LNB Replacement no signal no quality

[ddoc99]

Folks

I live in a small block where there is a communal dish with a quad LNB attached. This was not installed by sky and yesterday the entire systems went down - no signal, no quality and no lock. One of the neighbours called sky and they confirmed a dead LNB. As the dish was not a sky install they said they could not touch it unless we spent a load of cash.

The dish is 30ft up the side of the building, so not easy to get to, but I managed to remove the old LNB and bought a zinwell JS4 as a replacement.

The dish is solidly installed and I moved absolultely nothing when I removed the old LNB and installed the new one, but still no signal, no quality and no lock.

Any clues?

Is there anything else that could possibly casue such a complete failure?

Thanks, in advance.

[Aves]

If your sky is connected to a wall-plate rather than directly to the dish, then it's likely to be a communal distribution system. If that's the case, chances are that your dish actually uses a Quattro LNB and distribution board, rather than a quad. If this is the case, replacing the LNB with the JS4 won't resolve the issue.

If the dish is solidly fixed, the problem is likely either with the distribution board or the cabling. That being the case the building management company would need to get their contractors out to test and repair the system as Sky are not allowed to touch fixed-site equipment managed by another company.

[ddoc99]

Thanks Aves

Yes, you are correct in that the system is a communal one.

The old LNB was a Manhattan with four outputs, so I assumed that any universla LNB would work.

Do you have any advice on which LNB i should try and purchase?

Many thanks

[Isitme]

I think what Aves meant was that it may not be the LNB that is the problem, it may be the distribution box or some other piece of equipment. You should really get the management company or a trained installer to fix it, but if you still want to have a go, this article from Satcure gives a lot of tips and solid advice.
SatCure LNB fitting instructions

[ddoc99]

Thanks folks

I will look into getting the distribution box and cables looked at.

Many thanks

[MartinP]

But replace the Quattro LNB because the new quad-output LNB won't work with a multiswitch. The fault could be as simple as no mains power to the multiswitch (an RCB tripped?)
LNB mysteries explained

[ddoc99]

The story continues

I managed to get a quattro LNB replacement but as I had plugged in a quad LNB previously, I did not take any notice of how the cables where connected. Now, when I plug in the quattro I have no idea which cable goes where.

What I did do was go back to the distribution board and tried every one of the 24 possible combinations of cables - but without any success.

Is there any technology which could help me identify which output is which from the quattro - remembering that the dish is 30ft up the outside wall and the distribution board in my neighbours loft?

I also assumed that if I had the correct combination I would see a value on the signal strength and quality display of the instalation menu on the TV (or at least my neighbour could see it from his living room).

Any help would be very gratefully recieved.

regards

[MartinP]

Quattro LNBs always have the ports labelled. Absence of labels indicates that it's NOT a Quattro.

Some multiswitches can be used with a quad-output LNB. You need to check the multiswitch to determine what it is.

[ddoc99]

Folks

Thanks for all the help so far.

It now appears (thanks to a friendly sky engineer) that the problem is the multiswitch - and it needs replacing. The only problem is, is that the multiswitch is a Spaun SBK 5501 NFI, which SPAUN no longer make.

Does anyone know of a direct replacement for this device?

regards

David

[Woodster]

The SBK 5501 is a launch amplifier for cascadable systems, and not a multiswitch. It will directly connect to a multiswitch or multiswitches. Because of the way these things work, eg, DC via the terr leg or via the Horizontal IF feeds and whether the DC is from the bottom of the system or injected at the top, a direct replacement from another manufacturer is going to be a mission, but not impossible, and probably expensive. Looking at the spec for the Spaun, it powers from the top down on the IF only, Terr being passive. You could try a Fracarro AMP9254A with an AMP3000 PSU but you will have to bypass the terrestrial with a separate amp of about 25dB gain. You're looking at about £250 - £300ish all in.