loss of RF input

[MikeSh]

what's that orange stuff on the main board, around the RF IN daughter-board?

As BH says - looks like rusty water pooling.
Your hand picture just confirms it.

 

[prpr]

no sign of water damage on the outside, i.e. the RF connectors, but…

Really? I can see significant signs of corrosion looking at them.

what's that orange stuff on the main board, around the RF IN daughter-board? And doesn't that daughter-board look like it's full of this orange stuff.

Rust?

Definitely. There's dust, rust and general filth all over the board. This has been getting wet for quite a long time I would say. I'm surprised it's stayed working this long.
Time to replace that co-ax and make sure it's water-tight at the top before you kill anything else.

 

[cdmackay]

Yup

I will keep the Humax, for playback, and for spares (other than RF input), as I think I have another somewhere. But I need to get the aerial cable sorted first.

I'll go with an aerial socket plate on the wall, too, which will protect against this sort of nonsense in the future; well, so would a simple extension adaptor. The slight irritation of loss of signal, reflections etc, with an adaptor/plate is perhaps minimal compared with the damage from water leaking down the cable, even if that's unlikely with new cable.

thanks again, all, for the help.

 

[cdmackay]

Really? I can see significant signs of corrosion looking at them.

Definitely. There's dust, rust and general filth all over the board. This has been getting wet for quite a long time I would say. I'm surprised it's stayed working this long.
Time to replace that co-ax and make sure it's water-tight at the top before you kill anything else.

The connectors on the outside may have some air corrosion, very slight; with the eye, as opposed to a close-up pic, they look fine. The output connector looks the same, and it's never had a wet (or dry) cable connected to it.

Yes, I'm amazed it was working fine a few days ago, with all that rust!

 

[prpr]

The slight irritation of loss of signal, reflections etc, with an adaptor/plate

If you're that close to the signal threshold that it makes a significant difference, then you need an amplifier at the top end in the first place.

 

[cdmackay]

If you're that close to the signal threshold that it makes a significant difference, then you need an amplifier at the top end in the first place.

Yes, good point, thanks. And I'm not.

Which reminds me to put coupler-connectors on the 4 cables from the LNB on our dish, to protect the two FoxSat Humaxen from the same fate, if their cables ever spring a leak, too.

thanks again!

 

[/df]

The main damage appears to have come from damp running along the core through what must be a tubular socket running inside the module. But when the box is running, isn't it warm enough to create humidity and spread damp around? Or is the damage done when the box is idle for extended periods?

I don't suppose a few minutes of a hair drier on a low setting (with its slotted nozzle if available) would do any harm to a visibly damp aerial socket/tuner module. But the pix show a tuner module just waiting to be unsoldered and cleaned up (the main PCB too).

The 2 Sony LSIs just in front are the demodulators. Also visible in one view are a pair of TO220-5 packages further back, most likely voltage regulators such as the LT1580 specified in the BCM7405 application circuit.

If cleaning fails, it should be possible to swap the damaged module. I assume that even if available a replacement module from Humax would be more expensive then a second-hand partially or even fully working HDR-Fox T2; I wonder if a broken eBay HD-Fox T2 would be a source of the same tuner module? Through the top vents I estimate the HD module to be about 4x2x0.75 (cm, lxhxw).

Not entirely off-topic, no. 1001 in a series: Why software is a more congenial profession than [electrician|TV aerial installer|plumber|tree surgeon|...].

I had to replace a 12' length of aerial cable that had completely failed without the outer insulation appearing to be affected, the last piece, maybe 20%, of a run from a loft distribution amp to the furthest end of the house. I couldn't see evidence of recent water ingress but it was way mucky at the bottom end. The remaining old, possibly decades, segment, it ran down a wall behind ivy and through to the aerial socket. The symptom was that there was a better signal using me as an aerial than by plugging into the socket. Confirmation of the diagnosis was bypassing the segment through a roof window. Although the guilty cable is long gone, I recollect it having the tubular dielectric.

 

[everthewatcher]

Coming in late on this, this is why you don't used semi-airspaced coax - the stuff with the mini pipes in the inner insulation - for aerial downleads. Use the foam-insulated stuff instead.

Even then water can wick down the braid. Assuming a Yagi, make sure the cap can't come off the aerial's terminal box by putting a some self-amalgamating tape around it and drill a 3-4mm drain hole at the lowest point. I also give everything a coating of the original Waxolyl that I still have here from the '70s.

 

[Trev]

I suppose it can wick down the braid, but it won't just run down the air spacing like a damn water pipe will it. I have not heard of a water problem with foam insulation, only the air spaced stuff.

 

[Black Hole]

I wonder if a broken eBay HD-Fox T2 would be a source of the same tuner module?

There's an issue with that: HD-FOX can only receive one mux at a time, and still has to pass through the signal, so it can't be exactly the same module as either of the two modules in the HDR-FOX (unless they have over-engineered it, but that would impact the bill of materials and therefore the bottom line). In the HDR-FOX, one module has to be configured to receive and daisy-chain, and the other has to be configured to daisy-chain and output.

 

[cdmackay]

thanks again, all. I wondered about replacing the module(s), but obviously if I have to buy a T2 to get them, I might as well just replace the T2 entirely, especially now we can replace its encryption key via the CF, so my not-decrypted recordings may still be viewed on it. I think I have a spare T2 somewhere…

I'll certainly ask my aerial chap about the type of cable (foam); I don't fancy mucking about on our moss-covered roof without a proper roof ladder (or even with one).

 

[MikeSh]

I'll certainly ask my aerial chap about the type of cable (foam); I don't fancy mucking about on our moss-covered roof without a proper roof ladder (or even with one).

If the aerial is as old as the cable I'd consider getting him to replace that, and maybe the mast & brackets too while he's at it. (It's quite possible he may find the aerial is in too poor condition to rewire anyway.)
They don't last forever and it might save another visit in a few years time.

 

[Black Hole]

My recollection of VHF/UHF co-ax from the 1970s is it was all "cellular". The spacer couldn't be solid because it would make the cable too stiff, and maybe nobody had thought of it or there wasn't the ability to manufacture foam spacer cheaply enough.

I have little doubt all the cable in my house is cellular, but I have connectors where the drop from the aerials come in under the eaves and the connections to the aerials start going up before they loop downwards (or at least they did before I had an installer fit new aerials for the 700MHz clearance - I must check).

 

[/df]

There's an issue with that: HD-FOX can only receive one mux at a time, and still has to pass through the signal, so it can't be exactly the same module as either of the two modules in the HDR-FOX (unless they have over-engineered it, but that would impact the bill of materials and therefore the bottom line). In the HDR-FOX, one module has to be configured to receive and daisy-chain, and the other has to be configured to daisy-chain and output.

Bang on. Looking more closely (but without actually opening it up), it seems that the tuner module in the HD has both antenna connectors. I haven't seen the revised HDR with similar vertically aligned connectors; perhaps it has a dualled version of the HD module that can tune two channels at once. Obviously the 2 demodulators give the ability to pull programmes from 2 muxes at once.

 

[cdmackay]

If the aerial is as old as the cable I'd consider getting him to replace that, and maybe the mast & brackets too while he's at it. (It's quite possible he may find the aerial is in too poor condition to rewire anyway.)
They don't last forever and it might save another visit in a few years time.

Good point but no, the aerial is much newer; I had a wide(r)-band aerial fitted when our previous aerial stopped working as Sandy Heath changed UHF channels. I don't recall the cable being changed at the same time (sadly). The aerial is probably 10–15 years old, the cable could be 40, or more.

 

[Black Hole]

I would still be inclined to renew the aerial, as the man-up-a-ladder is already paid for.

 

[everthewatcher]

I would still be inclined to renew the aerial, as the man-up-a-ladder is already paid for.

And go for a log periodic, not some chap cheap 'contract' Yagi.

 

[Black Hole]

Agreed. For 'contract' read 'cheapest available (and made like it)'.