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Freeview Box Remote...

PostPosted: Wed Sep 16, 2015 9:19 pm
by jskinner97
Hi All, I "found" a Bush DFTA16 freeview box literally in a field soaking wet. Me being me I bought it home, dried it off and low and behold it worked. It has channel up and down buttons on the front, but because it was obviously last re-tuned a long time ago I need to re tune it.

I bought a genuine replacement remote on eBay for a few quid and confirmed it was working with the old digital camera trick, but it doesn't work on the freeview box? I have inspected the area around the IR Receiver and all seems fine, I also went over the solder with no avail...

Any ideas? I have no clue how IR receivers and remotes work by the way :ccb

Re: Freeview Box Remote...

PostPosted: Wed Sep 16, 2015 10:41 pm
by Herald1360
The digicam trick doesn't guarantee working, only that something is driving the IR LED.

Having said that, though, you may well have just found why the thing was ditched in the first place.

Re: Freeview Box Remote...

PostPosted: Wed Sep 16, 2015 11:14 pm
by mark pirate
Or it is not the right remote for the box....

Re: Freeview Box Remote...

PostPosted: Thu Sep 17, 2015 7:38 am
by Wolfie
With a Crystal earpiece you could monitor the IR data coming out of the IR Receiver.. doesn't tell you if it's correct, just if it's there. (same goes for video on other stuff)..
Or.. you could get/borrow one of those programmable IR Controls, they usually have a 'step through the codes' option until something happens.

I love crystal earpieces for fault finding.. erm... low voltage of course although they will withstand more voltage than your ear.

Re: Freeview Box Remote...

PostPosted: Thu Sep 17, 2015 3:00 pm
by mark pirate
Another trick is to use a radio on MW, tune to a quiet spot and operate the remote close to the radio.
You will hear the pulses :qq1

Re: Freeview Box Remote...

PostPosted: Fri Sep 18, 2015 10:04 am
by davegsm82
Hi Jamie,

The best method to test it would be to take a photo diode and reverse bias it with a resistor to a 9v supply our so. Stick a scope on the junction where the diode and resistor meet and look at the resulting waveform when you point the remote at the PD.

You should see pulses somewhere in the region of 5-20ms (typical), if you expand the trace in one of the pulses you should be able to see the carrier frequency of 38 or so khz. If the carrier is missing then the ceramic resonator is knackered, if nothing at all then the IR emitter is faulty.

If all looks well then put the scope on the output of the IR receiver in the set top box, you should see the same data pulses as before but with the carrier frequency removed (just like AM radio really).

IR receivers have been known to fail, ive done a fair amount of work with remote controls and PIC micros, made my own bespoke remote for my amplifier last time.