Flashing Or Constant LNB-F Displayed On The Front Panel

Flashing Or Constant LNB-F Displayed On The Front Panel Flashing Or Constant LNB-F Displayed On The Front Panel

Constant LNB-F is usually due to a Blown Tip42C Transistor on the main Board.

CNX power on but the front panel flashing LNBF. Sometimes it has signal then quit

If you have some basic soldering and de-soldering skills you can fix it yourself.

-----------Here are the directions for repairing.----------

First check for Voltage at sat in connection

Need a voltmeter set at DC Volts

Connect a short piece of coax to the Sat IN connector and check for voltage between centre copper and the screw connector.

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 transistor.

This unit switches the voltages to your LNB 13V and 18V

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

When it fails you will either get No Voltage showing at your Sat In connector or it will lock at 20Volts and not switch to 13V.

If it is locked at 20Volts you will only be able to get Horizontal TP's on your STB

If it is locked at 13V then you will only receive Vertical TP's.

If no voltage present then you will get No Signal Message

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.
It's NOT the one attached to a large aluminum heatsink.

Make sure you get right one, part Tip42c.

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

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

Tip42C is printed on the black plastic face.

Viewsat ultra's and CNX Receivers use the Fairchild KA317 Transistor and it is Mounted to a Heatsink

Take note of the way it is oriented, if mounted backwards it will not work.

If you are getting NO Signal Message and have No Voltage at your Sat In Connector Hook up sat wire and take a small screwdriver and touch first two pins toward back of box together.

If you get a signal, then this transistor is bad and should be replaced.

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

Tip42A or Tip42B will not work.

It has to be Tip42C or NTE332

The NTE332 is more robust and worth the extra $.

Available at most decent electronics stores.

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