PHILIPS GDMFW900
Service Manual

SECTION 4 ADJUSTMENTS

GDM-FW900

Note: Hand degauss must be used on stand-by or power-off condition. This model has an automatic earth magnetism correction function by using an earth magnetism sensor and a LCC coil. When using a hand degauss while monitor (LCC coil) is being operated, it sometimes gets magnetized, and the system may not work properly as a result. � Landing Rough Adjustment 1. Enter the full white signal. (or the full black dots signal). 2. Adjust the contrast to the maximum. 3. Make the screen monogreen. Note: Off the outputs from R ch and B ch of SG. 4. Reverse the DY, and adjust coarsely the purity magnet so that a green raster positions in the center of screen. 5. Adjust the tilt of DY, and fix lightly with a clamp. Note: �TILT� = �128�. � Landing Fine Adjustment 1. Put the set inside the Helmholtz coil. (�LCC SW� = �12�) 2. Input the single green signal and set the �CONTRAST� = �255�. Note: After the W/B adjustment with 9300K, measure an average of ΣIk when a full white signal is entered in the CONT MAX/BRT CENT status. Then make adjustment so that the specified screen can be attained after aging for 2 hours with Ik equivalent to 30% of the average value. 3. Demagnetize the metal part of the chassis with the hand degausser and coil degausser, and the CRT surface with the hand degausser. Input AC 230V to AC IN, turn on and off the power to perform auto degaussing. (Perform auto degaussing by setting �FUNCTION SW� = 1. Return to the original value after use.) Demagnetize the CRT surface with the hand degausser again. Note: (1) Hand degauss must be used on stand-by or power-off condition. This model has an automatic earth magnetism correction function by using an earth magnetism sensor and a LCC coil. When using a hand degauss while monitor (LCC coil) is being operated, it sometimes gets magnetized, and the system may not work properly as a result. (2) Adjust in a non-magnetic field. (3) If adjusting in a magnetic fields, add the shift from the nonmagnetic field in your estimation. 4. Attach the wobbling coil to the designated part of the CRT neck. 5. Attach the sensor of the landing adjustment unit on the CRT surface. 6. Adjust the DY position and purity, and the DY tilt, and landing of the center and 4 corners with the landing checker. After adjustment, set �LCC SW� to �13�.

� Write terrestrial magnetism sensor reading VX and VY to �LCC VX� and LCC VY� respectively. Adjust the landing by moving �LCC NS�, �LCC LT�, �LCC LB�, �LCC RT� and �LCC RB�. However, the register adjustment must be limited within the following range. �LCC NS� 128 ± 45 �LCC LT�, �LCC LB�, �LCC RT�, �LCC RB� 128 ± 40 Save the service data. <Specifications> Adjust so that the green is within the specification given right. 4 corner adjust target : within ± 1 The red and blue must be within the specification given right with respect to the green.
(µm) 0 ± 3 0 ± 7.5 0 ± 3 0 ± 3 0 ± 7.5 0 ± 3 0 ± 3 0 ± 7.5 0 ± 3 (µm) ±6 ±6 ±6 (µm) 10 10 10

±6 ±6 ±6

±6 ±6 ±6

A difference between red and blue must be within the specification given right.
10 10 10 10 7 10

* Adjustment and measurement should be made at the points one inch inside the fluorescent screen. 7. Tighten DY screw. Note: Torque 22 ± 2 kg.cm (2.2 ± 0.2 Nm) auto degauss it. 8. For the up/down swing, swing the DY and insert a wedge so that the up and down pins are equal at the top and bottom. Adjust the H.TRP VR of DY so that the horizontal trapezoid is equal at the left and right. Insert the wedge firmly so that the DY does not shake. 9. Check the landing of each corner, and if it does not satisfy the specification, adjust the landing of four corners using �LCC LT�, �LCC LB�, �LCC RT� and �LCC RB�. However, the register adjustment must be limited within the following range. �LCC NS� 128 ± 15 �LCC LT�, �LCC LB�, �LCC RT�, �LCC RB� 128 ± 45 After adjustment, save the service data. 10. Remove the sensor and wobbling coil. 11. Switch the signal to R.G.B., and check that each color is pure. 12. Check that the DY is not tilting, and fix the purity Mg with a white pen. Fix wedges with RTV.

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