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Possible dead tuner? Can i replace?

martypants16

martypants16

Member
Hi All,
As the thread suggests i think a tuner is dead. First of all is there any way to check this? I am running the custom firmware.
The problem seems to be that when the box is running live TV then i get pretty much zero signal most of the time , as if you would if the aerial was disconnected.
It does seem that it records ok though which seems a little odd.
If this is a dead tuner is it easy to replace by a layman?
I have replaced the hard drive several times but have no idea if its possible to replace a tuner...
And if so where can i buy..........?
Thank you.
 
Thank you, i'll take a look. Did some research in the meantime trawling past threads, might be easier just to use the TV tuner for live TV and record onto the Humax for catchup......
 
If one of the tuners is not working, you could also prove it by trying to record two programs (on different Muxs*), at the same time.

* e.g. BBC (PSB1) and ITV1 (PSB2)
 
Re the original hardware release, a unit with a dead motherboard could be a donor for a tuner module, or even one with one dead and one working tuner module... but I'm not sure the modules are identical as one does "in" and the other does "out".

For the revised hardware release, there is only one tuner module but the comment about a donor still applies (which would also have to be the revised hardware).

Hence my constant appeals for people not to chuck out broken units - as a last resort, if you must get rid, send them to me!
 
Hello everyone.

The tuner appears to have died in one of my units (no signal received, no passthrough, etc), so I'm looking at repairing (as there doesn't seem to be an equivalent device around now?).

Black Hole, do you have any applicable spares at present? Or can anyone point me toward the kind of module I'd need to purchase? Original horizontal alignment.

And/or any other advice...?
 
Aaron-B said:
Black Hole, do you have any applicable spares at present?
Click to expand...
Possibly, yes, but you don't know which can it is (as in "tin can") and there is risk (good chance it's the first of course). Frankly I would recommend sourcing another and only looking to repair if all else fails, because of the faff and the potential to fail in repairing.
 
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Black Hole said:
Possibly, yes, but you don't know which can it is (as in "tin can")
Click to expand...
You mean which of the two tuners? I'm getting absolutely no signal detected at all, so I'm assuming it's the first if not both.

But, yeah, I think I'm leaning towards a replacement from eBay. Quite a number from good sellers at good prices. Certainly a lot less hassle!
 
You can check the tuners individually in the hidden diagnostics menu.
Have you had water down the cable or some other physical damage?
 
Absolutely no damage, no.

But - strike all the above! - I've just plugged it in again after about 40 hours with no aerial connected, and 20 hours in standby (not powered off), and it's suddenly working. Both tuners are reporting 100% quality signal with 55-60% strength (normal for where I am located), and it's passing through too.

I'll not count my chickens and assume it's magically fine again, but at least I don't have to act quite so immediately.
 
If of interest to anyone, the latest in the saga is that it's been fine since my previous post, then I saw it die at 6pm last night as I turned the TV on to watch the news. I had a split-second flash of telly before it all went black with no signal.

Checked and un- and re-plugged the aerial again, nothing. Plugged the aerial directly into my second box and all fine from there.

Diagnostics Signal Test is registering 0% strength and quality on both tuners, FWIW.

Back to eBay for another box I suppose!

(Original cabling was aerial > HDR Fox T2 #1 > HDR Fox T2 #2 > TV.)
 
I'm willing to let you have a pair of tuner cans if you want to try a swap out, in the interest of science, but I recommend a replacement box and then fiddle off-line. Note there are other chips involved on the board, but I figure they are decoders rather than anything to do with the RF signal. If one of the data path channels went down, it shouldn't (I believe) stop the other channel continuing to receive. It seems likely that the first tuner is at fault and failing to pass a signal to the second tuner... so if we are to postulate a single point of failure, it would have to be in the input buffer.
 
With the horizontal layout IIRC there are two separate RF tuners and two DVB demodulators. If both tuners aren't working, isn't it also possible that the problem is with the tuner power supply, perhaps as here?
Black Hole said:
... there's 40V (or ±20V) generated for some reason. ...
everthewatcher said:
In olden days a 40V supply would be for a varicap diode tuner. No idea what they're using these days.
...
Click to expand...
Click to expand...
I believe such things are still used in both discrete and integrated RF tuner designs.

The step-up regulator ICs that would generate 40V or +/-20V seem generally to have 10-pin packages: in the HD-Fox T2 IC inventory, U152 is a candidate but there's only one. There appear to be two regulator ICs in the HDR-Fox T2 with similar support component layouts aligned in front of the tuners and DVB demodulators but I can't see the labels in online images.
 
Black Hole said:
I'm willing to let you have a pair of tuner cans if you want to try a swap out, in the interest of science, but I recommend a replacement box and then fiddle off-line. Note there are other chips involved on the board, but I figure they are decoders rather than anything to do with the RF signal. If one of the data path channels went down, it shouldn't (I believe) stop the other channel continuing to receive. It seems likely that the first tuner is at fault and failing to pass a signal to the second tuner... so if we are to postulate a single point of failure, it would have to be in the input buffer.
Click to expand...
Sorry for slow reply, I've not had time to do anything further as yet!

Yes - that sounds a way to go. It'd be good to get those spares and see if it can indeed be done. I'll be in touch when I've got a spare moment to think and plan it out! Thanks. :)
 
Do we know for certain that each metal can contains a tuner? One can is connected to the RF input and the other the RF output.

Where is pass through amplifier situated? Perhaps one can contains both tuners and the other the pass through amplifier. Alternatively they may be identical but with links to configure as RF input or output.
 
xyz321 said:
Do we know for certain that each metal can contains a tuner?
Click to expand...
Not that I know of, it has been a presumption (two tuners, two cans, therefore...). However, they are the same size etc, and it does look (on the PCB) as if there is a similar array of components associated with each can (decoder chips, capacitors).
 
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