NEC DPro2070SB Service Manual page 75

3. TROUBLESHOOTING
This chapter for troubleshooting is useful if any normal conditions cannot be secured even after the
confirmation of "Troubleshooting" presented in the User's Manual and the completion of "Chapter 3. Adjustment
procedures" presented in this Service Manual.
The equipment units related to the possible cause of "Picture bounces or a wavy patterns is present in the picture
" described in "Troubleshooting" presented in the User's Manual include the electrical equipment such as portable
telephones, etc., which may generate electromagnetic waves. Therefore, troubleshooting actions should be taken
after turning off the portable telephones, etc., and such electrical equipment that may generate electromagnetic waves,
or in a place distant from such equipment.
Contents
3.1 No Raster Generated ---------------------------------------------------------------------------------------------------------- 3-2
3.2 Abnormal Picture --------------------------------------------------------------------------------------------------------------- 3-4
3.2.1 Raster Brightness Failure ----------------------------------------------------------------------------------------------- 3-4
3.2.2 Image Color Failure or Contrast Failure ----------------------------------------------------------------------------- 3-4
3.2.3 Sync Failure ---------------------------------------------------------------------------------------------------------------- 3-5
3.2.3.1 Horizontal Sync Unstable ----------------------------------------------------------------------------------------- 3-5
3.2.3.2 Vertical Sync Unstable -------------------------------------------------------------------------------------------- 3-6
3.2.4 Screen Size and Screen Position Failure --------------------------------------------------------------------------- 3-7
3.2.4.1 Horizontal Size Failure -------------------------------------------------------------------------------------------- 3-7
3.2.4.2 Horizontal Position Failure --------------------------------------------------------------------------------------- 3-8
3.2.4.3 Vertical Size and Position Failure ------------------------------------------------------------------------------- 3-8
3.2.5 Linearity Failure ----------------------------------------------------------------------------------------------------------- 3-9
3.2.5.1 Horizontal Linearity Failure --------------------------------------------------------------------------------------- 3-9
3.2.5.2 Vertical Linearity Failure ---------------------------------------------------------------------------------------- 3-10
3.2.6 Distortion Compensation Circuit Failure -------------------------------------------------------------------------- 3-11
3.2.6.1 IN/OUT (pincushion), ALIGN (trapezoidal) and TOP/BOTTOM (corner correction) Failure --- 3-11
3.2.6.2 LEFT/RIGHT (pincushion balance), TILT (parallelogram), and TOP BALANCE/BOTTOM
BALANCE (corner correction) Failure ---------------------------------------------------------------------- 3-11
3.2.6.3 ROTATE (raster rotation) Failure ----------------------------------------------------------------------------- 3-11
3.2.7 Focus Failure ------------------------------------------------------------------------------------------------------------ 3-12
3.3 Functional Errors -------------------------------------------------------------------------------------------------------------- 3-14
3.3.1 OSM Failure -------------------------------------------------------------------------------------------------------------- 3-14
3.3.2 Power Management Functional Operation Error ---------------------------------------------------------------- 3-15
3.3.3 Plug & Play (DDC2B) Operation Error ----------------------------------------------------------------------------- 3-16
3.3.4 Degaussing Functional Operation Error --------------------------------------------------------------------------- 3-16
3.3.5 Earth Magnetism Canceling Functional Operation Error ---------------------------------------------------------3-17
3.3.6 Key Operation Error ---------------------------------------------------------------------------------------------------- 3-17
3.4 Circuit Errors ------------------------------------------------------------------------------------------------------------------- 3-18
3.4.1 Power Circuit Failure --------------------------------------------------------------------------------------------------- 3-18
3.4.2 Horizontal Oscillation / Deflection Circuit Failure --------------------------------------------------------------- 3-19
3.4.3 Vertical Oscillation / Deflection Circuit Failure ------------------------------------------------------------------- 3-20
3.4.4 HV Circuit Failure ------------------------------------------------------------------------------------------------------- 3-21
3.4.5 Video Circuit Failure ---------------------------------------------------------------------------------------------------- 3-22
3.4.6 Static Convergence Compensation Circuit Failure ------------------------------------------------------------- 3-24
3.4.7 Corner Purity Compensation Circuit Failure --------------------------------------------------------------------- 3-25
3.4.8 MPU Operation Error -------------------------------------------------------------------------------------------------- 3-26
3.4.9 Self-Diagnostic Functions --------------------------------------------------------------------------------------------- 3-27
3.4.10 USB Circuit Failure -------------------------------------------------------------------------------------------------------3-28
3-1
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