Mechnical Al
New Member
I have a 12 year old Foxsat HDR on a Sky antenna installation which is approx 2 years older, which has worked perfectly, albeit only doing the basics; watching + recording + playing. It lost reception of all channels…. on Christmas day would you believe. An auto and manual retune found nothing, along with our postcode becoming invalid, with the message check antenna connections displayed. I checked at the rear of the HDR and at the wall plate and they seemed secure, but I de-powered and remade them after a wishful spray of Servisol, but the fault persisted. I didn’t get the ladder out to check at the antenna as it’s a long way up at the top of a gable end, but I took a zoomed in picture, for what it’s worth, and saw no obvious disconnections or birdstrike damage etc.
As a best guess attempt at fault diagnosis between a U/S box, or U/S LNB, I checked for the placarded 13/18v dc at the rear connections, but measured only 0.4v on both, ( with the antenna leads disconnected of course). This voltage stayed the same with standard and high power (for long cables) selected in the hidden menu, I did read para 8 of the what every HDR owner should know thread, and this doesn’t clarify the 13/18v, but describes a 5v antenna amplifier supply. I hoped to test for that but the menu options have closed down on me so much, that settings is no longer available.
I’ve inspected the PSU, hoping to find something simple like bulging caps, or a blown fuse, but sadly not, and measured the outputs at 12.4v & 6.04v, and stable when loaded by connection to the main board, when displaying both boot and menu. A little above the stencilled figures, but seems close enough.
There is what looks like a tiny relay on the LNB input section PCB, stencilled ‘KC170’ so I audibly checked it with a bit of plastic tube as a stethoscope, and it does positively click at power up, and power off. But the PCB tracks are way too tiny to go poking around blindly with multimeter probes.
I emailed Humax Tech Support, describing the no signal problem, and specifically asking about the 0-4v, and if & when should the 13/18vdc be present at the back of the HDR. All they told me was they no longer support this model, but said from what I told them, it seems the box is working normally, but to be sure, I should try my box on another antenna, and/or another box on my antenna.
Woah…I only have one of each, but even if I had access to others I’d be cautious about whether a fault on the LNB could damage another receiver, or a fault on my receiver damage a neighbour’s LNB.
So if Humax are implying that 0.4v is normal, I’m wondering if that means it’s somehow ‘in idle’ with no LNB connected, and perhaps it needs to see a load to make it ramp-up to operating voltage. There’s a 750mA limit on the placard so with my basic electrics knowledge, I’d expect that I should be able to connect a 12v 2w car instrument panel bulb, (or 2 in series, just in case there is 18v on there) and at least get light!
That didn’t work. Current flow at 0.4v into a single 286 pea bulb was only 5.3uA, on both connections.
I don’t have a signal strength meter to test the LNB, so to see how they’re powered I looked up circuit diagrams for simple DIY ones. Bah…..It appears they use the receiver as a power source ……so no point me buying or making one!
But I’m also wondering; If the LNB was at fault, it’s at least dual output so is it likely that both outputs would fail simultaneously ?
I hope this isn’t too much info, and I have searched for similar topics, as per forum newbie instructions, but even the closest, (by BJ_Racer Freesat Tune Fails), still has some antenna function, so I haven’t found any useful clues in that thread.
It’s probably unrelated, but this fault occurred along with remote control failure, ( another long story) discovered when I found the empty channel list was mysteriously set to 21 Jan 2021, which I thought was simply because programmes aren’t listed that far in advance. I thought I’d be the hero by simply selecting to current date…..but things went downhill, as detailed above!
Hopefully you folks will have seen this all before and recognise the wailings of a novice, and be kind enough to suggest what I should try next, thanks.
As a best guess attempt at fault diagnosis between a U/S box, or U/S LNB, I checked for the placarded 13/18v dc at the rear connections, but measured only 0.4v on both, ( with the antenna leads disconnected of course). This voltage stayed the same with standard and high power (for long cables) selected in the hidden menu, I did read para 8 of the what every HDR owner should know thread, and this doesn’t clarify the 13/18v, but describes a 5v antenna amplifier supply. I hoped to test for that but the menu options have closed down on me so much, that settings is no longer available.
I’ve inspected the PSU, hoping to find something simple like bulging caps, or a blown fuse, but sadly not, and measured the outputs at 12.4v & 6.04v, and stable when loaded by connection to the main board, when displaying both boot and menu. A little above the stencilled figures, but seems close enough.
There is what looks like a tiny relay on the LNB input section PCB, stencilled ‘KC170’ so I audibly checked it with a bit of plastic tube as a stethoscope, and it does positively click at power up, and power off. But the PCB tracks are way too tiny to go poking around blindly with multimeter probes.
I emailed Humax Tech Support, describing the no signal problem, and specifically asking about the 0-4v, and if & when should the 13/18vdc be present at the back of the HDR. All they told me was they no longer support this model, but said from what I told them, it seems the box is working normally, but to be sure, I should try my box on another antenna, and/or another box on my antenna.
Woah…I only have one of each, but even if I had access to others I’d be cautious about whether a fault on the LNB could damage another receiver, or a fault on my receiver damage a neighbour’s LNB.
So if Humax are implying that 0.4v is normal, I’m wondering if that means it’s somehow ‘in idle’ with no LNB connected, and perhaps it needs to see a load to make it ramp-up to operating voltage. There’s a 750mA limit on the placard so with my basic electrics knowledge, I’d expect that I should be able to connect a 12v 2w car instrument panel bulb, (or 2 in series, just in case there is 18v on there) and at least get light!
That didn’t work. Current flow at 0.4v into a single 286 pea bulb was only 5.3uA, on both connections.
I don’t have a signal strength meter to test the LNB, so to see how they’re powered I looked up circuit diagrams for simple DIY ones. Bah…..It appears they use the receiver as a power source ……so no point me buying or making one!
But I’m also wondering; If the LNB was at fault, it’s at least dual output so is it likely that both outputs would fail simultaneously ?
I hope this isn’t too much info, and I have searched for similar topics, as per forum newbie instructions, but even the closest, (by BJ_Racer Freesat Tune Fails), still has some antenna function, so I haven’t found any useful clues in that thread.
It’s probably unrelated, but this fault occurred along with remote control failure, ( another long story) discovered when I found the empty channel list was mysteriously set to 21 Jan 2021, which I thought was simply because programmes aren’t listed that far in advance. I thought I’d be the hero by simply selecting to current date…..but things went downhill, as detailed above!
Hopefully you folks will have seen this all before and recognise the wailings of a novice, and be kind enough to suggest what I should try next, thanks.
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but as you intimated, a recheck would be confirmatory thing for OP to do. I also suspect there is current limiting citcuitry within the box, that a whisker of outer braid across one of the F sockets would kick into action.