Nokia 920C Service Manual

Contents

Nokia 920C Service Manual Manual pdf 8 page image

4-1-1 Before Making Adjustments4-1-1 (a) ORIENTATIONWhen servicing, always face the monitor to theeast.4-1-1 (b) MAGNETIC FIELDSWhenever possible, use magnetic field isolationequipment such as a Helmholtz field to surroundthe monitor. If a Helmholtz field is not available,frequently degauss the unit under test.Caution: Other electrical equipment may causeexternal magnetic fields which mayinterfere with monitor performance.Use an external degaussing coil to limit magneticbuild up on the monitor. If an external degaussingcoil is not available, use the internal degaussingcircuit. However, do not use the internaldegaussing circuit more than once per 30 minutes.4-1-1 (c) WARM-UP TIMEThe monitor must be on for 30 minutes beforestarting alignment. Warm-up time is especiallycritical in color temperature and white balanceadjustments.4-1-1 (d) SIGNALAnalog, 0.7 Vp-p positive at 75 ohm, internalterminationSync: Separate/Composite(TTL level negative/positive)Sync-on-Green:Composite sync 0.3 Vp-p negative(Video 0.7 Vp-p positive)4-1-1 (e) SCANNING FREQUENCYHorizontal: 30 kHz to 96 kHz (Automatic)Vertical: 50 Hz to 160 Hz (Automatic)Unless otherwise specified, adjust at the1024 x 768 mode (H: 68 kHz, V: 85 Hz) signals.Refer to Table 2-1 on pages 2-2 and 2-3.4-1-1 (f) HIGH VOLTAGE ADJUSTMENTSignal: 1024 x 768 mode (68 kHz/85 Hz)Display image: Full whiteContrast: MaximumBrightness: MaximumLimit: 27.3 kV ± 0.5 kV(17”: 26 kV ± 0.5 kV)Measure the hight voltage level at the anode cap.High voltage should be within the limit as above.If the high voltage needs adjustment, use the VR501.4-1-1 (g) G2 (SCREEN) VOLTAGE ADJUSTMENTSignal: 1024 x 768 mode (68 kHz/85 Hz)Display image: Full whiteContrast: MaximumBrightness: MaximumAdjust the Screen VR of the FBT so that the G2(Screen) Voltage for Toshiba it is 540 V ± 10 V.4-1-1 (h) CENTER RASTERAdjust VR401 so that the back raster comes to thecenter when you apply a signal of 91 kHz/85 Hz.720C/920C 4-14 Alignment and AdjustmentsThis section of the service manual explains how to make permanent adjustments to the monitor. Directionis given for adjustment using the monitor Interface Board Ver. 2.0 and software (Softjig).4-1 Adjustment ConditionsCaution: Changes made without the Softjig are saved only to the user mode settings. As such, thesettings are not permanently stored and may be inadvertently deleted by the user.720C SDD TOSHIBAG2 525V 635V920CG2 560V 530VMEC SDD