Troubleshooting; Checking For No Picture - Sony PFM-42X1 Service Manual

2-4. Troubleshooting

2-4-1. Checking for No Picture

Check the following points if the monitor shows the Full Black pattern or the power is off and no picture
appears on screen.
1) Check whether the CTRL B/D LED (D10, D11, D12, D13, D17) is turned on or not.
2) Check the power and signal cable of the CTRL B/D.
3) Check whether the X B/D, Y B/D, and Z B/D are plugged securely.
4) Check the connection of the X B/D, Y B/D and Z B/D to the CTRL B/D.
5) Measure the output wave of the X, Y, and Z B/D with the oscilloscope (200 MHz or more) and check
if there is any problem on the boards by comparing the output wave with the following figure.
. Measurement point for the Y B/D : TP (Bead B50)
. Measurement point for the Z B/D : TP (Bead B35)
. Measurement point for the X B/D : COF TP
6) Check the SCAN (Y side) IC.
7) Check the DATA (X side) COF IC.
8) Replace the CTRL B/D.
PFM-42X1/42X1N
<A: Y B/D Output wave - 1 FRAME>
<B: Y B/D Output wave - 1 SF>
<A: Y B/D Output wave - 1 FRAME>
<B: Y B/D Output wave - 2,4 to 12 SF>
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