LG Plasma turning itself off and then on again

Jez

Jez

Jez

Caporegime
Joined
18 Oct 2002
Posts
33,073
Hi,

Long shot but perhaps someone here has experienced this or may have an idea as to what may be wrong;

I have a 2 year old 50" LG Plasma screen, recently it has taken upon itself to randomly switch to standby when in use after a period of time. It will then sit with its red LED lit as if it is in standby, but in a completely unresponsive state whatsoever (no buttons do anything), and then after around 2-5 minutes will randomly turn itself back on and resume what it was doing. Pulling the power while it is unresponsive results in a relay click, and a power down, but plugging it back in while still in this weird unresponsive period simply results in it sitting unresponsive for the same period until it wakes up again.

Obviously this is very annoying and unworkable, but i am loathed to bin a sub 2 year old thin bezel modern plasma panel :(

Any ideas as to what may be wrong anyone?
 
Oh...i didnt consider that..i doubt it? Its well over 12 months old...

I didnt even consider a warranty...usually my stuff is all far too old :p I was thinking more along the lines of replacing its PSU or various logic boards
 
Checked LG warranty, it was 12 months long as i thought. So definitely no warranty.

Before i open it up i suppose i should at least pursue LG/Amazon (amazon purchase) for goodwill? Is that worth doing?
 
Its not under warranty, i checked the LG site and it is indeed 12 months only.

I think i will have paid via Amex Platinum, i wonder if they are worth a call. I'll try Amazon too
 
Amazon just politely told me that due to it being 25 months old (older than i thought) that they cannot do anything and have sent me LG's details.

I will try LG for goodwill, others are suggesting that i pressure amazon via SOGA.

Not sure this is worth the argument though, the parts for this TV are so cheap that it might be worth swallowing this as bad luck and fixing it myself which would see resolution within a few days.
 
Yep, i will call LG and try them. Although it is not worth me paying anything much even if they will subsidise an engineer visit due to the below. I will then pressure Amazon via SOGA.

If all else fails i just priced up replacing literally every board in the entire TV at around £60 :p Parts for the TV seem very readily available on eBay, i guess as its still a fairly recent model. A PSU board is around £15 for example.
 
Oh really, weird....but that has to be worth a go.....

Did yours do this after a good while into your ownership?

I wonder if the firmware you flashed has different tolerances built in or something which prevented the shut downs? Did you require anything special to update the firmware? I do not recall seeing a firmware update option within its user menus. I am aware that there are hidden engineering menus but my understanding is that to access these you require an engineering remote?
 
Just downloaded a firmware service manual...there is a newer firmware release since the date i bought the TV.

Looks like a faff with USB sticks etc but has to be worth a go...:)
 
Nice, i'll give this a try when i get in later :) It says to just bung the firmware file into a LG_DTV directory on the root of a USB stick and plug it in, i assume the tv auto detects the file and comes up with an upgrade message?
 
Yep i will be trying it out as soon as i get in, i wont hold my breath as it sort of looks like a hardware fault to me, but mad_allans story certainly makes it worth trying.
 
Thanks, i will keep at them next week when i get a quiet moment at the office :)

I opened the TV up today to take a look, unfortunately i cannot diagnose the issue, everything looks spot on (no blown/bulging caps etc) :(
 
If all else fails the PSU will be my first port of call then :)

Annoyingly i cant see anything wrong with it, i almost wish it had obviously blown caps to at least confirm where the fault lies.
 
Ok, so the TV doesnt seem to have any fault if ran with the case back left off. This would have to indicate overheating and a safety threshold which is cause a power down rest period...would everyone agree?

The power supply is the only item within the TV which seems to get very warm other than the screen itself.
 
Ive still not done anything about this as it is working flawlessly with the case back off :p

I will have to order a PSU i think, its not worth getting engineers involved and trying to build a case for a complaint - a PSU is £15 on ebay :p
 
Just finally got around to fixing this properly the other week, so thought it would mention it in case anyone googles this issue like i was.

I bought a PSU, swapped it, no difference - kept turning off and on when it got warm. Luckily the PSU was only about £10 from eBay so a cheap fail there.

I then obviously started looking at the other boards and noticed that the heatsink on the processing unit of the main board (AV board) was quite loose, and cold to the touch. Seemed odd that there would be a heatsink on a cold chip. Upon closer inspection the processor was burning hot underneath this, with a visible air gap and no thermal paste between the two. This tiny heatsink was only held on by some old rubbery glue stuff, which had gone brittle and i guess had given way over time.

Long and short, i ripped off the tiny heatsink on the processor, and hot glued a much larger heatsink onto it, which i pulled from an old ATI radeon graphics card. I made sure to use a nice amount of thermal paste from a PC CPU.

Perfect ever since, the new heatsink gets luke warm at most :)
 
You must log in or register to reply here.
Back
Top Bottom