Sony PFM-42X1 Service Manual page 30

4. Regular stripes that correspond to the area of
one or more DATA COF ICs are displayed
1) If the stripes that correspond to the area of one Data
COF IC are displayed regularly, the output from the
output platform of the X B/D has a problem.
If the stripes that correspond to the area of two Data
COF ICs are displayed regularly, the data from the
CTRL B/D is not transmitted correctly.
2) Check if the connection connector of the X B/D that
corresponds to the unusual screen is connected
securely.
3) Replace the corresponding XB/D or CTRL B/D.
Relationship between the screen and X B/D
Screen
Left 4/7 portion of the screen
Right 3/7 portion of the screen
Screen display form
5. The scan FPC has a problem for screen
display.
1) There may be a problem between the Scan FPC and Y
B/D.
2) Check the connection between the Y B/D and Scan
FPC.
3) If the Scan IC has a failure, replace the Y DRV B/D.
Screen display forms
The screen display is very good
The screen display is poor
2-10
X B/D
↔
Right X B/D
↔
Left X B/D
A stripe that corresponds to
one IC may split, or a group of
s t r i p e s m a y b e b u n d l e d
t o g e t h e r a n d d i s p l aye d o n
another part of the screen.
One eighth of screen
Checking method of SCAN IC
Change the Vpp pin into ANODE and GND pin into
CATHODE, and then test the diode in the forward or
backward direction.
6. The screen has vertical lines with a regular
gap. (A vertical stripe flashes in a specific
color)
1) The control B/D has a problem.
2) Replace the control B/D.
Screen display form
The screen shows vertical
lines with a regular gap
7. A data copy occurs in the vertical direction.
1) This is due to the incorrect marking of a scan wave.
2) Replace the Y DRV B/D or Y SUS B/D.
Screen display forms
Display Pattern
Case 2 : Top Copy Case 3 : Bottom Copy
Case 1 : Entire Copy
Case 4 : Entire Copy
PFM-42X1/42X1N