TV Signal disappears but only while recording

I don't know what a Mux or LCN is
Glossary (click)

WebIF >> Diagnostics >> Mux Info will tell you what your tuning is, and which services are on what mux. This is basic stuff.

LCN
Logical Channel Number - These are the "channel numbers" that you find allocated to the services on your digital TV / set-top box (including the Humax) - for example: "1" gets you BBC1, "9" is BBC FOUR, "12" is Dave and so on.​
In the days of UHF analogue TV, UK TV transmission frequencies were given channel numbers from 21 to 69 (each 8MHz apart starting from channel 21 = 471.25MHz), and the broadcast stations (from any one transmitter) had a whole channel each. To get universal coverage across the UK requires lots of transmitters, and because neighbouring transmitters would interfere with each other if they were on the same frequency (even if transmitting the same station on that frequency) different channels have to be allocated to the same station from different transmitters, so ultimately five TV stations were the most that could be fitted into the UK coverage (BBC1, BBC2, ITV, Channel 4, Five).​
DVB (Digital Video Broadcasting) replaces the analogue one-station-per-broadcast-channel with a digital data stream on each broadcast channel, and similar conditions apply to interference from adjacent transmitters but now there are up to six "multiplexes" from each transmitter, broadcast on similar channel number allocations as before. However, inside each multiplex (or "mux") the data stream has sufficient capacity for about 10 StDef TV stations (more if they time-share) plus many audio-only and text services, or 4 HiDef TV stations.​
This is where the LCN come in. Each service across all the multiplexes is allocated a unique LCN, and this is the position on the digital TV's "tuning dial" where the service will be found - regardless of what region you are in. The LCN information is embedded in the data stream, so when the TV or set-top box tunes itself in BBC1 is always on 1, Dave on 12, and so on.​
Disambiguation: To avoid confusion, I recommend the following usages: 'Channel' should refer to the frequency used for the transmission; 'Station' or 'Service' should refer to an individual TV, radio, or text feed within the digital multiplex ('service' is the industry standard); and 'LCN' is the number you have to dial in to the TV/STB to receive a particular service.​

Multiplex, Mux

The point about digital transmission, be it terrestrial or satellite, is that a number of services can be transmitted on one frequency (instead of the old days of analogue, when only one service occupied the whole of the frequency). The process of sharing multiple data streams over one transmission channel is called "multiplexing", and a transmission channel carrying multiple services is called a "multiplex" (abbreviated to "mux"). See also LCN.​
 
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I have just pressed record on BBC1 HD and found that I can view any other HD channel fine through the Humax but I can not view any SD channels while recording BBC1HD.
What about the other way round? Record BBC One (LCN 1, DVB-T mux.) and view BBC One HD (LCN 101, DVB-T2 mux.).

I think you have a tuner fault as well, although it doesn't test as faulty. Unfortunately you cannot run the test on Tuner 2 while Tuner 1 is providing recording data so it is impossible to prove. And even if you could, what can you do about it? Not a lot is the answer. /df may be right with post #11.
 
What about the other way round? Record BBC One (LCN 1, DVB-T mux.) and view BBC One HD (LCN 101, DVB-T2 mux.). That works fine but I think it must be a hardware fault so I am going to get my hands on another hdr-fox t2 and try to put my existing hard drive into it to save my recordings or I might copy them off via USB first perhaps.

Either way thank you all for your help
 
If you temporarily swap Humaxes between rooms and check whether the problems move with the box would eliminate any questions about whether the problems was due to the aerial connection.
Similarly if you swapped disks between humaxes it would eliminate the disk as cause of the problems

AFAIK noone has yet attempted any repairs to fix tuner problems but replacing capacitors has been quite successful for resolving problems with disk startup issues - there may be a repair possible but beyond my electronics knowledge.
 
That is a good idea. I am away this weekend but will try both of those when I am back :thumbsup:

Although I have repaired boards to component level 30 years ago I was rubbish at doing that so if it proves to be a component I will swap out the humax
 
That works fine but I think it must be a hardware fault
Looks like failure of the DVB-T demodulator section of tuner 2 then, the other three sections (both DVB-T2s and tuner 1's DVB-T) being OK.
try to put my existing hard drive into it to save my recordings
You need to decrypt them first if doing that.
or I might copy them off via USB first perhaps.
That will decrypt SD during the copy process. To decrypt HD you need to have unprotected them first.
If you temporarily swap Humaxes between rooms and check whether the problems move with the box would eliminate any questions about whether the problems was due to the aerial connection.
Similarly if you swapped disks between humaxes it would eliminate the disk as cause of the problems
It won't be any of that. I think it's already proved beyond reasonable/realistic doubt.
I will swap out the humax
Sounds like the only sensible option to me.
 
The picture shows the two tuner paths with the associated demodulators and regulators. If the problem isn't just muck shorting something, decent photos, one from above and one from a shallow angle in the direction "regulators"-->"tuners", might show an obviously failed component.
 

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I did some work last year with help from BH but due to failing eyesight I could not reliably identify the relevant components. If anyone has photos similat to the one posted by /df above, It would considerably help me.
 
I cropped that from the pinned Disassembly thread, but the posted original is not very high resolution. The pictures here are better.
 
Thanks. That is the actual board supplied by BH from which I salvaged the tuners. I was more interested in the component functional descriptions eg "tuners", "modulators" "regulators" etc
 
I don't have an open HDR but see here for some HD component breakdown, and the entire thread for more background.

Although I confidently wrote "regulators" over the two 5-pin TO-style ICs, they're bigger than all the ones seen in that thread and the designation isn't readable in any of the pics. By comparison with the HD breakdown, they're the same RichTek RT9183H Ultra Low Dropout 1.5A Linear Regulator in a TO-263-5 package (adjustable voltage, 2.2W: 5 active pins, all the same length) that is lined up with the demodulator on the HD board.

Neither I nor G recall anyone having ever unsoldered the RF can around the tuner module to see what's inside.
 
I stopped using humax went for zgemma twin h9 brilliant far better than humax. You won't regret it. Zgemma can recording two channels while watching third channels plus can playback streaming via tablet. The ssd can be slot in the back of the zgemma box. I been using it for nearly over the year now with no issues. Can recording all HD channels and copy to PC computer via filezilla. I never buy humax ever again
 
That twin DVB-S receiver wouldn't replace OP's HDR-Fox T2 though this version does have a single DVB-T tuner. This H7C model has two DVB-T tuners and you can mount a 2.5" drive inside. But good luck getting a Freeview EPG on any of them.
 
Mine isn't freeview as mine is freesat Zgemma H9 Twin with two satellite cable feeds in the back of the box with 2.5'' ssd slot in. I brought it from world of satellite year ago. Full Epg guide was great with mini TV mode with open vix v6.2
 
Mine isn't freeview as mine is freesat Zgemma H9 Twin with two satellite cable feeds in the back of the box with 2.5'' ssd slot in. I brought it from world of satellite year ago. Full Epg guide was great with mini TV mode with open vix v6.2
I think it is confusing for you to post about a satellite box in a terrestrial section of the forum. It would be helpful if you posted about your experiences in the Freesat section of this forum as there are quite a lot of people looking for suggestions for a replacement satellite box as Humax don't have any offerings and the Arris box isn't held in high regard.
 
Thanks all. It was a hardware problem. I have swapped the HDD to another and all is fixed now
 
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