Table of Contents
ii
WFM90D and WFM91D Service Manual
Variable Gain Range and Vertical Position Range 4-- 7.......................
Overscan 4-- 8.......................................................
Input and DC Restorer Frequency Response 4--9...........................
Vector Phase Stability 4-- 11.............................................
Chrominance Bandwidth 4-- 12..........................................
Audio Gain and Frequency Response 4--13................................
Performance Verification: Digital Section 4--15......................
Check Sync Separation 4--15............................................
Check Frequency Response 4--16........................................
Check Frequency Response at X5 Gain 4--17...............................
Adjustment Procedures
Adjustments 5--1..............................................
Summary Adjustment 5-- 1.............................................
Equipment Required 5--2..............................................
Adjustment Procedures 5--3............................................
Adjustment Procedures: Analog Section 5--5.......................
Raster VCO 5--5.....................................................
Sweep Timing and Horizontal Mag Registration 5-- 5........................
Vertical Gain and X5 Gain Registration 5-- 7...............................
Frequency Response 5--7..............................................
Vector Quadrature Phase 5 --9..........................................
VectorGainandX5GainPhase 5--9.....................................
Audio Gain 5--10.....................................................
Adjustment Procedures: Digital Section 5--11.......................
Vertical Gain 5-- 11....................................................
Frequency Response 5--12..............................................
VectorGainandX5GainPhase 5--12.....................................
Cable Margin 5--13...................................................
Maintenance
Cleaning 6--1.......................................................
After Repair Adjustments 6--2..........................................
Repackaging Instructions 6--2..........................................
Remove and Replace 6--3.......................................
Tools Required 6--3..................................................
Procedures 6--4......................................................
Top Cover Assembly 6 --5.............................................
LCD Display Assembly 6-- 7...........................................
Top Board Assembly 6-- 15.............................................
Battery Cover Assembly 6-- 25...........................................
Batteries 6-- 28.......................................................
Bottom Cover Assembly 6-- 31..........................................
Troubleshooting Procedures 6--39.................................
Equipment Required 6--39..............................................
Battery-Fault Analysis 6 -- 40............................................
Low-Voltage Power Supply 6--42........................................
Fault Symptom Table 6--43.............................................
Troubleshooting Flowcharts 6--44........................................