Sharp LC-60LE650X - Temperature warning

[Logic West]

Hi,

I have a TV with the following symptoms:

When powering on with the remote, it turns on and displays a warning msg in the bottom right corner "Temperature", then immediately goes back off.

It was working fine until it was removed from the wall for painting and the fault started after it was put back up.

I have removed the rear cover and inspected all the boards. The only thing that I could see that looked like a problem was the heatsink on the main board, which I think Sharp refer to as "main unit". It is soldered in place with a very thick thermal pad to transfer the heat. The heatsink was a little crooked and was fairly easy to wobble from side to side.

I desoldered it to take a look at the thermal pad and it is in good condition. After resoldering it, it is very firm and doesn't wobble back and forth at all so I think the TV may have been dropped and damaged those solder joints. The same fault remains though. Could it be that I need to reset the error code or something? Or am I barking up the wrong tree?

I appreciate any advice.

Cheers,

Alex

[chrismurphy]

Re: Sharp LC-60LE650X - Temperature warning

Fan failure

[Logic West]

Re: Sharp LC-60LE650X - Temperature warning

Hi Chris, there is no fan in this model. At least I can't see one. I have a sharp parts guide for it and I can't find a fan listed in there.

[Logic West]

Re: Sharp LC-60LE650X - Temperature warning

Does anyone know if that kind of error message could be from one of the boards other than the main board overheating? I mean, could the power supply board or the t-con board overheating generate that error or would it be something on the main board overheating?

[budm]

Re: Sharp LC-60LE650X - Temperature warning

Can we see the pictures of what we are dealing with?
Show the back side of the TV so we can see all the boards.
Power supply board P/N and good clear straight shot pictures of the whole board?
Main board P/N?

[Logic West]

Re: Sharp LC-60LE650X - Temperature warning

Hi,

I took a pic of the rear but where I have the TV, the lighting is not great for photos so I took each board out and snapped them individually. I'm not sure which number on it is the p/n.

Incidentally, I noticed that there appears to be some liquid running under the large BGA chip on the tcon board. I wonder if that is the source of my problems. That chip has a really thick thermal pad to couple it to the metal chassis of the TV so it must generate some heat.

Thanks for your attention

Alex

[Logic West]

Re: Sharp LC-60LE650X - Temperature warning

I have a proper sweep freq ultrasonic cleaner that I use for macbook logic boards. Can you think of any reason why the tcon board shouldn't be cleaned in the same way? I'll fire up the heater now cos the tank takes a couple of hours to heat up.

[Logic West]

Re: Sharp LC-60LE650X - Temperature warning

Never mind, I couldn't find any sign of liquid on the inside of the rear cover. It looks like the liquid under the BGA ship is just liquid that has leached out of the big thick thermal pad and it has come through the vias and onto the balls. I doubt that liquid is electrically conductive.

[budm]

Re: Sharp LC-60LE650X - Temperature warning

I doubt that will be the problem, the thing is if they have temperature sensor to detect over temperature problem, I cannot see how it will trigger so fast when TV changes state from standby to fully on, I would expect the bad past to slowly heat up but not instant to put TV into shutdown mode. So if you check the temperature on the boards when TV is in standby do feel any parts that gets too hot to touch? It may be that the sensor is faulty.

[Logic West]

Re: Sharp LC-60LE650X - Temperature warning

The fact that the problem started only after the TV had been unmounted and remounted to the wall made me think that something physically must have been damaged or dislodged. I looked over all the boards for anything resembling thermistors or sensors attached to heatsinks but I can't find any. SMT thermistors just look like resistors anyway so not easy to find them without a schematic.

Perhaps the TV flexed and a trace was broken or a SMT chip pad became disconnected. I'll put the boards back in and do as you say, it's a good idea.

[budm]

Re: Sharp LC-60LE650X - Temperature warning

You can try cooling the main board with compress canned air upside down or have the fan blowing on the main board for a while then power up the TV to see if the error will still show up or not right away.
"Perhaps the TV flexed and a trace was broken or a SMT chip pad became disconnected. I'll put the boards back in and do as you say, it's a good idea." you may be correct.
I am still looking through the pictures of the boards.
There is nothing in the user manual either about the Temperature warning message.
BTW: Sharp RUNTKB057WJQZ (DPS-168JP A) Power Supply / LED Board LC-60LE600U
is used in LC-60LE600U so I look at the service manual for the Temperature warning message:
It will show 4-blink code.
'Judged by monitoring temperature with the temperature sensor.
When the panel temperature is 63°C or more, caution is displayed.
If the panel temperature is 65°C or more, error standby is
activated.
[Released]
Reduce the value of TEMP CAUTION (temperature caution
threshold) and TEMP SHUTDOWN (temperature protection
threshold) in the adjustment process mode menu."
The main board of the LC-60LE600U, it has Thermistor TH3301 that feeds the main MCU IC, so you may want to look at your main board for part with TH** designator.

[Logic West]

Re: Sharp LC-60LE650X - Temperature warning

The boards don't get hot in standby. Cooling the mainboard didn't affect the symptom

I guess it must be either a broken connection or a faulty sensor. Do you think there is any chance that it needs to be reset to factory defaults if there is such a thing with TVs?

[budm]

Re: Sharp LC-60LE650X - Temperature warning

I did not find the service manual for your model to see how to do factory reset.

[Logic West]

Re: Sharp LC-60LE650X - Temperature warning

I found the manual for a slightly different model but the procedure requires you to be able to access the menus anyway so I wouldn't be able to perform it.

Thanks a lot for your help anyway

I think this one will be a real rabbit hole.