Topfield TF4000FI, Руководство по обслуживанию, Страница: 12 / 62

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5.2.10. No sound and/or no picture on the RF modulator (Cinch works well)
Possible Cause How to Check How to repair
1 RF channel is selected
incorrectly. Check the RF channel
selection. Select the correct channel.
2 RF modulator has
problem.
Replace the RF modulator with
new one. If it works well, it is the
problem of RF modulator. Replace it with new one.
3. Problem of Audio or
Video line on the board.
Replace the RF modulator with
new one. It will have the same
problem. Repair the Main Board.
5.2.11. No LNB power at all of the vertical and horizontal.
Possible Cause How to Check How to repair
1 ‘LNB power off ‘ is
selected in the menu.
Check the LNB menu. Set the LNB power to ON.
2 U3 (LNBP20PD) or
related circuit has
problem.
Test the Main Board according
to the advanced function test. Repair the Main Board according to
the advanced function test.
3 SMPS has problem. Check the SMPS Replace the SMPS.
5.2.12. Incorrect LNB power
Possible Cause How to Check How to repair
1 If only the 18V is very
low, it can be a SMPS
problem. Check the SMPS(or JP4.2). It
should be higher than 20V. If not, replace SMPS.
2 Both the 18V and 13V
are too low or too high. Test the Main Board according
to the advanced function test. Repair the main board according to
the advanced function test.