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Monday, 24 October 2016

VU+ DUO repair: fixed tuner problems!

I have several satellite dishes, but two are special: a 100cm with multi feed and a 80cm with just one LNB. The cables go down to a multi switch and from there one cable to each of 8 rooms.

In the past, the multi switch got broken (the power source literally burned) and was repaired, but over the years I started to struggle with corrosion on the cables on the roof. More precisely, the cables come from the LNB and attach to the cable going down by means of an F-type male-male connector. This connector gets corroded and after some years/month, needs to be replaced and the corroded part of the cable must be cut off. This annoys me a lot, because the length of the installed cable going down to the distribution box is getting shorter every year.

This whole thing started of wrong: when I was building the house, I wanted to go cheap and imagined having the multi switch on the roof. Hence I only passed down 8 cables. After two multi switches breaking down due to humidity, rain, sun, heat, cold, etc., I accepted that the multi switch really needed to go inside the house. Naturally it was protected in a box, but it was not ventilated and, well, it did not work. One of the drawback was that I only had a total of 9 cables, which meant that I could only pass the signal of two satellites (19.2E + 13.0E) and one band of the third satellite (30.0W), when originally it was planned to have 19.2E, 13.0E, 30.0W and 28.2E.

Also, this is why I ended up with too short cables on the roof and the requirement to use the F-type male-male connector.

Because I have other dishes, two of which are motorized, and all of them go to my shack, where I pass my time messing around with TV, CATV and SAT equipment, I haven't lately bothered to fix the fact that in the bedroom I wasn't really receiving anything anymore. I have been spending awake time using a tablet instead.

Anyway, this weekend I decided to sort this out once for all. I went to the roof and replaced the QUADRO-LNB's with QUATTRO-LNB's and redone all the cables. I put a simple DiSEqC-1.0 switch and used a single cable to the bedroom. I wasn't using SAT on any other TV anyway. Also, this solution gives me the option to pass SAT to 3 further rooms. I removed the multi switch, which was at the end of its life cycle, anyway.

When I finally tested the now full 4 satellites in the bedroom: nothing!
Still no reception... :(

Could I have a fault in any cable? Up to the roof, replaced one cable I had reused from the previously installed ones.

Tested again: nothing.

Took on of my TV analysers and checked: all OK. Could the TV analyser have a much more sensitive tuner?

Weird!

Took another SAT receiver (AZBox Ultra HD) and...
...got 3800 channels.

So after all, the culprit had to be the VU+ DUO sat receiver, which I have for some 4-6 years.

I did a full RESET and got about 500 channels. Far too few, but everything else was working fine.

Started reading in the forums and found out that this is a common problem: missing the High-Band/Horizontal channels, due to dried capacitor! This causes the required 16V for upper band channels to not be generated properly.

*** Repair starts here ***

Changed a 100uF capacitor (C852) and... nothing.
Changed two 1000uF capacitors (C848 and C819) and... IT WORKED AGAIN!

*** Repair ends here ***

Conclusion:
  • Spend 1 day on the roof for nothing.
  • Changing the whole SAT reception distribution for nothing (OK: now I have 4 full satellites, in one room, with option for a total of 4 rooms, instead of having 2+1 satellites in 8 rooms).
  • Did a repair in 1 hour (can be reproduced now in about 15 minutes), with a total cost of 3 capacitors worth 1.20 Euro.

TODO:

I will now buy a complete set of capacitors and replace them all. It was sheer luck to have the 100uF and 1000uF capacitors lying around, but I did not have enough of them and i lack the 220uF ones, too.

Also, the ones I used are fairly old and probably sub-standard, so they will be replaced again.

Anyway, that saved me from having to buy a new VU+ receiver (they are really good products).

Regards,
Vitor


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