How to check an LNB for faults?

Geerdub · 13-02-11, 11:53 PM

Hi,

I have had two humax boxes die in a row. Before I plug the third one into the system I want to be 100% sure that I am just very unlucky and confirm that there is nothing wrong with the set up or lnb.

What is the best way of testing an lnb? Have tested for shorts at the sockets and get about 5Mohm. sound ok? What else can I check?

Cheers

pedro2000uk · 14-02-11, 02:11 PM

Quote:

Originally Posted by Geerdub

..... What else can I check?

also check any of your media gear it's connected to for stray voltage faults etc..

Geerdub · 14-02-11, 02:17 PM

Cheers Pedro,

The only other connection apart form the LNB is the HDMI cable to the 6 Series 6 Samsung LEDtv.

I did notice when the second humax died that the back of the box felt tingly to the touch

and this went away when I pulled the HDMI....

Does that make sense that there could be stray voltage from the TV killing the Humax?

Fualty TV- Faulty HDMI cable? Whats best way to check? Get a pinout for an HDMI cable and check voltages?

Many thanks

Geerdub · 14-02-11, 07:41 PM

Right, further investigation shows 45vac on standby and 60vac potential between tv case (and hdmi shield) and house ground.

That does not seem right! Warranty call to Samsung I think.

Pretty sure Rhys what could have killed the humax. Any thoughts on this anyone?

Geerdub · 14-02-11, 07:42 PM

Dunno who Rhys is! Bloody iPhone auto spelling!

pedro2000uk · 14-02-11, 08:26 PM

Does it say anything in the Humax manual about whether it has to be earthed, even though it has a no earth lead/plug? Does the flat screen have an earthed mains lead/plug.

Geerdub · 14-02-11, 08:39 PM

Curiously the label on the humax lead says "This appliance must be earthed" even though the cable looks like twin only. Has metal earth pin. This is a pre wired and permanently attached lead.

Samsung tv is a figure 8 kettle lead ( definitely no earth).

Could this measurement just be a crazy ground loop?

kerrywez · 14-02-11, 10:20 PM

The HDMI lead does carry a charge, but it should only be DC and very small, something like a USB does. If I were you I would give Sammy a call and ask what the score is and let them know that you have burnt two Humy boxes and do not want to burn another one.

Regards Wez

Geerdub · 14-02-11, 10:29 PM

Cheers Wez.

Will call them in the morning and see what they say.

13-02-11, 11:53 PM	#1 (permalink)
Geerdub Junior Member Join Date: Feb 2011 Posts: 6	How to check an LNB for faults? Hi, I have had two humax boxes die in a row. Before I plug the third one into the system I want to be 100% sure that I am just very unlucky and confirm that there is nothing wrong with the set up or lnb. What is the best way of testing an lnb? Have tested for shorts at the sockets and get about 5Mohm. sound ok? What else can I check? Cheers

14-02-11, 02:17 PM	#3 (permalink)
Geerdub Junior Member Join Date: Feb 2011 Posts: 6	Re: How to check an LNB for faults? Cheers Pedro, The only other connection apart form the LNB is the HDMI cable to the 6 Series 6 Samsung LEDtv. I did notice when the second humax died that the back of the box felt tingly to the touch and this went away when I pulled the HDMI.... Does that make sense that there could be stray voltage from the TV killing the Humax? Fualty TV- Faulty HDMI cable? Whats best way to check? Get a pinout for an HDMI cable and check voltages? Many thanks

14-02-11, 07:41 PM	#4 (permalink)
Geerdub Junior Member Join Date: Feb 2011 Posts: 6	Re: How to check an LNB for faults? Right, further investigation shows 45vac on standby and 60vac potential between tv case (and hdmi shield) and house ground. That does not seem right! Warranty call to Samsung I think. Pretty sure Rhys what could have killed the humax. Any thoughts on this anyone?

14-02-11, 07:42 PM	#5 (permalink)
Geerdub Junior Member Join Date: Feb 2011 Posts: 6	Re: How to check an LNB for faults? Dunno who Rhys is! Bloody iPhone auto spelling!

14-02-11, 08:26 PM	#6 (permalink)
pedro2000uk Installer/Design Engineer Join Date: Jun 2009 Location: Cheshire Posts: 369	Re: How to check an LNB for faults? Does it say anything in the Humax manual about whether it has to be earthed, even though it has a no earth lead/plug? Does the flat screen have an earthed mains lead/plug. __________________ *..Satellite Installer-.. Cheshire/ Manchester/ Staffs/ Derbyshire/ N Wales/ Shrops/ Yorks/ Notts...motorised & fixed,* small, medium & BIG

14-02-11, 08:39 PM	#7 (permalink)
Geerdub Junior Member Join Date: Feb 2011 Posts: 6	Re: How to check an LNB for faults? Curiously the label on the humax lead says "This appliance must be earthed" even though the cable looks like twin only. Has metal earth pin. This is a pre wired and permanently attached lead. Samsung tv is a figure 8 kettle lead ( definitely no earth). Could this measurement just be a crazy ground loop?

14-02-11, 10:20 PM	#8 (permalink)
kerrywez Grumpy Old Sat Man Join Date: Sep 2007 Location: Co. Kerry, Ireland Posts: 2,471	Re: How to check an LNB for faults? The HDMI lead does carry a charge, but it should only be DC and very small, something like a USB does. If I were you I would give Sammy a call and ask what the score is and let them know that you have burnt two Humy boxes and do not want to burn another one. Regards Wez __________________ Dreambox 7025, 250HDD, Dreambox 500s, 110 X 90Cm Hirschmann on Clarketech rotor, 1.2 Mtr. Channel Master. AZBox HD Running on E2. TM6900 super combo.

14-02-11, 10:29 PM	#9 (permalink)
Geerdub Junior Member Join Date: Feb 2011 Posts: 6	Re: How to check an LNB for faults? Cheers Wez. Will call them in the morning and see what they say.

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