 3 2 3 WARNING You must complete the discharge procedure for the CRT Section 3 2 3 before removing the deflection module 5 Remove the interconnect cable Section 3 2 1 6 Loosen the captive screw that holds the deflection module to the chassis Figure 3 9 7 Remove the 2 wire 3 pin G2 and Focus cable P7 from the connector J7 at the top of the video casting assemb...

Page 33: ...Removing and Replacing FRUs 3 13 2 Wire 3 Pin Cable 6 Wire 8 Pin Brightness Contrast Cable M A 0 2 3 3 9 0 D G Deflection Module Video Casting Assembly Figure 3 9 Loosening the Captive Screw ...

Page 34: ...e tab on top of the connector 10 Disconnect the multicolored 6 wire 9 pin CRT yoke cable P11 from the connector J11 on the deflection module by pressing the tabs on the connector Figure 3 10 MA 0234 90 DG 1 9 Wire 9 Pin Raster Control Cable 2 6 Wire 9 Pin CRT Yoke Cable 2 6 Wire 9 Pin CRT Yoke Cable Figure 3 10 Disconnecting Cables from the Deflection Module ...

Page 35: ...Removing and Replacing FRUs 3 15 11 Slide the deflection module out of the card guides Figure 3 11 Card Guide Deflection Module MA 0235 90 DG Figure 3 11 Removing the Deflection Module ...

Page 36: ... wire 3 pin cable P4 from the connector J4 at the top of the video casting assembly Figure 3 12 by pressing on the sides of the connector and pulling You may need a small screwdriver to assist in releasing the tabs 5 Disconnect the 6 wire 8 pin brightness contrast cable P5 from the connector J5 at the bottom of the video casting assembly by pressing the top center tab on the connector Place the ca...

Page 37: ...Contrast Cable Figure 3 12 Removing Cables from the Video Casting 6 Gently push the CRT socket connector off the socket pins Figure 3 13 CAUTION When you install the video casting assembly carefully push the CRT socket connector onto the CRT neck Use care not to bend the pins during this procedure ...

Page 38: ... D G Socket Pins CRT Socket Connector Figure 3 13 Removing the CRT Socket Connector 7 Loosen the captive screw at the top of the video casting Figure 3 14 8 Gently pull the top of the video casting assembly towards you and lift it out of the chassis ...

Page 39: ...Removing and Replacing FRUs 3 19 M A 0 2 3 7 9 0 D G Video Casting Assembly Figure 3 14 Removing the Video Casting ...

Page 40: ...Section 3 2 1 4 Remove the power supply module Section 3 2 2 5 Discharge the CRT and remove the anode cap Section 3 2 3 WARNING You must discharge the CRT and remove the anode cap Section 3 2 3 before removing the deflection module 6 Remove the deflection module Section 3 2 4 7 Remove the video casting assembly Section 3 2 5 NOTE After removing the above FRUs the remaining part is the CRT chassis ...

Page 41: ...about replacing and disposing of CRTs This procedure is for Digital personnel only and is not intended for use by OEM and self maintenance customers Location Work in areas where risks and exposure are limited to trained Digital personnel Only Digital personnel should be in the area during CRT removal and replacement Handling a CRT Never handle the CRT by the neck Always use two hands and hold the ...

Page 42: ...dle pieces of phosphor coated glass without wearing protective gloves Before you perform the following procedure remove the FRUs listed in Section 3 2 6 1 Place the old CRT chassis assembly and the original packing material in the container from which you removed the new CRT chassis assembly 2 Using pliers slowly crush but do not snap the evacuation point Figure 3 15 Do not move or disturb the CRT...

Page 43: ...3 15 Crushing the Evacuation Point 3 Seal the carton with packing tape and dispose of it in the Digital site s trash receptacle NOTE The safe gassing of the CRT is necessary to prevent liability and safety problems that may arise from accidental CRT implosion ...

Page 44: ...nitor apart Use the following procedure to put the tilt swivel base back on the monitor 1 Place the monitor screen side down on a soft pad 2 Align the tilt swivel base with the wider part downward toward the screen Figure 3 16 3 Place a curved tool like a long Allen wrench through the center of the swivel retainer inside the base 4 While pressing on the base with one hand pull the swivel retainer ...

Page 45: ...Removing and Replacing FRUs 3 25 MA 0239 90 DG Teeth of Swivel Clamp Monitor Base Monitor Bottom View Figure 3 16 Tilt Swivel Base ...

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Page 47: ...ts You must use the screen alignment test patterns to make all adjustments Refer to your host system documentation to set up test patterns 4 1 1 Before You Start NOTE If a customer calls with a display quality type of problem ask the customer to leave the monitor on until you arrive Then after removing the rear cover only a 5 minute warm up is needed Clean the Monitor Use a soft tissue or cloth an...

Page 48: ...ntrols and Indicators Item Control Indicator Function Power switch indicator Turns the power on and off When the power is on the switch is lit up For extended monitor life switch the power off when not in use Contrast Adjusts the video display intensity Brightness Adjusts the video background intensity Rotation Rotates the video display area Horizontal centering Adjusts the horizontal position of ...

Page 49: ...Aligning the Video Monitor 4 3 1 4 5 6 M A 1 2 9 5 8 9 D G 2 3 7 Figure 4 1 User Controls and Indicator ...

Page 50: ...e CRT heater filament 4 1 3 Displaying Screen Tests The procedures in this chapter refer to a circle crosshatch alignment test pattern Figure 4 2 and an all white test pattern Display them on the screen as needed by using procedures for your host system Refer to the host system service guide for accessing these diagnostic screen patterns M A X 0 8 8 9 8 8 Figure 4 2 Circle Crosshatch Pattern ...

Page 51: ... at a stable temperature before you do any adjustments NOTE In the following steps use a metric measuring tape PN 29 25342 to measure the dimensions of the screen display To avoid scratching the screen with the tape s metal clip start the measurement at 10 cm See Figure 4 3 10 11 9 199 mm VR315 236 mm MA 0301 90 DG VR325 265 mm LJ 00545 TI0 Figure 4 3 Using the Metric Measuring Tape ...

Page 52: ... affects the display size Adjust the anode voltage as follows 1 Mark the position on the ANODE potentiometer where the display size is maximized and minimized by turning it in one direction and then the other 2 Set the ANODE potentiometer to the half way point between where the display size was at a maximum and at a minimum 4 3 3 Height and Width Adjustments Check and adjust linearity as follows 1...

Page 53: ...in Width HCen HLin G2 Focus G4 Anode HPhase VCen VLin Height VHold Gain Gain Figure 4 4 Internal Controls 8 Adjust VCEN Figure 4 4 so that the display is centered in the bezel 9 Set HEIGHT so that the center to the bottom half of the dimension is correct 10 Adjust VLIN so that the center rectangles are the same size as the bottom and top rectangles ...

Page 54: ...ccluder or you may damage the radiance meter Do not touch the exposed filter after the protective cap is removed 2 Connect the ac line adapter to the radiance meter and plug the adapter into a wall outlet NOTE Ensure that your radiance meter is in calibration 3 Turn the power switch to on NOTE Do not use the POWER ON W BACKLIGHT position when you are using the radiance meter with batteries 4 Set t...

Page 55: ...wer Switch Range Switch MA X0665 88A Figure 4 5 Radiance Meter 5 Place the occluder firmly against the center of the screen Figure 4 6 Take a red china pencil to draw an arc or circle around the occluder NOTE You must take all meter readings with the meter centered in this arc or circle ...

Page 56: ...l use the radiance meter on the screen Figure 4 6 Check and adjust G2 Figure 4 7 as follows 1 Set the Brightness to minimum and Contrast controls to maximum 2 Set G2 using the raster pattern so that the maximum background luminance is 0 010 3 Display the Circle Crosshatch pattern and set FOCUS G4 for best overall sharpness ...

Page 57: ...tment 1 Set the Contrast control to maximum and Brightness control for background extinction 2 Set GAIN using the All White pattern to obtain 0 283 luminance at the screen center G2 MA 0300 90 DG G4 Gain Figure 4 7 GAIN G2 and FOCUS G4 Adjustments ...

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Page 59: ...and indicators VR315 VR325 Monochrome Monitor IPB EK VR315 IP 002 This document provides a detailed parts breakdown of the VR315 and VR325 field replaceable parts The documents do not contain part numbers for components on the printed circuit modules However these components are listed in the Field Maintenance Print Set ordered separately VR315 Field Maintenance Print Set MP 03013 01 This document...

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