T4 keeps freezing, recording 0MB files

[mallycat]

In the last few months I have had an issue where my T4 freezes

• In the morning, I can see a screen from the night before (eg Media list) but the device is non-responsive
  There are recordings in the list, but they are phantom recordings - duration 0:00, size = 0MB

I updated the firmware to the latest available, but that didn't fix the problem - no change in behaviour.

The device is about 2.5 years old.

I read on some other threads about issues with tuner cards - I don't know if that is a likely culprit or not.

Can anyone help and suggest possible causes and remedies?

Matt

[Grumpy_Geoff]

Were those "phantom recordings" from scheduled timers?
Is the hard drive okay? Do a file system check (Menu>>Storage).
What firmware version did you update to, as "latest available" says nothing really? The latest release is 20191106 (https://beyonwiz.com.au/downloads/).
Do you get live TV from all four tuners? Try each tuner in turn, setting it as the preferred tuner (MENU>>Setup>>Tuner>>Tuner allocation). Change to a different broadcaster (e.g. SBS to ABC) to force retuning and use of that tuner.
The tuners are paired A/B and C/D, so if you get live TV issues try connecting the aerial lead to each tuner in turn to locate the problem.

[prl]

While the issues about the tuner voltage regulators on the T4 (not the "tuner cards") often results in a pair of tuners dropping out, it doesn't necessarily cause that problem. Our T4 went directly from working perfectly to not being bootable because of corrosion due to breakdown products of the thermal cement on the tuner regulators.

As peteru recently said in another topic about what looked like the same issue, any T4 that has survived to date without having the tuner regulator problem dealt with should probably have the tuner regulator problem addressed, because it will almost certainly start causing problems at some time.

It's worth doing even if the immediate problem isn't caused by the tuner regulators.

[Grumpy_Geoff]

As peteru recently said in another topic about what looked like the same issue, any T4 that has survived to date without having the tuner regulator problem dealt with should probably have the tuner regulator problem addressed, because it will almost certainly start causing problems at some time.

Whilst I can't possibly know the mainboard revision, I'm initially going with it being a Rev1.2 board as the T4 is 2.5 years old and thus I'm guessing not likely using the inferior Chinese thermal paste.
If I'm correctly remembering what Warkus told me, not all batches of the T4 have the issue.
Of course, I could be wrong.

[prl]

This is the post from peteru that I was referring to.

I don't have a T4 with a rev2 board, just one already-repaired rev1 board, and a pre-release.

Part of the problem (at least with the rev 1 board) is that the pair of regulators for each tuner have different heights. That means that the heat sink that straddles the pair doesn't make optimal contact with the tops of the regulators, and so the average thickness of the thermal paste is greater under the heat sinks. That means less efficient cooling of the regulators, as well the problem with the thermal breakdown of the paste.

I don't know whether the rev2 boards have the paired regulators in packages that are the same height.

[Grumpy_Geoff]

I don't know whether the rev2 boards have the paired regulators in packages that are the same height.

Apparently they're the same size. In this post warkus states -
"In the second or newer batch of T4 units, they changed the 3.3v regulators to a TO-252 design also (slightly larger than the SOT-223) and thus the 2 regulators under each heatsink are the same size. It hasn't stopped the problem though, ive done 3.3v regulators from both batches of units newer and older."

So if I understand this issue correctly -

• Some Rev1.1 boards will have the thermal paste breakdown issue
• Rev1.1 boards will have the power regulator thermal cooling issue
• Rev1.2 boards may have power regulator failures

[mallycat]

Thanks for the suggestions. It seems like it is an issue with tuner A. I never noticed the tuner names in the channel banner at the bottom of he screen when changing channels before now. The A tuner has no signal. I worked out how to disable that tuner and rebooted. I will wait and see what happens. I have checked the antenna cables and all are ok. So what is the next step? Is this something I can investigate myself by removing the cover, or should I take it to a tech?

[Paul_oz53]

I recommend you send it to warkus (aka Mark Vasile) at Decisive Computer Solutions. He is expert at fixing wizzes and very affordable. He uses Sendle as a courier but AusPost is an option.

Give him a call.

[mallycat]

Thanks all. I think I will run it as a T3 for a few weeks before deciding next steps.

[MrQuade]

Thanks all. I think I will run it as a T3 for a few weeks before deciding next steps.

If it is the regulator problem, and you lost tuner A, you will find that tuner B is also dead. You should check that.

Also, if it is the regulator problem, you'll risking further damage of you keep running the T4.

I would advise not waiting weeks to decide on a course of action.

[mallycat]

Thanks MrQuade. I can confirm that tuner B works.

[prl]

Thanks all. I think I will run it as a T3 for a few weeks before deciding next steps.

If it is the regulator problem, and you lost tuner A, you will find that tuner B is also dead. You should check that.

Although it's common for the regulator problem to show as a tuner pair disappearing (either A+B or C+D), that's only one of many issues that the regulator & thermal cement issue can cause.

Also, if it is the regulator problem, you'll risking further damage of you keep running the T4.

I would advise not waiting weeks to decide on a course of action.

+many

Mallycat, do you feel confident about opening the T4's case and checking for evidence of browning on the cement holding the heatsinks to the tuner regulators?

[mallycat]

Yes, I'm OK about opening it. I put the HDD in when I first purchased it, so it should be fine. Thanks for the advice

[Grumpy_Geoff]

Yes, I'm OK about opening it. I put the HDD in when I first purchased it, so it should be fine. Thanks for the advice

Have a look at the photos in these links then - viewtopic.php?f=45&t=13889#p184413

[mallycat]

ohhhh, nice. Thanks

[prl]

In both my and Geoff's cases, the thermal cement had turned the colour of high percentage dark chocolate, though I think I recall people having problems with it when the visible bits were more biscuit-coloured.

The cement starts its life being white.

The regulators are under a pair of U-shaped black heatsinks near the tuners, just a bit to the front of the front-panel end of the tuners.

[prl]

The regulators with their heat sinks are circled in green. Rev 1.1 board, pre-release T4. The pre-release appears to have the heat sinks attached with epoxy.

The front panel is at the bottom of the image.

[mallycat]

My board looks like it is in good shape, actually

https://share.icloud.com/photos/0lNfAO8 ... Om2smLn87A

[prl]

Yes, there doesn't seem to me any discolouration of the thermal cement.

[stevebow]

When I originally removed the regulator heatsinks back in Oct. 2018 (the T4 (Rev. 1.1 PCB) was around 2 yrs old at that stage), the thermal adhesive was still white and I found no PCB damage due to the adhesive. I wonder if the factory changed adhesives at some point?

Worthy of noting that I do fully shut down the T4 when not in use; perhaps this issue affects mainly those who leave their T4s in Standby mode only?

The daily thermal cycling though has likely contributed to the cracked solder joint that led to my particular problem - either way, you just can't win.