Question Sony 46W5500 overheating / electrical flash & shut down

[LargeStyle]

Hi all, I made a thread on another forum but have had no replies and I'm really stuck and would seriously appreciate some feedback please, so I'll re-post my issue here too.

The TLDR version is my TV presents a spark at the back after several hours use and shuts down and shows 8 flashes of the power LED. I guess the power supply is prime suspect of being faulty, but I really don't know about these things. The full version is as follows...

My 10 year old Sony 46W5500 has as of last week started shutting down after approximately 4 to 6 hours use. I've not timed it specifically, but it's somewhere around that time. I'm suspecting it to be either heat related and / or degraded component(s) but that's just a guess. I have parts available on eBay but I don't know about TV repair at all, so would really appreciate any advice please! I know diagnosing like this is far from ideal, but it's my only option and I'll detail everything I know for diagnosing benefit...

- TV starts and works 100% fine then after this time I hear a significant pop and it completely shuts down and the power LED flashes 8 times. I haven't been able to accurately determine if the pop originates internally or is a power spike going through audio to my stereo (and I never use the internal speakers) - but I'd say it's likely internal. No visual indicators (like a flash) when it pops (*update: I've seen it flash now on popping). TV can be successfully restarted immediately, but I never leave it restarted in fear of causing more damage. I can leave the TV off for about an hour after that, and then it'll work fine again for just a few more hours before shutting down again.

- I ran the TV the other day with the screen turned off (using the TVs power saving option) while just sending audio out to a stereo, and it still shut itself down after the usual period of time.

- I've taken the back cover off just to have a look and clean it, but nothing obvious to an inexperienced eye stood out, in it was already clean in there. Vents aren't blocked either.

- I've done the recommended complete powering down (unplugging from the wall) then doing a complete factory reset on startup. Problem remained so re-updated the firmware to latest official one from Sony, again not fixing issue.

- All 4 HDMI inputs have been tested and work seemingly without fault.

- Connectivity-wise, I have Google Chromecast on HDMI 1 & USB port for power, PS4 on HDMI 2 (from a passive HDMI switch), headphone out (sending audio to an old stereo), and standard UK arial. Nothing has changed with connectivity before and after the power issue.


Despite me not being informed in these matters, as mentioned earlier I can only guess it's having an error because something is getting too hot and / or physically can't tolerate operating for extended periods due to old-age and failing part(s). I'm also guessing that it's not a lose connection as the problem has a consistent pattern(?) As the TV functions perfectly otherwise, and although it's obviously getting / is old now, I'd still like to repair it if possible!


FWIW, here are all the available spare parts I've found currently on eBay that I have available if needs be ... (not that I know what most of these things are)!

Power Supply Board
Main Board
Logic Board
IR Receiver Board
AC Socket
Inverter
Inverter to power supply lead
LVDS Lead
Button Unit
Power Cable
Speakers

Also FWIW: I have the exact same TV but in 52" form in the living room, so I kinda / may have spares for testing purposes, but obviously don't want to pull that apart if I don't have to!

Many many thanks in advance for any input!

Chris.

 

[LargeStyle]

(This second post was from a small few days later than the above)...

So yesterday I ran the TV with the backlight setting on minimum and it operated fine all day long (I had my Chromecast playing in idle mode). After a full daytime of this I then upped the backlight to half for a couple more hours and no fault. I then upped to full backlight and the tv literally sparked out after about half an hour (saw a bright flash over the wall behind, along with the "usual" pop).

Today I've been running the TV without the back panel and had my phone recording video of it so I can see where the flash originates. Yes I know this is far from ideal, but it's simply my only way of diagnosing the / an area of fault. I literally warmed the TV up with a few hours of minimal then half backlight as before, then ramped it to full and it lasted 2.5 hours which didn't produce the fault, and I had to stop due to low phone battery. The TV's was damn toasty to the touch though and probably wasn't far from putting on another light show.

So I'm now even more confused - on one occasion the TV failed after a few hours with the screen having been disabled, while on another occasion the tv lasted all day but only on a low backlight setting. Ultimately, so far those two occasions along with today's backless experiment result in 2 of 3 tests showing a seemingly direct thermal correlation which is why temperature remains my most probable cause of the fault. I've started to suspect faults to be with either the power supply board, the backlight inverter board, or even the lead between the both, but at this point I'm still guessing away!

 

[hang-the-9]

Power board, if that does not work system board is next, but a 10 yr old 46", I would just replace it with a used working set, will cost the same as the parts, and the parts may not fix the issue.

 

[LargeStyle]

Thank you hang-the-9 very much for your reply! Very kind for a moderator to answer my first forum post!

Yeah, I've bought a used power board from eBay for just £9 delivered a short while ago. If that doesn't fix it then the system board is £40, so as you rightly pointed out I'll have to weigh this up as the set was only £90 anyway.

Will update when have more results. Thanks again!

 

[LargeStyle]

So the replacement power board didn't fix the issue. Was strange as it initially passed a longer than usually survivable stress test (8 hours) on the first day of installing the replacement board, but on the second night it turned itself off after about half that time. Still weighing up the option to persist with more parts, but haven't made my mind up yet. Will update this thread if I have anything further to add.

 

[hang-the-9]

So the replacement power board didn't fix the issue. Was strange as it initially passed a longer than usually survivable stress test (8 hours) on the first day of installing the replacement board, but on the second night it turned itself off after about half that time. Still weighing up the option to persist with more parts, but haven't made my mind up yet. Will update this thread if I have anything further to add.

That's the gamble you take with repairing (or at least trying to ) comparing to just replacing with new or used, is buying 80 worth of parts that have a 60% chance of fixing it better than just spending 120 to replace it? Maybe not, since if they don't fix it and you want to replace it, you now spent 200 on a 120 item. Now if you had a $600 new TV and were going to spend 60 to try to fix it, sure worth it all day long to attempt to save 500.