Focus Adjustment; Purity Adjustment - Mitsubishi Diamond Pro 750SB Service Manual

12. Focus Adjustment

(A) Mode: No.12, 9300K
(B) Pattern: Green Crosshatch, Brightness just cut off, Contrast maximum.
(C) Adjust V- Parabola Vp-p by OSD V-Focus control in Factory Mode. V focus: 60% of control bar.
(D) Check T303 output voltage of the video range.
H-para=300V ±30V
Horizontal
(E) Adjust F1 VR of FBT (lower side VR) for the vertical line to become fine line.
(F) Adjust F2 VR of FBT (higher side VR) for the horizontal line to become fine line.
(G) Receive Focus adjustment pattern.
(H) Adjust F1 VR if vertical black line is not falling out.
(I) Adjust F2 VR if horizontal black line is not falling out.
(J) Use the video card "Matrox G550", and receive Microsoft Excel "Work sheet" (1280*1024(85)).
Make sure that there is no double line for horizontal at the center.
*Note: Focus adjustment must be finished at F1 VR.
FOCUS ADJUSTMENT PATTERN

13. Purity Adjustment

(1) Receive signal 12 (Cross hatch pattern).
(2) The CRT face should be facing east and degauss the entire unit by external degaussing coil.
(3) Make sure the single color purity.
If not, readjust CPC magnet and touch up using correction magnets.
The shape of black dot (1 dot) fall out.
The shape of black dot (2dots) fall out .
V-para=150V ±10V.
Black dot is fall out
F1 VR
F2 VR
G2 VR
4-8
Vertical
Focus VR