troubleshooting a tv power supply

R!f@@

Joined Apr 2, 2009
10,004
Ahh!! See that's where u are wrong.
See the other end of the cable, this is where the loose lies from what I have seen.

You did not comment on the heat produced by the sink.
 

Thread Starter

johndoe45

Joined Jan 30, 2010
364
oh. so how would i fix the loose on that side?

and the heat. i left it on for a little and took fan off (don't remember how long it was left on. i will let you know exactly tomorrow when i try to fix loose on other end). just taped. and sink wasn't that hot. barely warm if even warm.
 

R!f@@

Joined Apr 2, 2009
10,004
That' good...warm to the touch is much better
Still no picture...
It's time to take some LVDS measurements.
I'm quite bzy these days as you might know, But I'll whip up something for you soon.
keep checking for late edit to this post.
 

R!f@@

Joined Apr 2, 2009
10,004
See the pic.

It seems u are bending this connector.
But I like you to check the other end which has the LCD panel drivers.
See if that end is OK.

I need to see some voltages. Put back the TV as it was, see that the fan is held in place. See the connector shown in the pic, I want you to measure the DC voltage at these pins. To measure you might have to turn the board the other way, or do what ever you can to measure the voltages.
Meter ground should be the metal shield, this shield is connected to negative or ground.
Simply turn on the TV and just measure the DC voltage at each pin of that connector and note them down in a way we both can understand, I will leave the numbering method to you.

The LVDS cable will have low voltage signals.
It's a differential data bus, so there will be grounds in between wires and data lines. The data voltage will be typically around 1V. it's possible to get 0.8V or 1.2V...
There will be a Vcc line too. It will be either 3.3V or 5V.

Actually this measurement should be taken at the panel termination but since you are not familiar with it I am asking you to first check at the board termination.
So after seeing the voltages I can suggest anything else.

Be careful not to bridge any pin with the probe. I donno what will happen if you did. Specially the Vcc.
So carefully measure a pin at a time and note 'em down.
 

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loosewire

Joined Apr 25, 2008
1,686
Draw a sketch out line with voltages and pin numbers so we can follow what you are doing.We need more Information to follow your progress.You have gone this far go all the way with more Information on both sides. Name the curcuits as you go.Let us know If any test equipment Is now being used. Go guys
 

R!f@@

Joined Apr 2, 2009
10,004
I build the only reputable repair shop in Male' from ground zero.
and to this day they are making a lot on that name that I worked to give them.
And they stabbed me in the back.
I am done doing things for worthless Maldivians.
I rather help and do it for free for those who appreciate my work.
 

Thread Starter

johndoe45

Joined Jan 30, 2010
364
here it is :D

tv was left plugged in quite awhile while taking measurements. shield didn't get hot

pretty sure there are no errors. but if something looks wrong. i will double check
 

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R!f@@

Joined Apr 2, 2009
10,004
measurements show LVDS signal being produced.
From here u will need a hot gun.
Problem I think lies in the DC to DC converter at driver circuitry

Next is to take the shield cover at the panel top back. Don't do any think yet
I'll show u tonight
 

R!f@@

Joined Apr 2, 2009
10,004
Take a look at the pic.
There are tiny screws holding the shield, you can carefully remove it,
just be gentle, look around the corners for interlocks.

The connector area, and it's surroundings are the area I like to see. Get a good closeup
 

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loosewire

Joined Apr 25, 2008
1,686
Very good continue to use red lines to show voltage and part numbers.
So members can follow by pin numbers and fault areas. This project get better
all the time,don't forget to start laptop thread with red lines. You have the largest
classroom In the world,you deserve the Maldives GOLD METAL or an apple,you
may have to have Retched explain that one.
 

retched

Joined Dec 5, 2009
5,207
...Kids give an apple (the fruit) to their teachers.. sometime because they are in love, and sometimes because they didn't study for a test ;)

But, now-a-days, Im sure a teacher would be more likely to pass you if you gave them a MAC :D
 

Thread Starter

johndoe45

Joined Jan 30, 2010
364
here are the pictures. better lighting to see tracks or is this good?

here is order of pics from left to right

1 2 3 5 4. i uploaded the last two in wrong order

couldn't get screws out so had to use flat head that was barely too big and angled it. so one screw is parlty deformed or whatever you call it for not using the right screwdriver. they were all extremely tight so made it worse.
 

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