Daewoo 710B service manual Troubleshooting Hints, No Character

Page 17

TROUBLESHOOTING HINTS

TROUBLESHOOTING HINTS

1. No Character

No Character

Are the

No

Contrast &

Brightness Controls

maximum

Yes

Is whole

No

screen bright?

Yes

Is CRT

Yes

Cathode (Rk, Gk, Bk)

signal level

Rk, Gk, Bk

normal?

No

About 45Vpp

Is the

output signal of the

Yes

(pin 21, 24, 26) pre-amp

(IC801, KA2500)

normal?

No

Change the Contrast & Brightness control to maximum

	No Raster	Refer to
	No Raster	No Raster
		No Raster

Check the peripheral circuit of CRT Board

Check the video output circuit and IC803 (pin 1, 3, 5) and their ambient circuit

Is 12V DC line			No
normal?
	Yes
	Yes

Is clamping			No
pulse (pin 18 of IC801)
pulse (pin 18 of IC801)
normal?
	Yes
	Yes
			No
Is input signal			No
normal?
	Yes
	Yes


Trouble in IC801 and
its ambient circuit

Trouble in 12V DC line of the Main PWB

Check the clamping pulse circuit

Check the signal cable

15

Image 17

Contents XGA COLOR MONITOR Model 710B Service ManualCONTENTS Safety Check SAFETY PRECAUTIONSFire & Shock Hazard Implosion ProtectionSymbols in the manual GENERAL SAFETY INFORMATIONSymbols as marked on equipment Terms in the manualGeneral Servicing Precautions SERVICING PRECAUTIONSGeneral Soldering Guidelines Electrostatically Sensitive ES DevicesReplacement IC Removal/Replacement“Small-Signal” Discrete Transistor Removal/Replacement RemovalTECHNICAL INFORMATION Power IC, Transistor or Devices Removal/ReplacementDiode Removal/Replacement Abbreviations GENERAL INFORMATIONCaution For Servicing PIN CONNECTORCAUTIONS FOR ADJUSTMENT AND REPAIR ADJUSTMENT KEY OPERATION & ADJUSTMENTRECALL ADJUSTMENT PROCESSCONTRAST BRIGHTNESSOSDOn-Screen Display Menu ROTATION Choose different preset color temperatures or set your own customized Self Diagnosis No Character TROUBLESHOOTING HINTS1. No Character No Raster 2. No RasterOne color is missing 3. A missing ColorAbnormal OSD Font 4. Abnormal OSD FontTrouble in Horizontal output circuit No Raster 5. Horizontal Output CircuitIs H.Sync Unstable pictureinput pin of IC501 correct?Unstable or Abnormal picture 6-2. V.OSC/Deflection CircuitMonitor remains unfocused 7. FocusFocus is poor 7-1. Dynamic FocusPoor convergence 8. ConvergenceAbnormal H.Size 9. Abnormal Picture 9-1. Horizontal Sizechanged, is the H.size changed? 1.Check B+ section of TDA9109 and its ambient circuitAbnormal V.Size 9-2. Vertical SizeTrouble in H.V circuit No Raster 10. High Voltage CircuitSide-Pincusion distortion is excessive or barrel 11. Side-Pincushion CircuitTrouble in P.S.U 12. Power Supply Unit P.S.U8.7V DC? of C104 13V DC?13V DC? Standard Adjustment Conditions ALIGNMENT PROCEDUREPre-Adjustment Main Adjustmentl Repeat e,f,g,h,i,j DIAGRAM Main PCB Component Side PCB LAYOUTMain PCB Solder Side Video PCB Component Side Video PCB Solder Side Page EXPLODED VIEW DIAGRAM Abbreviation of Description REPLACEMENT PARTS LISTImportant Safety Notice PART-CODE CIRCUIT BOARD ELECTRICAL PARTS LISTPART-NAME PART-DESCPART-DESC PART-CODEPART-NAME PART-DESC PART-CODEPART-NAME PART-DESC PART-CODEPART-NAME PART-DESC PART-CODEPART-NAME PART-DESC PART-CODEPART-NAME PART-DESC PART-CODEPART-NAME PART-DESC PART-CODEPART-NAME PART-DESC PART-CODEPART-NAME PART-DESC PART-CODEPART-NAME PART-DESC PART-CODEPART-NAME PART-DESC PART-CODEPART-NAME PART-DESC PART-NAME PART-DESC PART-CODEPART-NAME PART-DESC PART-CODEPART-NAME PART-DESC Serv ce Manual OVERSEAS SERVICE DEPTPRINTED DATE NOV.1998 DAEWOO ELECTRONICS CO