Lg flatron w2252tq-pf

[s_henya]

Re: Lg flatron w2252tq-pf

hey selldoor,

im not used to checking shorts that way,
usually, im using the diode mode (buzzer),
no shorts were found that way,
voltage checking:

U5:
PIN1: 4.88vdc
PIN2: 3.34vdc
PIN3: 0vdc

how much should the tcon board get anyway? about 5v?

the main tcon fuse F1: got 4.9vdc

[Rtech]

Re: Lg flatron w2252tq-pf

Your readings are fine,and as you have tested both the Logic and Power Supply in another Monitor and they are working as they should,then provided you used the Logic to Screen cable from the faulty Monitor in that test, then as very little information would be available for the T-con Board, a replacement Screen would seem to be the only solution.

[selldoor]

Re: Lg flatron w2252tq-pf

Is this board permanently attached to the panel by the yellowish flat cables?
If so with it all on and connected can you gently press on the tab connectors
and see if it changes the pattern on the screen.
Also there are two components on the right hand side of the board Q1 & Q2 can you read the part numbers. We could do with some panel experts on this
alexanna would know just where to do what tests.

[s_henya]

Re: Lg flatron w2252tq-pf

Sorry selldoor i'm unable to read the writing on Q1 Q2
But i went over all the tcon lvds connector pins, no change,
Its weird, on a cold start i have strips all over,
after a minute or two, the strips dissapear,
And the image is pretty good, but half of the screen has much more light than the other.

Did some more voltage testing on Q1 Q2:

Q1:
PIN1:5.7
PIN2:12.2
PIN3:5.23
Q1:
PIN1:5.7
PIN2:0.05
PIN3:5.23

Any ideas? by the way i have never replaced a smd transistor,
tried once, on a old bad mainboard, transistors came out totally bad!.
maybe to long on the hot air 450 degres ruined them....

[selldoor]

Re: Lg flatron w2252tq-pf

0.05 doesnt look good but I dont really know. We need someone who does to look at it.
Sometimes if you clean with a little isopropyl alcohol on a qtip it brings the writing up- tried a magnifying glass?
U is usually a regulator and Q is usually a transistor but not always - great system!

This one of our members removing a component just needs confidence - Ive not done it.

http://www.youtube.com/watch?v=0TJQ9-fRs0M&feature=plcp

Others recommend cutting the legs then desoldering the tab then removing the leg ends on a 3 leg plus tab type.

I recall working on a 20"LG and whilst it did not have the problems you have
I broke the brown clip that secured the flat cable (I think to the socket on the mainboard) I packed it with a piece of very thin plastic like a food tray.
and I think that fixed it.
There was also an adjustment button called "engine" and I think if you make some adjustments using that it displays a before and after so perhaps that
needs looking at.

[budm]

Re: Lg flatron w2252tq-pf

Do the readings on Q1 and Q2 change when it is cold and after warm up?

[s_henya]

Re: Lg flatron w2252tq-pf

hey budm,

the voltages are pretty constant no matter cold or warm start.

the 0.05 volt is my guess,

i dont really know how tcon board works.

but one transistor is good and one side of the picture is good and the other bad,

if i knew what type of transistor is it i would order one or two and replace,
but i cant read clearly as you can see...

[selldoor]

Re: Lg flatron w2252tq-pf

Hi been trying to track down your ICs but failed - what is the Tcon board number. I dont think you put up a picture yet?
Also my ramblings in post 25 did have a point but I didint make it. I was going to suggest that whilst it was on - half and half you try pressing on the panel cable at the socket. ( Same effect as my packing it)
The next bit about the engine also is based on a fact the engine button has a
shop/ display mode.
Here is the handbook
http://www.manualowl.com/m/LG/W2252TQ-TF/Manual/54624
Its on page 17A

[s_henya]

Re: Lg flatron w2252tq-pf

selldor your guide helped a bit, thank you

the half screen was a function :-)

but there a still some strips on power on and little lines on the screen,

im going to investigate some more tommorow and update as soon as possible

and add some more pictures

[s_henya]

Re: Lg flatron w2252tq-pf

the tcon model: LM220WE1-TLE1
i've added 4 more pics it goes from left to right
where do you want me to press?

[selldoor]

Re: Lg flatron w2252tq-pf

Hi - Good at least thats the half dull sorted. I will continue to try and find what the Qs are
in the meantime I would upgrade the caps on the main board.
The pressing point was an alternative fix for the dull half so i think you can forget that,

[s_henya]

Re: Lg flatron w2252tq-pf

if you mean the logic board already recapped it with fresh caps
no change at all, the psu inverter board is another thing :-)

btw the only info i found about the tcon was this, not very helpful...

[selldoor]

Re: Lg flatron w2252tq-pf

Sorry my error - meant the power supply board - whilst I know you say it works fine in with the 19" screen I just wonder if it need a bit more "umph" to drive the 22"
I Think it is just 5 caps and I see people sell cap kits for that model so it is a sign that
the caps need replacing often else they wouldnt sell the kits. I am going out now so
will look at your attachment later.

[selldoor]

Re: Lg flatron w2252tq-pf

Read the pdf - none the wiser.
Still failing to find Q1 and Q2. How difficult would it be to measure that 0.05 pin as it was going through its stripey startup? Also can you measure the 5v test point near U5 as its going through startup to see if it fluctuates.

[s_henya]

Re: Lg flatron w2252tq-pf

got a 20.5 samsung with a little crack,

plugged the cracked screen to the power supply and logic board of the lg

and the picture is perfect,

plugged the samsung power supply and logic board and the image is even more

scrambeled,

so the tcon board a bad for sure,

i need some instructions for fixing it if even possible,

could be a bad ic or lvds connector?

the tcon is attached with ribbon cables to the screen and i dont think it could be replaced.

[selldoor]

Re: Lg flatron w2252tq-pf

Well that quite bad news. Can you try the known to be good lvds cable on the LG panel or is it different.

"the tcon is attached with ribbon cables to the screen and i dont think it could be replaced."

Unfortunately Correct.

Were you able to do the Q1 and Q2 test when cold and when warm as Budm suggested.

[s_henya]

Re: Lg flatron w2252tq-pf

sorry for not updating on voltage testing,
the voltages are pretty constant,

i tried the power supply and power board with the samsung lvds cable
on the lg screen and the picture was bad,
tried all the lg parts on the samsung screen and the picture was perfect so the problem is either the lvds connector on the tcon board or some other ic chip. the Q is very likely, i dont know a good substitute.

[selldoor]

Re: Lg flatron w2252tq-pf

Really need help from members who understand Tcons. In the meantime try and and do as many measurments as possible - there are lots of test points like VCC+5V, VDD, VGL, VGH, SDRAM_VDD, VLS, 3V, SSC_VDD, D-VDD, and S_VDD(?) and a cluster on the right hand side of the board near the Q1 & Q2 Vcomp VSTR GRES DISC GVDD-E GVDD-O and so on. The results may mean something to somebody.
Could also try warming the tcon with a hairdryer and see if it sorts itself out quicker, then try and pin it down to a part of the board by just heating sections. Sadly may turn out to be a fault within the panel

[s_henya]

Re: Lg flatron w2252tq-pf

good idea, should i use hot air from the rework station, or hairdryer?

which temp should i pick?

i will do some voltage testing on the lvds connector, maybe the connector itself is defective

i will update tonight or tommorow.

thanks again selldoor, i feel i already learned a lot more out of this monitor repair.

[selldoor]

Re: Lg flatron w2252tq-pf

Doesnt matter what you use- not too hot though and not near the bonded cables at the top in case the bonding melts and makes it even worse.