# Strange set-top box channel changing



## Nikki (Jun 9, 2002)

My TiVo and Freeview set-top box are in a cabinet with opaque doors and infrared repeater. They were put in the cabinet recently. This arrangement is creating a strange phenomenon when channel changes are made to the set-top box. TiVo is taking several minutes to send the infrared command from the infrared cable. Any further channel changes made are simply buffered by TiVo and are sent at delayed intervals of again several minutes. The problem is cured by leaving the cabinet door fully open. Commands are then sent immediately and any buffered IR commands are sent in quick succession.

What exactly is creating this situation? How does TiVo know the cabinet door is open or closed? I can only imagine that TiVo is sending a test IR command from its front panel and this is being reflected back from the cabinet door at full intensity because of the proximity and TiVo is then deciding to hold off from sending any further commands until the reflected signal's intensity is lowered, by means of opening the cabinet door etc. Why it's doing this is another question. The cabinet door is white. I think I'll try placing a piece of black paper between the door and TiVo.

Nikki


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## Cainam (May 25, 2004)

Are you sure you don't have the IR blaster turned to on in the Set-Top box control menu? It does not need to be if you are using the cables.


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## Nikki (Jun 9, 2002)

It's off. But I'll think I'll attempt to analyse if there's anything coming from the front panel, anyway.

Nikki


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## ...coolstream (Dec 10, 2005)

How exactly do you switch it off?

I did a quick check of the options in the list, and the nearest I could see was the 'none of the above' option.


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## BrianHughes (Jan 21, 2001)

Tivo will hold off sending any Ir if it detects other Ir giving the delayed symptoms you see. Check for stray Ir, perhaps the repeater is picking up interference and sending that out as Ir. Or perhaps your cabinet is so warm that the door itself is glowing in Ir


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## Pete77 (Aug 1, 2006)

As Brian indicates having another IR signal sending at the time Tivo wants to send causes Tivo to try again a few minutes later. So you need to find out what clashing IR source you have.


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## AMc (Mar 22, 2002)

It's almost certainly IR reflecting around inside the cabinet with the doors open it's not a problem but shut they provide enough reflectivity to cause the behaviour.

I would imagine your IR repeater is leaking IR all the time and Tivo is seeing that and holding off. People with Video Senders (same tech) have reported the same problem with low level interference. Most AV electronics are only 'listening' for their codes so ignore the background noise, but as Tivo is waiting for a pause to send it gets upset.

You may need to reposition the IR emitter of the repeater or add a ferrite core around the repeater's DC power supply cable (ask in Maplin). You could also attach some black cloth to the inside of the doors to reduce their reflectivity.

You can see IR signals if you use the viewfinder of a camcorder, digital camera or camera phone which can be extremely useful!


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## Pete77 (Aug 1, 2006)

I have my Tivo in a Philips tv cabinet with smoked glass doors at the front and don't seem to get this problem with it sending out its signal via the IR wands to the Panasonic Sky box. But then the cabinet is open to the outside world at the back and there is also a shelf between the Sky Panasonic box that the Tivo IR wands control and the Tivo itself.

I did sometimes used to experience these channel change delays when attempting to control my Tivo using a video sender attached to my kitchen television.


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## Nikki (Jun 9, 2002)

Sticking some shiny black paper from some advertising to the back of the white cabinet door appears to have removed the delay. It's very tight inside the cabinet. The door is no more than 1cm from TiVo's front panel. What posters are suggesting seems consistent with the delay behaviour. Forgot to also mention the RF pyramid repeater. There's a lot of IR sources inside there. So spurious IR is probably being reflected back by the cabinet door without much loss in intensity causing TiVo to wait for a break. Sounds logical.

Nikki


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## AMc (Mar 22, 2002)

Glad the simplest thing worked 

Watch out for heat build up in the cabinet when the heating is on or in summer.
I had to remove the back of my cabinet and replace it with a metal brace to keep everything within a sensible temperature.

Tivo reports its internal temp on one of the menu pages - I'd be worried if it got above 42/43C.


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## Pete77 (Aug 1, 2006)

AMc said:


> and replace it with a metal brace to keep everything within a sensible temperature.


Philips made their late 90s wooden sided glass fronted tv cabinets with an open back and I doubt this was done to save money but for good practical reasons. Many people use cabinets to house AV equipment that are actually normal items of household furniture with only a small hole cut in them for the cables whereas they should be cutting out the back too.



> Tivo reports its internal temp on one of the menu pages - I'd be worried if it got above 42/43C.


I live in the countryside and not the town but on the hottest 30C+ days in the summer at the hottest time of day my Tivo was hitting a maximum of 44C (plenty of days) up to 46C (the hottest day of the year). It generally runs at 37C in a 21C living room temp and will run as cool as 32C if I go away and set the heating down to a background 15C minimum in the winter. It used to run at lower temperatures with the original Quantum 30Gb and 15Gb drives.

Most hard drives are rated to run ok up to 60C so I doubt the odd very hot day in the summer under 50C internal temeprature does any serious harm. Running temperatures of my HP notebook before I bought a cooling base for it (when the original motherboard burned out after a year of 7 day a week running) were unacceptably high.


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## Nikki (Jun 9, 2002)

I've got TiVoWeb, so monitoring the temperature is just a couple of mouse clicks away. The cabinet is a fitted cabinet that I designed for an alcove. The back panel is against the wall with a clearance of 1-2cm. I could perforate the back panel which would allow more fresh air to enter or vent above the bookcase which sits on the cabinet. Currently, I have two holes at either end of the cabinet with a 90mm PC fan attached to each. The temperature of TiVo runs between 37-41C depending on the speed of the fans. This probably won't be good enough for summer, so I may have to drill further vent holes and add some active PC fan controllers.

Nikki


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## Pete77 (Aug 1, 2006)

Nikki said:


> The temperature of TiVo runs between 37-41C depending on the speed of the fans. This probably won't be good enough for summer, so I may have to drill further vent holes and add some active PC fan controllers.


In winter with my living room here not exceeding 21C and going as low as 15C (if away) and with 2 x 250Gb Samsung hard drives and Cachecard with 512MB of RAM installed my Tivo System Information temps vary between 32C and 37C so your 37C to 41C at this time of year is probably a little hot. Also don't forget the actual hard drives can run hotter than this and that the A drive runs hotter than the B drive (if fitted). My A drive is currently at 38C but my B drive is at 31C. This is because the A drive is nearer to the power supply.

If you have smartctl on your Tivo you can check on the individual drive temperatures with the command "smartctl -a /dev/hda" and "smartctl -a /dev/hdb" (for the A and B drives respectively) at the telnet prompt. Unsurprisingly its the item entitled Temperature Celsius on the resulting output".


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## Nikki (Jun 9, 2002)

Pete77 said:


> If you have smartctl on your Tivo you can check on the individual drive temperatures with the command "smartctl -a /dev/hda" and "smartctl -a /dev/hdb" (for the A and B drives respectively) at the telnet prompt. Unsurprisingly its the item entitled Temperature Celsius on the resulting output".


This command doesn't shed too much information. Any ideas?

bash-2.02# smartctl -a /dev/hda
Device: Maxtor 6L300R0 Supports ATA Version 7
Drive supports S.M.A.R.T. and is enabled
Check S.M.A.R.T. Passed

General Smart Values:
Off-line data collection status: (0x00) Offline data collection activity was
never started

Total time to complete off-line
data collection: ( 0) Seconds

Offline data collection
Capabilities: (0x00) Off-line data collection not supported

Smart Capablilities: (0x0000) automatic saving of SMART data
is not implemented

Error logging capability: (0x00) Error logging NOT supported

Vendor Specific SMART Attributes with Thresholds:
Revision Number: 4096
Attribute Flag Value Worst Threshold Raw Value
( 3)Spin Up Time 0x27c3 080 000 063 00ef22906600
Device does not support Error Logging
Device does not support Self Test Logging


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## Pete77 (Aug 1, 2006)

Nikki said:


> General Smart Values:
> Off-line data collection status: (0x00) Offline data collection activity was
> never started
> 
> ...


Smart reporting for drives has to be enabled when they are out of the Tivo and in a PC (unless it has been set on by the manufacturer by default). This is generally done with the Hitachi FeatureSet tool which works on all brands of 3.5" drives or the manufacturer may have provided their own tool to do this. So probably Smart reporting has not been enabled.

Also updating to the latest version of smartctl may remedy the problem. This can be done by ftp'ng it to the Tivo. Hopefully the one on the Planetbuilders site is up to date:-

See www.planetbuilders.org/tivo/tivo_upgrade_diary.html



> - Grabbed smartctl.gz from http://www.erik.rainey.name/tivo/ or http://www.************.com/forum/showthread.php?t=31223
> ftp'd smartctl.gz to tivo:/var/hack/bin
> telnet tivo
> 
> ...


Substitute deal data base without the spaces for the above asterisks.

If there is no improvement after updating smartctl then either you need to pull the drive and enable Smart or the drive doesn't support it (unlikely if made in the last 3 or 4 years).


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## AMc (Mar 22, 2002)

Any passive venting you add is likely to counter act the active cooling your fans are doing. As soon as you put more holes in you disrupt the airflow inside.

Ideally you would want to get cool air in at the front of the base of the cabinet and vent warm air out of the back at the top. That way convection will help to draw air through. The bookcase should add a chimney effect to help draw air out.
If you can perforate the front of the base/shelf and relocate the fans to the top back blowing out that should work well.

My winter Tivo temps are oftn higher than summer because the room tends to be heated more by the central heating and the wood burner than by sunshine. Direct sun on your cabinet would obviously be a concern.

I'm not sure how much you need to worry, it depends on how much equipment is in there, how hot it runs and how often it all gets used together. AV equipment likes to be ventilated but it is designed to work at room temperature and the reference for Tivo would be expected to work in places like Florida without air con.

If I were you I would get an electronic indoor/outdoor thermometer and put the outdoor sensor in the cabinet and the indoor unit on top. Keep an eye on it and see how big the difference gets over the course of a few days before you get concerned.

If you do decide to go for more active cooling there are a couple of good threads in the home cinema furniture section over at www.avforums.com. People using external hard drive caddies to hold fan controllers so the fans are only spun up when needed etc.


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