Prima PS-42T8 Service Manual page 31

4.4 VGA no picture
Check the horizontal and vertical sync
signal of HS1 and VS1 input of N700.
Check N700 and
periphery circuit
4.5 HDMI no picture
If no picture, check firstly if the set of external device is normal, after eliminating the device problem
still no picture, check X200, N208 and periphery circuit.
4.5.1 Abnormal of the picture:
a. A certain differential wire pair of LVDS (RX0+/-, RX1+/-, RX2+/-, RX3+/-) of X600 is abnormal,
which may lead to lack of color (it's not a complete loss of color).
b. Failure with resistor rows R606~R610, which may lead to loss of corresponding color from the
gray degree corresponding to the picture of all channels.
c. Failure with resistor rows R708~R713, which may lead to loss of corresponding color from the
gray degree corresponding to the picture of VGA/YPRPB/AV/TV channels.
d. Failure with resistor rows R258~R263, which may lead to loss of corresponding color from the
gray degree corresponding to the picture of HDMI channel.
4.5.2 Abnormal picture vertically or horizontally (bar like): Abnormal in complete line extending all
the way from up downward on the screen of stand definition TV set; abnormal vertically on half
screen of high definition TV set. They may be caused by the damage of the address BUFFER
module that directly corresponds to its position, or may be caused by the damage of the connection
wire that directly corresponds to the position of the screen. The horizontal bar like abnormality is
also related to the Y driving circuit that corresponds directly to its position. To judge these
phenomena, It's possible to check it by setting the screen to the status of self check as explained
above
4.5.3 No brightness in the square block area: Normally it's caused by the damage of the address
BUFFER module that directly corresponds to its position, or may be caused by the damage of the
connection wire that directly corresponds to the position of the screen. To judge these phenomena,
it's possible to check it by setting the screen to the state of self-check as explained above.
Check if the input YPRPB
signal is normal.
Yes
Normal Abnormal
The matter of input
interface circuit, N211
and periphery circuit
No
29
Check N700 and
periphery circuit