LNB Functionality? - Canadian TV, Computing and Home Theatre Forums

fifight · 2010-03-08, 12:46 PM

How do you test an LNB to see if it is working OK?

It is an older dual input that was on a 18" dish.
Bell took it down when they put in a new dish. I'm trying to reinstall it, but no signal to a 5200 dual tuner.
I think they may have been dropped off the roof.

despe666 · 2010-03-08, 04:00 PM

The easiest way would be to install it on a dish that you know for sure is well aligned. Otherwise, I can't think of any other way to test it.

Pinza · 2010-03-08, 04:06 PM

Just ensure that you have a line connected to the relevant Tuner when it the Signal Strength Screen.

I have seen people fight for hours not getting a signal only to discover that the RG6 was connected to Tuner #1 and the Screen was showing Tuner #2......

WillDekkard · 2010-03-09, 01:38 AM

How to check your LNBs - there is a way to check the LNB with it off. (You will need a multi-meter & alligator clips)(You will need to strip back 2 coax cables with F connectors on each)

For Standard Dual LNBs:
1) first strip off the coax cable until the cable copper is exposed, then wind the grounds cable threads together so you can attach claps to them both.
2) secondly check to see if ground, to copper 13volts, then swap them copper to, ground 17volts, if you get a singal on both the LNB is OK, if not and not voltage on one side of the Legacy LNB then its bad.

Pinza · 2010-03-09, 06:47 AM

Just exactly where is this voltage going to come from if the LNBF is OFF.?

fifight · 2010-03-09, 01:39 PM

Unfortunately, I don't know if the dish is aligned properly. I have ordered a strength meter and continuity tester off eBay.

Thanks for your reply.

fifight · 2010-03-09, 01:40 PM

I have been going thru a 3X4 switch that someone advised me may be fried. I will try going straigh to the tuner.

fifight · 2010-03-09, 01:41 PM

Thanks for the reply.
I will try a couple of other things first.

WillDekkard · 2010-03-14, 03:00 AM

Quote:

Originally Posted by Pinza

Just exactly where is this voltage going to come from if the LNBF is OFF.?

From the 1.5V battery in the multimeter. I have tested many LNBs in this manner using the ohm meter. Tested known "fried" LNBs and new or working LNBs before testing suspect ones.

Pinza · 2010-03-14, 10:21 AM

You have a magic meter then.....lol

with its 1.5 volt battery it generates 18 volt supply.?....lol

ScaryBob · 2010-03-14, 01:04 PM

I agree. This will not work on an LNB. The 14v and 18v DC levels are present on switch and receiver inputs. They are used by the LNB for operating power and to switch between transponders. LNBs do not generate any DC voltages. The multimeter voltage level reading is a good test for switches and receivers when half the transponders are missing. I repeat, it will not work on disconnected LNBs.

WillDekkard · 2010-03-15, 02:27 AM

If the LNB is fried, it is fried and will not allow any voltage through. No need to test with 13-18Volts, only the continuity.

2010-03-09, 01:38 AM	#4
WillDekkard Join Date: Nov 2008 Location: Off World Colony Posts: 57	How to test a LNB How to check your LNBs - there is a way to check the LNB with it off. (You will need a multi-meter & alligator clips)(You will need to strip back 2 coax cables with F connectors on each) For Standard Dual LNBs: 1) first strip off the coax cable until the cable copper is exposed, then wind the grounds cable threads together so you can attach claps to them both. 2) secondly check to see if ground, to copper 13volts, then swap them copper to, ground 17volts, if you get a singal on both the LNB is OK, if not and not voltage on one side of the Legacy LNB then its bad.

2010-03-14, 01:04 PM	#11
ScaryBob Veteran Join Date: Feb 2009 Location: The Dandelion City Posts: 7,133	I agree. This will not work on an LNB. The 14v and 18v DC levels are present on switch and receiver inputs. They are used by the LNB for operating power and to switch between transponders. LNBs do not generate any DC voltages. The multimeter voltage level reading is a good test for switches and receivers when half the transponders are missing. I repeat, it will not work on disconnected LNBs. __________________ At 20 I had a good mind. At 40 I had money. At 60 I've lost my mind and my money. Oh, to be 20 again. --Scary

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

2010-03-08, 12:46 PM	#1
fifight Rookie Join Date: Mar 2010 Posts: 4	LNB Functionality? How do you test an LNB to see if it is working OK? It is an older dual input that was on a 18" dish. Bell took it down when they put in a new dish. I'm trying to reinstall it, but no signal to a 5200 dual tuner. I think they may have been dropped off the roof.

2010-03-08, 04:00 PM	#2
despe666 Join Date: Nov 2005 Posts: 147	The easiest way would be to install it on a dish that you know for sure is well aligned. Otherwise, I can't think of any other way to test it.

2010-03-08, 04:06 PM	#3
Pinza Veteran Join Date: Jul 2008 Location: GTA Posts: 8,582	Just ensure that you have a line connected to the relevant Tuner when it the Signal Strength Screen. I have seen people fight for hours not getting a signal only to discover that the RG6 was connected to Tuner #1 and the Screen was showing Tuner #2......

2010-03-09, 06:47 AM	#5
Pinza Veteran Join Date: Jul 2008 Location: GTA Posts: 8,582	Just exactly where is this voltage going to come from if the LNBF is OFF.?

2010-03-09, 01:39 PM	#6
fifight Rookie Join Date: Mar 2010 Posts: 4	Unfortunately, I don't know if the dish is aligned properly. I have ordered a strength meter and continuity tester off eBay. Thanks for your reply.

2010-03-09, 01:40 PM	#7
fifight Rookie Join Date: Mar 2010 Posts: 4	I have been going thru a 3X4 switch that someone advised me may be fried. I will try going straigh to the tuner.

2010-03-09, 01:41 PM	#8
fifight Rookie Join Date: Mar 2010 Posts: 4	Thanks for the reply. I will try a couple of other things first.

2010-03-14, 10:21 AM	#10
Pinza Veteran Join Date: Jul 2008 Location: GTA Posts: 8,582	You have a magic meter then.....lol with its 1.5 volt battery it generates 18 volt supply.?....lol

2010-03-15, 02:27 AM	#12
WillDekkard Join Date: Nov 2008 Location: Off World Colony Posts: 57	If the LNB is fried, it is fried and will not allow any voltage through. No need to test with 13-18Volts, only the continuity.