Stuck at START SYSTEM even with no hard disc

[Owen Smith]

My newest and least used HDR Fox T2 now gets stuck at START SYSTEM on the display. I have disconnected the hard disc data and power cables but the problem remains so it isn't the capacitor like I thought. Is there anything I can check or is it just a case of getting my spare out of the loft and hoping it works?

 

[Owen Smith]

I've checked the power supply outputs with a multimeter and they all measure as expected based on what is printed on the power supply PCB next to the connector. 5.8V measures as about 6.4V and 12V measures about 12.3V. Feels like a main board issue, is there anything I can check there?

 

[Owen Smith]

Recordings on the hard disc aren't a concern by the way. I have them all auto decrypting so they should be usable with another main board, and if not it's only telly and I have an Apple TV 4K for catchup. I prefer to use the HDR Fox T2 because I get 5.1 sound on some BBC and C4 programmes whereas their catchup services are only stereo, and I can skip adverts on commercial services.

 

[Owen Smith]

The large 16V capacitor closest to the 4R7 inductor in the photo below only has 0.89V across it, that feels unlikely for a 16V part. The cpu heatsink gets hot so the cpu is powered.

 

[Black Hole]

is it just a case of getting my spare out of the loft and hoping it works?

Yes, at least in the short to medium term. Attempts to resurrect the failed unit will be a long and detailed process of "knife-and-forking"*, unless by some miracle a firmware reload or system flush restores it, but I see you've started. Best of luck, results will be useful.

Consider that E²PROM (or whatever the particular firmware storage technology might be called) typically only has a data retention time specification of 10 years. The clock might get reset every time we update the firmware, but I doubt that includes the boot loader, and probably not the firmware updater either.

The large 16V capacitor closest to the 4R7 inductor in the photo below only has 0.89V across it, that feels unlikely for a 16V part.

We know that some sections only get powered up under firmware control. This might be one of them. You'll need to trace the circuit in that area and figure out what it's actually supposed to do, and whether the inputs to that section are operating correctly. Alternatively measure the ESR and leakage of that capacitor, or just replace all electrolytics in hope.

I don't want to discourage you, we will all benefit from any information you manage to uncover, but as you've got a spare one...

* That was the colloquial term we used in my era, at my place of work, for debugging on the test bench.

 

[Owen Smith]

Yes, at least in the short to medium term. Attempts to resurrect the failed unit will be a long and detailed process of "knife-and-forking"*, unless by some miracle a firmware reload or system flush restores it, but I see you've started. Best of luck, results will be useful.

It doesn't boot sufficiently to either flush or reload firmware. Or at least I assume it doesn't since it is on "START SYSTEM".

Consider that E²PROM (or whatever the particular firmware storage technology might be called) typically only has a data retention time specification of 10 years. The clock might get reset every time we update the firmware, but I doubt that includes the boot loader, and probably not the firmware updater either.

The firmware is stored in Flash on the HDR Fox T2, as it is in almost everything these days. E2PROM is largely obsolete and generally is used for saving settings on the rare device that still has it.

We know that some sections only get powered up under firmware control. This might be one of them. You'll need to trace the circuit in that area and figure out what it's actually supposed to do, and whether the inputs to that section are operating correctly. Alternatively measure the ESR and leakage of that capacitor, or just replace all electrolytics in hope.

That's beyond my knowledge of electronics I'm afraid. I'm capable of following instructions to repair known faults and I was hoping this might already be known, like the hard disc startup capacitor.

I don't want to discourage you, we will all benefit from any information you manage to uncover, but as you've got a spare one...

I have a second spare at my parents that has already had its hard disc pinched to replace my parents. Their hard disc was arguably faulty from new, it was always trouble and as soon as I installed custom firmware I found it had dozens of bad sectors at only a couple of years old. It was a constant effort every 6 months or so to clean that disc. Finally it locked up on my parents and while I was able to run disc fix on it I didn't want it locking up on them again and I swapped the disc.

 

[Black Hole]

It doesn't boot sufficiently to either flush or reload firmware. Or at least I assume it doesn't

Assume? I did say "by some miracle", but until you conduct the experiment you don't know for sure.

I was hoping this might already be known, like the hard disc startup capacitor.

Nope.

The firmware is stored in Flash on the HDR Fox T2, as it is in almost everything these days. E2PROM is largely obsolete and generally is used for saving settings on the rare device that still has it.

Would that be NOR or NAND Flash? A trivial point. But I thought you said...

That's beyond my knowledge of electronics I'm afraid.

 

[Owen Smith]

Would that be NOR or NAND Flash? A trivial point. But I thought you said...

Not sure. I'd expect NAND since it's running embedded Linux, but it's not certain. I'd have to lookup the chips online.