IBM 655743N Service Manual - Page 20

6557-03N/03S/43N/43S SECTION 4 ADJUSTMENTS • 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" shall be set at 128. • Landing Fine Adjustment 1. Put the set inside the Helmholtz coil. 2. Input the single green signal and set the "CONTRAST" to MAX. Landing adjustment after 2 hours of aging by Landing adjust- ment luminance. *Landing adjustment luminance :same luminance on aging (Reference: SIK=250uA) *Max luminance : 110 ch/m SIK=750uA 3. Demagnetize the metal part of the chassis with the hand de- gausser 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 "MON CON REG2"=152. Return to the original value after use.) Demagnetize the CRT surface with the hand degausser again. Note: (1) Adjust in a non-magnetic field. BV=45uT. (2) If adjusting in a magnetic fields, add the shift from the non-magnetic field in your estimation. 4. Attach the wobbling coil to the designated part of the CRT neck. 5. Pull the TLH plate nooked on stopper. 6. Attach the sensor of the landing adjustment unit on the CRT surface. 7. Adjust the DY position and purity, and the DY tilt, and land- ing of the center and 4 corners with the landing checker. Purity Adjustment use 2-pole magnet on DY side, Don't use on Neck Assy one. 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. A difference between red and blue must be within the specification given right. 0 ± 4 0 ± 7.5 0±4 0±5 0 ± 4 0 ± 7.5 (µm) 0 ± 4 0 ± 4 0 ± 4 ±5 ±5 ±5 ±5 ±5 ±5 (µm) ± 5 ± 5 ± 5 (µm) 8 8 8 8 7 8 8 8 8 * Adjustment and measurement should be made at the points one inch inside the fluorescent screen. 8. Tighten DY screw. Torque: 22±2 kgcm (2.2±0.2 Nm) Auto-degauss it. 9. Adjustment each top and bottom pins by switching DY neck up-down, and adjust V. TILT and horizontal trapezoid by swinging DY neck right-left. And then fix with 4 wedges. (Insert wedge certainly so that the DY will not loosen.) Fixing DY with wedges. a c "a" and "b" must be equal, and "c" and "d" must be almost equal. d b Apply a locking agent to the upper wedges only. In such a case, apply agent so that it enters both sides of wedge and also inside the DY. 10. Check landing at each corner and in case not in specification, adjust by sticking disk magnets on CRT funnel. (After placing disk magnets, absolutely hand degauss and check the results.) 11. Remove the sensor and wobbling coil. 12. Check that the DY is not tilting. Then, fix purity magnets with white paint and fix wedge with RTV. 4-1