Attenuator blows up 2 Freesat boxes

J

joddle

Specialist Contributor
Messages
517
My Satellite Setup
2x Pace 2600 C1 (in a box just in case) , 3 x Humax HD Foxstat (2 of which in store as spares) . 3x Manhatten Plaza - Pasat 2.4 PF dish mounted on flat roof with Invacom C120 quad LNB .
My Location
Massanassa, Valencia, Spain
Agg - and just before Christmas - sitting watching Freesat on my little Manhatten HD then all of a sudden it stops - no apparent reason but no output - box lights up OK and seems to respond to the remote but simply nothing coming out at all. Never mind, I have an old Humax Freesat HD at hand so plug it in and all seems to be up and running again - but a few days later that one to starts to have problems - first bad breakup then total no signal - but after a few seconds then comes up the message "LNB short".

I unplug the feed and check - no short there - but then think perhaps the in line adjustable attenuator is shorting - and that indeed was the problem. Attenuator now in the bin.

The Manhatten does not do anything but the Humax wants to do something but cannot - it simply can't find a sat signal so I presume the LNB short has done damage to the LNB power feed but before I toss the box in the bin thought I would ask here if this is a reparable thing or is it indeed a dead duck.

Luckily I still have 2 of my trusty old Pace 2600 boxes so we won't be without UK TV over Christmas and they don't need the attenuator anyway. Just a shame the Manhatten did not exhibit an LNB short message as that would have prompted me to be more careful before connecting up the Humax!
 
Lazarus

Lazarus

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Sorry to hear this.

But I'm surprised neither box has effective short-circuit protection for the LNB supply.
 
J

joddle

Specialist Contributor
Messages
517
My Satellite Setup
2x Pace 2600 C1 (in a box just in case) , 3 x Humax HD Foxstat (2 of which in store as spares) . 3x Manhatten Plaza - Pasat 2.4 PF dish mounted on flat roof with Invacom C120 quad LNB .
My Location
Massanassa, Valencia, Spain
Sorry to hear this.

But I'm surprised neither box has effective short-circuit protection for the LNB supply.
Me too!!!! There is a smell of a flashover from the inside - a bit like the smell you get when playing with an electric trainset.
 
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J

joddle

Specialist Contributor
Messages
517
My Satellite Setup
2x Pace 2600 C1 (in a box just in case) , 3 x Humax HD Foxstat (2 of which in store as spares) . 3x Manhatten Plaza - Pasat 2.4 PF dish mounted on flat roof with Invacom C120 quad LNB .
My Location
Massanassa, Valencia, Spain
Just opened up the box - when its first turned on it seems to find a sat then I hear some arcing but cant see it on the LNB board and then nothing. May try and get a scrap box and swap the lnb board as mine has had the power supply upgraded already. Already found another box on fleabay so it will do as a spare anyway as we have the same box in a holiday let so need one available in case of any issues there.
 
A

archive10

Guest
Just before you start rearranging the innards of your boxes: You are of course sure it's not the LNB?
Have you tried the Pace's yet?
 
Channel Hopper

Channel Hopper

Suffering fools, so you don't have to.
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A little less analogue, and a lot more crap.
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Just before you start rearranging the innards of your boxes: You are of course sure it's not the LNB?

Or carbonising of the cable inside one of the f-plugs ?
Have you tried the Pace's yet?
No need to get suicidal .
 
woborny

woborny

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My Satellite Setup
1.8m Dish, most Sky and Freesat receivers, 80cm on Illusion motor and Dreambox DM7025, TDT, TDT HD, Ariva 100e,
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Gandia, 70kms south of Valencia, Spain
Check you cabling. Have found that installs about 10 years or so old where cable has been in the spanish sun for that time has started to crack... and with the small bit of rain we had last weekend, have been to a few people whose systems had gone due to water shorting inb the cabling...
 
J

joddle

Specialist Contributor
Messages
517
My Satellite Setup
2x Pace 2600 C1 (in a box just in case) , 3 x Humax HD Foxstat (2 of which in store as spares) . 3x Manhatten Plaza - Pasat 2.4 PF dish mounted on flat roof with Invacom C120 quad LNB .
My Location
Massanassa, Valencia, Spain
Have checked everything - no shorts on the feed or LNB - checked with multimeter and waggled the cable about in case movement set it of but nothing. - the feed is fine and working well on the Pace and the other Manhatten with full SS and SQ - no carbonising on the plugs etc - no cracking of the cable either - there was however a sound of arcing from inside the Humax so I presume something has died in there. I checked the attenuator also with the MM and it was that which was shorting - can't do anymore tests as its now in the bin but did notice the adjustment screw seemed to be very flimsy and turned more than it should so looks like it failed mechanically inside. We will never know though!
 
J

joddle

Specialist Contributor
Messages
517
My Satellite Setup
2x Pace 2600 C1 (in a box just in case) , 3 x Humax HD Foxstat (2 of which in store as spares) . 3x Manhatten Plaza - Pasat 2.4 PF dish mounted on flat roof with Invacom C120 quad LNB .
My Location
Massanassa, Valencia, Spain
OMG - lost another box yesterday - Humax Foxsat HD - this time it was running perfectly then suddenly LNB nothing - no sat signal at first so thought just an outage but realised wrong time. Checked cable connection and powered up again and got the LNB short notice - and along with that the smell or arcing from inside. No trace of damp though no water in the box and cable checks out with multi-meter - so attached another Foxsat HD and all fine again - Tried the box on another feed and it does not work properly and the smell or arcing remains. Now really worried it is the cable but can't see any damage at all on it and the rubber gaiter on the LNB is very tight and not perished - Don't really want to redo the cable as it is part built in and replacing it means chiselling out a groove in one of my walls or the cable will be seen running down the inside of the sitting room wall and a certain person would not allow that!!!
 
Lazarus

Lazarus

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Much else.
My Location
North York Moors
Oh dear. I really hope you get to the bottom of this.
 
PaulR

PaulR

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Can you run a new section of cable even if it will be on show? Usual platitudes about it being temporary of course!

If the problem goes away then you know that the old cable is faulty somewhere and when you eventually get around to digging it out you can laid in some flexible conduit to run the new cable inside.
 
Channel Hopper

Channel Hopper

Suffering fools, so you don't have to.
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A little less analogue, and a lot more crap.
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UK South
Are you certain it's not a supply power surge ?

Humax machines of old used to have a cable short indicator that would shut down the tuner to protect the innards.
 
J

joddle

Specialist Contributor
Messages
517
My Satellite Setup
2x Pace 2600 C1 (in a box just in case) , 3 x Humax HD Foxstat (2 of which in store as spares) . 3x Manhatten Plaza - Pasat 2.4 PF dish mounted on flat roof with Invacom C120 quad LNB .
My Location
Massanassa, Valencia, Spain
Agggg - should have gone to Specsavers - I did an inch by inch inspection of the this morning of the whole feed and found a small section only an inch or so where the plastic has perished and exposed the braiding - It seems after all that water was the most likely cause of all the failures as the evening before it failed we had a pretty heavy rainstorm - and thinking back, the last time it failed was also just after heavy rain. Should have looked closer then!!! . Its pretty amazing that 99% of the cable looks fine and the plastic seems perfect - however on this one little area it has failed pretty radically. Thinking more about it I realised that that particular feed was using cable installed for 2d and well before the rest of the system so could be 12 or more years old.

Well that's the job for the weekend sorted - a new cable albeit I am not going to remove the final 2m of cable which is buried in the wall but use an f plug connector as it will be well under cover and away from damp and direct sunlight. With my old 2d 2.4 dish here in Valencia I am not expecting any reception issues due to a slightly degraded signal from the joint. Thanks everyone for your suggestions and yet again Woborny was absolutely correct.
 
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PaulR

PaulR

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Wirral, NW UK and Vaucluse, France.
I really wouldn't use the section of cable buried in the wall at all as you need to eliminate (or prove) the whole length of old cable as the source of the problem. Sod's Law dictates that the bit of cable you can't see will be the bit that's the problem.
 
J

joddle

Specialist Contributor
Messages
517
My Satellite Setup
2x Pace 2600 C1 (in a box just in case) , 3 x Humax HD Foxstat (2 of which in store as spares) . 3x Manhatten Plaza - Pasat 2.4 PF dish mounted on flat roof with Invacom C120 quad LNB .
My Location
Massanassa, Valencia, Spain
I really wouldn't use the section of cable buried in the wall at all as you need to eliminate (or prove) the whole length of old cable as the source of the problem. Sod's Law dictates that the bit of cable you can't see will be the bit that's the problem.
Maybe but that part of the cable seems fine and at the moment I don't want to have a re-plastering job in the lounge. I have however left enough cable coiled up to complete the job at a later date if I get the inclination. Already with the new cable in place (apart from the final 1.5M and a crude joint in it) the signal is much improved over what it was before with SS and SQ almost 100% on almost all channels! Only Yesterday and its group show a low SQ and before I could not even get them!

Looking at the pic attached I think that was the real cause of the problem - in 25M of cable its the only bit that seems to have failed!!! Anyway good job for now. Now to inspect/change the other feeds as 2 of them are now 8 years old and maybe will also fail soon!!!!
 

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PaulR

PaulR

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Was that split inside or outside the house? If outside was it somewhere that could be affected by water ingress?

Or was it possibly somewhere that could brush against something metal in a wind?
 
Lazarus

Lazarus

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My Satellite Setup
80cm Motorised.
Several small Dishes.
Much else.
My Location
North York Moors
Nice work, @joddle
 
J

joddle

Specialist Contributor
Messages
517
My Satellite Setup
2x Pace 2600 C1 (in a box just in case) , 3 x Humax HD Foxstat (2 of which in store as spares) . 3x Manhatten Plaza - Pasat 2.4 PF dish mounted on flat roof with Invacom C120 quad LNB .
My Location
Massanassa, Valencia, Spain
Was that split inside or outside the house? If outside was it somewhere that could be affected by water ingress? Or was it possibly somewhere that could brush against something metal in a wind?
It was hanging in a cable stay on a well exposed area (sun all day) but also on a corner where the cable bends round a bit - maybe that weakened the casing which split once it had too much sun:

On the plus side, having really confirmed it was water ingress - I decided to get the broken Humax out and took it apart - wiped over all the PCBS then used a hair dryer to ensure there was no possibility of any damp or water left on the tracks - plugged it in and hey presto - works like new again and no arcing :) Now to see if the other box can be recovered in the same way: Alas the little Manhatten is already in the scrap heap in the sky but maybe that would have been OK too - Ah well - you live and learn eh!
 
PaulR

PaulR

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My Satellite Setup
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Indeed. I've never had it happen to me but I've read of cable getting so waterlogged that when the F plug was unscrewed from the back of the receiver water dripped out.
 
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