Samsung HPT5044 Series Service Manual page 29

Troubleshooting
No Picture (When audio is normal)
■ ■
Symptom - Audio is normal but no picture is displayed on the screen.
- This may happen when the Main Board is functioning but the X, Y Main Board, Logic Board, or Y Buffer
Boards are not.
Major Checklist
- The output voltage of the Main SMPS.
- This may happen when the LVDS cable connecting the Main Board and the Logic Board is disconnected.
Troubleshooting
Procedures
WHEN SEPARATING AND CONNECTING THE CABLES SUCH AS CN810, CN809, CN808, CN807 OF THE
MAIN SMPS, CN4701 OF THE X MAIN BOARD, AND CN5707 OF THE Y MAIN BOARD, A SPARK MAY BE
Caution
GENERATED BY THE ELECTRIC CHARGE OF THE HIGH CAPACITY CAPACITOR. THEREFORE, WAIT
SOME TIME AFTER DISCONNECTING THE POWER CORD FROM THE UNIT.
4-4
Are the Vs and Va voltages normal after
removing all cables from the SMPS?
(CN810, CN809, CN808, CN807)
Yes
Did problem improve?
Yes
Did problem improve?
Yes
Did problem improve?
Yes
Did problem improve?
CN810
CN809
CN808
CN807
No
Replace the SMPS
No
Replace the Y Main Board
No
Replace the X Main Board
No
Replace the Logic Board
No
Replace the Y Scan Board
Samsung Electronics