The TV Engineer
Established Member
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- Mar 2, 2006
- Messages
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Hi,
I noticed a few Q's about colour patches, colour bars etc on RPTV sets,
Mainly the 3LCD configuration.. So, After doing a Sony KDFE42A12U at work.. I decided that a description might help some of you understand whats what,
And maybe give you some pointers for a DIY repair.
This is the KDFE42A12U sony, But the KDFE50A12U is the same.
The Optical block is generally very similar for LCD RPTV's
Please Note, Dismantling your TV could cause damage if your not experienced, so if in doubt.. consult a service engineer.
This particular set had service mode accessed by the customer, and he lost the picture completely so be very careful what buttons your pressing if in service menu. Or it could mean a new one of these...
This procedure does not require service menu access, it is purely mechanical.
OK this is the picture with a signal generator outputting a pure white display..
obviously a nasty red band at the bottom, and a blue band at the top..
So, remove the back cover to see this
Unclip the board on the right and carefully unplug the connectors.. you might want to make note of what plug goes where, on the ones that are the same sizes.
This next piece is what keeps the optical block aligned..
It is held by 4 screws, 2 top, 2 bottom. Do not undo the silver screw!! or the smaller one next to it.
Next, undo the 2 screws holding the lamp housing in place
The optical block is held by 2 screws..
And one more holds the lamp housing in place at the far front..
Once this is all free, you can separate the optical block from the lamp housing.. remove the lamp now if you havent already.
the lamps power socket can be removed by 1 silver screw on the base of the optical block.
There is a bunch of cables etc you need to unplug, but you will get the idea..
Eventually you will end up with this unit..
Take out the 4 screws holding the grey cover..
And then 3 of the 4 screws holding this board and metal case in place..
Lift the cable clamps gently, to free the ribbon cables..
Then 3 more screws holding this cover in place..
Once that cover is of you can remove this part from the front..
You will need to examine this for any heat damage, the plastic housing has been known to melt when the cooling vents get blocked, and the glass in front of the lamp can crack.
Ok now you can separate the optic block from the cooling fan unit.. some more silver screws here..
This is what the Fan unit looks like inside, you probably wont need to take this apart, it rarely gets even a speck of dust in there
Ok, now, undo the 4 black screws on the front of the block, now make sure you do NOT undo any of the silver screws that hold the silver plates in position.... These are factory aligned.
Ok, now that lot is apart, you need to clean it.. Use compressed air if you have access to a compressor, or even the Air duster cans you can buy..
Be careful of the fragile ribbon cables though.
And do not undo any of the LCD panels, Colour filters.. as these are also aligned during manufacturing.. and are absolutely critical!!.. Mess with these and you will cause permanent errors, and convergence issues that wont be fixable!
OK, once you are happy, put it all back together in reverse order...
Now, If you have done it right, and take your time because its a lot of effort to get it all apart again! (i spent over a day on this one)
You will end up with a nice clear crisp image..
Our signal generator on white again... as you can see.. no more Colour issues.
Hope this was of help to some of the forum members..
And remember, if you dont want to attempt this.. take it to a qualified repairer.
I noticed a few Q's about colour patches, colour bars etc on RPTV sets,
Mainly the 3LCD configuration.. So, After doing a Sony KDFE42A12U at work.. I decided that a description might help some of you understand whats what,
And maybe give you some pointers for a DIY repair.
This is the KDFE42A12U sony, But the KDFE50A12U is the same.
The Optical block is generally very similar for LCD RPTV's
Please Note, Dismantling your TV could cause damage if your not experienced, so if in doubt.. consult a service engineer.
This particular set had service mode accessed by the customer, and he lost the picture completely so be very careful what buttons your pressing if in service menu. Or it could mean a new one of these...
This procedure does not require service menu access, it is purely mechanical.
OK this is the picture with a signal generator outputting a pure white display..
obviously a nasty red band at the bottom, and a blue band at the top..
So, remove the back cover to see this
Unclip the board on the right and carefully unplug the connectors.. you might want to make note of what plug goes where, on the ones that are the same sizes.
This next piece is what keeps the optical block aligned..
It is held by 4 screws, 2 top, 2 bottom. Do not undo the silver screw!! or the smaller one next to it.
Next, undo the 2 screws holding the lamp housing in place
The optical block is held by 2 screws..
And one more holds the lamp housing in place at the far front..
Once this is all free, you can separate the optical block from the lamp housing.. remove the lamp now if you havent already.
the lamps power socket can be removed by 1 silver screw on the base of the optical block.
There is a bunch of cables etc you need to unplug, but you will get the idea..
Eventually you will end up with this unit..
Take out the 4 screws holding the grey cover..
And then 3 of the 4 screws holding this board and metal case in place..
Lift the cable clamps gently, to free the ribbon cables..
Then 3 more screws holding this cover in place..
Once that cover is of you can remove this part from the front..
You will need to examine this for any heat damage, the plastic housing has been known to melt when the cooling vents get blocked, and the glass in front of the lamp can crack.
Ok now you can separate the optic block from the cooling fan unit.. some more silver screws here..
This is what the Fan unit looks like inside, you probably wont need to take this apart, it rarely gets even a speck of dust in there
Ok, now, undo the 4 black screws on the front of the block, now make sure you do NOT undo any of the silver screws that hold the silver plates in position.... These are factory aligned.
Ok, now that lot is apart, you need to clean it.. Use compressed air if you have access to a compressor, or even the Air duster cans you can buy..
Be careful of the fragile ribbon cables though.
And do not undo any of the LCD panels, Colour filters.. as these are also aligned during manufacturing.. and are absolutely critical!!.. Mess with these and you will cause permanent errors, and convergence issues that wont be fixable!
OK, once you are happy, put it all back together in reverse order...
Now, If you have done it right, and take your time because its a lot of effort to get it all apart again! (i spent over a day on this one)
You will end up with a nice clear crisp image..
Our signal generator on white again... as you can see.. no more Colour issues.
Hope this was of help to some of the forum members..
And remember, if you dont want to attempt this.. take it to a qualified repairer.
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