Ⅳ. Trouble Shooting; Checking For No Picture - Daewoo DPP-42A1LASB Service Manual

1. Checking for no Picture

A screen doesn't display at all and condition of black pattern or power off.
(1) Check whether the CTRL B/D LED(D1, D2, D3, D4, D5) is turned on or not.
(2) Check the power and signal cable of CTRL B/D.
(3) X B/D, Y B/D, Z B/D is well plugged in.
(4) Check the connection of X B/D, Y B/D and Z B/D to CTRL B/D.
(5) Measure the output wave of X, Y, Z B/D with oscilloscope(more than 200MHz)
and find the trouble of B/D by comparing the output wave with below figure.
- Measure Point fo Y B/D : Bead B39
- Measure Point fo Z B/D : Bead B28
- Measure Point fo X B/D : P3
(6) Check the SCAN(Y side) IC
(7) Check the DATA(X side) TCP IC
(8) Replace the CTRL B/D.
(9) Check the Fuse of Y, Z B/D is open and replace when open.
(10) Check the input voltage. (Vcc=5V/Va=65V/Vs=187V)
Ⅳ. Trouble Shooting
Y B/D Output wave (1frame)
Z B/D Output wave (1frame)
- 9 -