Need some input on this

Huevos

Huevos

Satellite Freak
Messages
5,994
My Satellite Setup
57E to 58W, C-band and Ku, DVB-S2, 4:2:2 and blindscan.
My Location
38.5ºN, 0.5ºW
A guy called me, no signal on Astra 2D, but working on all other sats/channels (2D is low signal here). I went there, plugged in the meter and there was plenty of signal for 2D reception up to the box, so I changed the box (from a Pace 430N to a Pace 430N). Anyway the same fault has developed on the second box over a couple of days so today I went back again and the new box has "gone deaf". There's well over 9dB carrier to noise at the receiver end of the cable on 2D and a third box seems to work fine. What could be damaging these receivers? I've got a few ideas but I'd like some input before posting them so I don't taint anyone's vision. Thanks for any input.

P.S. I've posted here rather than in the 28E section as this seems more likely to be a general technical fault, not a 28E peculiarity.
 
Lazarus

Lazarus

Tout Rond Bon Oeuf
Staff member
Messages
25,576
My Satellite Setup
80cm Motorised.
Several small Dishes.
Much else.
My Location
North York Moors
Well I can't suggest what it might be, because the DS430N, as well as being sensitive, has proved pretty darned bulletproof over the last five years or so.

So whatever the cause is, it seems likely it is something external which is having an effect - although I should have thought that the input circuitry would be overload protected and the LNB supply/switching pretty armour plated too.

Something nasty on the mains supply/earthing? A nasty floating "earth" voltage?
 
Huevos

Huevos

Satellite Freak
Messages
5,994
My Satellite Setup
57E to 58W, C-band and Ku, DVB-S2, 4:2:2 and blindscan.
My Location
38.5ºN, 0.5ºW
Tivù said:
Something nasty on the mains supply/earthing? A nasty floating "earth" voltage?
I don't think so. I've thought about static and earth voltages, etc, but thought that would cause terminal damage to the box. In this case though it seems to be the front end getting damaged.
 
Lazarus

Lazarus

Tout Rond Bon Oeuf
Staff member
Messages
25,576
My Satellite Setup
80cm Motorised.
Several small Dishes.
Much else.
My Location
North York Moors
Ok.

Well my last stab in the dark is Electromagnetic Pulse type interfenence from eg Airport/Military Radar. But I've never heard of it doing much other than mild and temporary disruption.

Bizarre.

I shall follow the Thread with interest and can only hope you don't sacrifice too many more boxes whilst putting the customer right!
 
C

Crisbe

Regular Member
Messages
88
My Satellite Setup
Currently, Nokia 1800S with satscan, analogue receiver, Nokia 9800S, D box with DVB2000, 90cm solid offset dish, Panasonic tv with inbuilt freesat. Sky + HD (for the wife, mostly!)
My Location
South Coast, Hampshire
Silly question,

Has anyone done any electrical work at the house recently, and maybe run a power cable alongside the feed to the dish, without leaving any seperation between them?

What I am thinking is, if the guy is a DIYer and has maybe done something like put up an outside light with the cable run alongside the dish feed it could be inducing AC voltage in to the cable when powered on, which in turn might be injuring the tuner.

The reason I mention this is because I once had a friend who had problems with his telephone. Every evening, if you phoned him you would hear a loud buzz on the line, daytimes it was fine. He called a telephone engineer out and landed up paying for the call out. It turned out a cable, he had put in, to a light for his driveway, was alongside the phone line as it came down the wall, and just a few feet in parallel was enough to induce several volts of AC on to the line.
 
Huevos

Huevos

Satellite Freak
Messages
5,994
My Satellite Setup
57E to 58W, C-band and Ku, DVB-S2, 4:2:2 and blindscan.
My Location
38.5ºN, 0.5ºW
I changed the LNB too. I don't know if that could have been sending some nasty harmonic into the receiver and doing damage to the front end like that. I've checked high and low bands (both polarisations) with a spectrum and there doesn't appear to be any nasty high power spike, unless it is intermittent. Number 3 box hasn't blown yet; fingers crossed. Any more ideas?
 
woborny

woborny

Specialist Contributor
Messages
1,065
My Satellite Setup
1.8m Dish, most Sky and Freesat receivers, 80cm on Illusion motor and Dreambox DM7025, TDT, TDT HD, Ariva 100e,
My Location
Gandia, 70kms south of Valencia, Spain
or what about the power supply ie the plug and house circuits?
are they using cheap "chineese shop" extention plugs?
what is the voltage in the house - ie the wonderful spanish power supply - i went to somewhone whos voltage was going down to 190v when they used the oven and thats when they started to loose certian programems on their sky box!!
 
Huevos

Huevos

Satellite Freak
Messages
5,994
My Satellite Setup
57E to 58W, C-band and Ku, DVB-S2, 4:2:2 and blindscan.
My Location
38.5ºN, 0.5ºW
woborny said:
or what about the power supply ie the plug and house circuits?
are they using cheap "chineese shop" extention plugs?
what is the voltage in the house - ie the wonderful spanish power supply - i went to somewhone whos voltage was going down to 190v when they used the oven and thats when they started to loose certian programems on their sky box!!
My home voltage is often down there or lower and my box still works fine. I'm not saying you're wrong though; I could never hold an ADSL connection for more than 10 minutes and it would drop when the aircon started, or anything else for that matter. Now I'm using a 12V, 30 amp Diamond Antenna power supply for nearly everything in the office. Voltage level is 100% stable whatever the mains is doing.

I haven't checked for over-voltage but the power supply should take care of that, and even if it didn't and the internal voltage rose to a dangerous level why would it just desensitize the tuner?
 
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