No Sound And/Or No Picture On The Rf Modulator (Cinch Works Well); No Lnb Power At All Of The Vertical And Horizontal; Incorrect Lnb Power - Topfield TF4000FI Service Manual

5.2.10. No sound and/or no picture on the RF modulator (Cinch works well)

Possible Cause
1 RF channel is selected
incorrectly.
2 RF modulator
problem.
3. Problem of Audio
Video line on the board.

5.2.11. No LNB power at all of the vertical and horizontal.

Possible Cause
1 'LNB power off
selected in the menu.
2 U3 (LNBP20PD)
related circuit
problem.
3 SMPS has problem.

5.2.12. Incorrect LNB power

Possible Cause
1 If only the 18V is very
low, it can be a SMPS
problem.
2 Both the 18V and 13V
are too low or too high.
How to Check
Check the
selection.
has Replace the RF modulator with
new one. If it works well, it is the
problem of RF modulator.
or Replace the RF modulator with
new one. It will have the same
problem.
How to Check
' is Check the LNB menu.
or Test the Main Board according
has to the advanced function test.
Check the SMPS
How to Check
Check the SMPS(or JP4.2). It
should be higher than 20V.
Test the Main Board according
to the advanced function test.
RF channel Select the correct channel.
Replace it with new one.
Repair the Main Board.
Set the LNB power to ON.
Repair the Main Board according to
the advanced function test.
Replace the SMPS.
If not, replace SMPS.
Repair the main board according to
the advanced function test.
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How to repair
How to repair
How to repair