Daewoo 710B service manual Dynamic Focus, Focus is poor

Page 25

7-1. Dynamic Focus

7-1. Dynamic Focus

		FVH	FVV	Focus is poor
	PHILIPS	: 440V	180V	Focus is poor
	PHILIPS	: 440V	180V
	NEC	: 300V	120V
	SAMSUNG : 300V		120V
			DF
			waveform	Is the
				Is the
	FVH			waveform of the
	FVH		FVV	DF pin in FBT
			FVV	correct?

No

Is the

cathode voltage

of the D575 about 600V?

Yes

*Check after adjusting the static focus finely by VR in FBT

Yes		1. Check the CRT socket
Yes		or connector wire


		2. Trouble in FBT or CRT

No		1. Check the waveform of
		the pin 3 of FBT.
		the pin 3 of FBT.
		2. Check D575

4.5V

2V

0V

	Is the		No
	base voltage of
	the Q751 about
	2.6V?
		Yes


	Is the		No
	waveform of
DF	the pin 10 in IC501

	correct?
waveform

Yes

0.8V

Trouble in Q752, Q753, Q754,

D751, D752, D753, D754,

Q755, Q756

1.Check the 12V DC line.

2.Check Q751,D755

Trouble in IC501 or C520

23

Image 25

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 RemovalDiode Removal/Replacement Power IC, Transistor or Devices Removal/ReplacementTECHNICAL INFORMATION Abbreviations GENERAL INFORMATIONCAUTIONS FOR ADJUSTMENT AND REPAIR PIN CONNECTORCaution For Servicing ADJUSTMENT KEY OPERATION & ADJUSTMENTRECALL ADJUSTMENT PROCESSCONTRAST BRIGHTNESSOSDOn-Screen Display Menu ROTATION Choose different preset color temperatures or set your own customized Self Diagnosis 1. No Character TROUBLESHOOTING HINTSNo 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.U13V DC? of C104 13V DC?8.7V 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 Important Safety Notice REPLACEMENT PARTS LISTAbbreviation of Description PART-CODE CIRCUIT BOARD ELECTRICAL PARTS LISTPART-NAME PART-DESCPART-NAME PART-CODEPART-DESC PART-NAME PART-CODEPART-DESC PART-NAME PART-CODEPART-DESC PART-NAME PART-CODEPART-DESC PART-NAME PART-CODEPART-DESC PART-NAME PART-CODEPART-DESC PART-NAME PART-CODEPART-DESC PART-NAME PART-CODEPART-DESC PART-NAME PART-CODEPART-DESC PART-NAME PART-CODEPART-DESC PART-NAME PART-CODEPART-DESC PART-NAME PART-NAME PART-NAME PART-CODEPART-DESC PART-NAME PART-CODEPART-DESC PART-NAME Serv ce Manual OVERSEAS SERVICE DEPTPRINTED DATE NOV.1998 DAEWOO ELECTRONICS CO