How To Fix Strong Satellite Receiver With LnbF Error

Lnbf Failed message usually means two things.

1 Short in your RG6 Cable,
2 Blown or failed Tip42C Transistor in the main panel of the receiver.

The problem of some strong receivers is that it kept on displaying error Lnb F  causing no function to the control buttons.

How To Fix This Issue

First Disconnect your RG6 feed from the receiver If the message goes away then you know that is a cable problem.
If message does NOT go away when you disconnect then you know the problem is with the Tip42C Transistor.

First check for Voltage with the components in connection

Need a voltmeter set at DC Volts

With receiver ON you should be getting voltages switching between 13V-18V DC when changing between Vertical and horizontal TP's
.
If no voltage present or only 20V present then most likely you have a blown Tip42c or KA317 transistor.

These unit switches the voltages to your Lnb 13V and 18V

18V = Horizontal TP's
13V = Vertical TP's 

Take the top off your box look on circuit board for a little black transistor ( it has metal top with hole, the heat sink, and three pins on bottom) located about one inch in front of where you hook sat wire.

Make sure you get right replacement part Tip42c or in the case of other decoder products KA317.

The Tip42C is located directly in front of the shiny box that your coaxial cable is connects to.

It is Black and plastic with metal extending above it with a hole in metal and has 3 pin legs which are soldered to the board,

Tip42C or KA317 is printed on the black plastic face.

NTE332 transistor is a direct replacement if you can't find the Tip42C.

Tip42A or Tip42B is for some other strong decoder models, so always check to replace with the right parts for it to work.

Available at most decent electronics stores.

To replace make sure you take note of the way it is oriented,Unscrew from heat sink if one is present, pull out your main board,from the bottom desolder the 3 legs using soldering iron and solder sucker, insert new transistor and resolder, Connect heat sink if one was used originally.