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Tuner Saga

BMAX

BMAX

Active Member
Some of the regulars may remember a thread from eighteen months ago where I was investigating tuner difficulties following damage caused by a falling picture frame...
Dead HDR-FOXT2? | hummy.tv

...and a follow up six months ago.
HDR Fox T2 loses all signals after a day or 2 unused | hummy.tv

A few weeks ago, prior to a visit to the recycling center, I decided to have a last look at the box.

Hair dryer heat treatment had previously caused a temporary fix. Several forum members have advocated a more radical heat treatment for various other problems, so I decided to attack the pcb with a 2kW heat gun, more in hope than anticipation.

I badly under estimated the power of the gun, and the temperature of all the components in the target area rapidly became much hotter than I intended, but I don’t think it was hot enough to melt the solder. Everything suddenly went blank (no signal, etc).

Fearing that I had overdone the process and wrecked the board, I switched off, then re-powered after everything had cooled down. Surprisingly, the box seemed to work OK.

That was three weeks ago and the box has been in daily use since, with frequent test cycling of the various features as well as normal service use. There has been no recurrence of any problems.

Conclusions:

I still have no idea what the problem was, except that it was not the tuners themselves, but further upstream in the processing chain.

I have little idea of the temperature that the components got up to with the heat gun, A spot check with an IR thermometer indicated that it was probably above 120 degrees Centigrade.

I have no idea how long the board will continue to work, but I will report back any change.

Make of this what you will!

Thanks to those that showed interest, especially BH who kindly donated a spare pcb complete with a pair of good tuners.
 
I've been doing similar the past few months, last time I heated it the whole board it ran for 3 months in standby and turned on daily before failing again.

My last effort a few days ago was to use a 60 watt light bulb to heat the area of the capacitor near the internal usb connector, I've no idea what that controls, but the board came to life after about 2 minutes and has worked for the past 4 days.

I'm not sure, but it also seemed to work intermittently when I was pressing against components in that area. Need to wait until it fails again to try testing more.

Possibly relevant, I've noticed that the SD channels work first and it takes much longer for the HD channels to work, SD & HD are though on different frequencies.
 
BMAX said:
I have little idea of the temperature that the components got up to with the heat gun, A spot check with an IR thermometer indicated that it was probably above 120 degrees Centigrade.
Click to expand...
High temperatures accelerate ageing in ICs rather than kill them outright, and soldering temperature is something like 230ºC (the maximum temperature specs are about the manufacturer providing a guarantee of the environment in which the chip will operate according to specification, and are not absolute limits).

If you don't think you've reached reflow temperature, all I can think of is that you've encouraged a capacitor to work.
 
Been a bit since I posted here last, but I've been getting the same problem with my ageing but immaculate-looking (inside & out) FOXT2, it doesn't get much use which might be why.
Strong signal received from cold start, but no signal processing/picture/sound at all until everything starts to warm up.

I tried the hairdryer trick around the internal USB connector and that cap, and the SD processing came back after about 6mins from cold, stopped the hairdryer and waited for HD which took several hours with a slowly improving picture & sound breakup rate which had difficulty holding.

I then tried heating the area with the blowtorch of a small pen-sized gas-iron (on a low setting), heating that cap and the components between it and the HDD cage, being careful not to overdo it or singe anything.

The result is not ideal, but it seems to be better and holding - from cold, SD kicks in (after an initial 10 second problem-free burst!?) after about 20mins without extra heating instead of around an hour, but HD still takes a good 3-4 hours but then remains stable. Noticed that HD also has that initial 10 second burst on cold start before that cuts out completely for the next few hours, some kind of buffering failing?

An electronics friend says this reaction to heat is classic dry joint syndrome, so I'm wondering whats going on underneath the motherboard?
 
Philbert said:
I tried the hairdryer trick around the internal USB connector and that cap, and the SD processing came back after about 6mins from cold, stopped the hairdryer and waited for HD which took several hours with a slowly improving picture & sound breakup rate which had difficulty holding.
Click to expand...

I replaced the CAP next to the USB on mine, but it made no difference, still the same behaviour ... given up on it for now
 
Philbert said:
I then tried heating the area with the blowtorch of a small pen-sized gas-iron (on a low setting), heating that cap and the components between it and the HDD cage, being careful not to overdo it or singe anything.
Click to expand...
I had the feeling that heat around the heat sink had more effect. Perhaps you could try the blow torch there before you give up..

hjug said:
Possibly relevant, I've noticed that the SD channels work first and it takes much longer for the HD channels to work, SD & HD are though on different frequencies.
Click to expand...
I also found that HD channels were affected before SD

Mine is still working OK after 8 nonths.
 
I think I'll count my blessings with this until a more definite solution turns up.

Both SD and HD long recordings are perfectly ok so long as the FOXT2 is allowed to warm up enough first, about 15-30mins for SD and 2-3 hours for HD, these times should improve as the weather gets warmer.

Timer recordings are awkward as I have to remember to turn it on in good time and then wait for the program guide to appear to set the recording timer, but its workable for just the occasional recording.
Don't know about timer recordings if I'm away for a few days yet though, I'll probably have to leave it on 24/7 for those...
 
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