T4 HDMI Failing

[MrQuade]

I had an incident when I tried to fire up my T4 this morning to run the latest beta online update.

My T4 has been largely left in Deep Standby for more than a year now since it went for a regulator repair. (My U4 took over as the prime PVR).
I usually only wake it up to update and test things, or it may start up if I get a power failure, though I normally notice that and shut it down shortly after.

I have noticed that it will often refuse to wake in response to a front panel button press or a remote command, though I never bothered to chase that one down.

This morning, cycled power to start it up, but was left with a "Booting" message on the front panel. Cycled power again, same result.
I figured, rather than try to diagnose at this point, I would just reflash.

Reflash seemed to take, but when I was running through the Wizard I noticed quite a lot of discolored shimmering in the background image.
I just chalked that up to a slightly janky HDMI cable that I was using.

However, after rebooting, the shimmering was getting quite severe, and the picture and sound was dropping out for several seconds at a time with only about 5-10 seconds of image in between.

I am thinking that the poor girl is almost kaput. Those regulators might have done a number on more than just the tuners way back when.

I will see if I can do a little bit more testing when I have more time, but leaving it off in the meantime.

Anyone seen similar symptoms with older T4s? I noticed stevebow was reporting similarish sounding symptoms in addition to flash corruption.

[peteru]

Typical symptoms of memory related failures. It could be any number of things.

First place to look would be the quality of the power being delivered to the CPU, RAM and flash.

The next suspects would be damage to motherboard - traces and solder joints.

Next, failing memory or the CPU.

In terms of being able to diagnose the problem, you may be able to identify out of spec voltages with a multimeter and perhaps inspect the motherboard with a magnifying glass. Anything past that level will require a DSO and preferably access to schematics and data sheets for relevant components.

[peteru]

I had a V2 die in a very similar way. Random crashes or lockups, then random screen corruptions, eventually failure to complete the entire boot sequence (first rarely then frequently) and at the end it would lock up very early in the bootloader, even before the flash was checked for availability of firmware. The onset of these symptoms was fairly gradual, but then the deterioration picked up pace. It was almost as if the mean time between failures has halved each time.

It happens. Hardware fails. If you are lucky it goes from working to not working straight away. If you are unlucky you live with a flaky system for a long time before it finally becomes clear what the problem is.

[stevebow]

I noticed quite a lot of discolored shimmering in the background image.

[...]

However, after rebooting, the shimmering was getting quite severe, and the picture and sound was dropping out for several seconds at a time with only about 5-10 seconds of image in between.

[...]

I noticed stevebow was reporting similarish sounding symptoms in addition to flash corruption.

I did?

[MrQuade]

I did?

In variou reports about your tuners failing, you had pinned some problems on bitflips causing failures to progress past booting, and a reflash temporarily solving the issue.

I am guessing your T4 is suffering from the same gradual decline that mine is and bits and pieces are falling apart due to out of spec components/voltages throughout.

[stevebow]

Sorry, I thought you were referring to video issues "in addition to flash corruption", which I don't recall ever having. Just the flashmem bitflipping. I did report elsewhere that I scoped the supply voltage of the NAND flashmem for voltage level and noise, and noted nothing of concern.