Mulja tv repair portal
Equipment Repairs => LCD TV forum => Topic started by: vpauliakas on February 17, 2012,16:34:38
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Hi,
:sign0144:
I have a Philips 26pfl5522 and when turning it only displays a blue screen with horizontal lines, sometimes going to a grey screen. After about half an hour it starts to function normally. If turned off and turned back on right away, it keeps on working normally.
Had a look at the capacitors, and none seem to be bloated. Also checked the service menus and no errors are displayed.
Which component could be causing this, the main board, the power board or the screen controller? I have seen a message in a different post which said a similar problem was solved by replacing the capacitors on the power board (here's a link: http://www.tv.quuq.org/forum/index.php?topic=4950.0). Could this be it?
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caps do not always bloat
replace these in psu use good low esr version panasonic fm or sim
2- 680uF 35VW
1- 680uF 25VW
1- 680uF 10VW
4- 680uF 16VW
1 2200uF 10VW
2- 330uF 16VW
1- 330uF 35VW
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caps do not always bloat
replace these in psu use good low esr version panasonic fm or sim
2- 680uF 35VW
1- 680uF 25VW
1- 680uF 10VW
4- 680uF 16VW
1 2200uF 10VW
2- 330uF 16VW
1- 330uF 35VW
Thank you for your help. Are fm and sim capacitor series names or abbreviations of some sort?
On a related note, could someone recommend a good online store to get these, which ships to UK?
Edit: Just inspected the capacitors on the PSU (Model: PLCD190P3) and have found these capacitors:
2x 1000uF 10V
3x 470uF 25V
2x 680uF 35V
1x 100uF 50V
1x 100uF 450V
1x 100uF 25V
2x 22uF 50V
Did I miss any? Seem to be very different from the ones posted above.
Have checked the stores like mouser.com and while they stock the required components, shipping costs to UK seem a bit high. Does anyone know of a good electronics store based in UK, or at least one which would offer reasonable shipping costs?
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Hi there,
Why not Maplin ? - amazed at their stock coverage when no-one makes/mends anything, anymore.
If more serious, try Wiltsgrove - good on price, if not on range - Chris.
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hi
if still same prob screen
dave
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hi
if still same prob screen
dave
What do you mean by screen? The lcd controller board?
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hi
the LCD Display
dave
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hi
the LCD Display
dave
Thank you for your input, although could you please explain this in more detail? The display itself is intact and it displays the image without any problems once it starts working. I was thinking it is a problem with the boards controlling the panel or the power supplied to them, and I expect to be proven wrong. I came here to search for all possible causes and solutions and I am interested to hear more.
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hi
try and post pic of the fault
dave
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Here is a link to the album showing the progress of the TV turning on.
http://imgur.com/a/dYrXJ
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hi
another way is connect tv to another tv thro scart to scart
if no fault on other tv rules out psu and mainboard think
tcon is built in to screen
dave
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I have tried scart to scart as suggested by Dave. I didn't have an aerial plugged in, but the graphical menus showed up without any problems on the other tv. I was hopping for a psu fault as that is the easiest fix, could still be at fault? If not, what repairs am I looking at? Tcon (timing control board?) was mentioned, can that be replaced without replacing the screen by some means? Is that the little the little circuit board above the main board, under a foil cover and connected by LVDS?
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hi
post pic of inside tv
dave
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Here is a picture of the inside:
http://i.imgur.com/GD6A9.jpg
Another observation - this fault seems to be heat related. If I use a hair dryer to warm the inside of the tv when turning it on, it only takes 3-5 minutes for the video to appear, instead of the usual 20-30 minutes. Could it be a loose connection on the lcd controller board which closes when the metal casing extracts when warming up? Or is it some electrical component changing its characteristics when warmed up?
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hi there not been on here a while but the fault you describe does sound similar to what i had id be changing the psu caps first then go for the lvds board if no joy rgds dave
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panasonic is the maker
fm is the series
these are good low esr caps
all i use nowdays
as some unit will only work with low esr caps if you fit standard caps in there place unit may not work or give short life
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hi
you read his post you will find psu working no fault when
connected to another tv just check
dave
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Hi,
The usual cause of this effect is either faulty electrolytic capacitors, on the signal PCB,
or the image processing IC, (this is the IC thats feeds it outputs to the LVDS cable).
Try using the hairdrier, but shield various parts of the PCB with a piece of card, trying
to localise where the heat has the most effect.
Check the LT supply voltages when the fault is evident, and again when it clears.
If you have a 'scope, also check for noise on the LT lines.
Regards,
John.
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Hi,
The usual cause of this effect is either faulty electrolytic capacitors, on the signal PCB,
or the image processing IC, (this is the IC thats feeds it outputs to the LVDS cable).
Try using the hairdrier, but shield various parts of the PCB with a piece of card, trying
to localise where the heat has the most effect.
Check the LT supply voltages when the fault is evident, and again when it clears.
If you have a 'scope, also check for noise on the LT lines.
Regards,
John.
I have noticed that using a hair dryer to warm the internals reduces the time taken to turn on to 3-5 minutes, from 20-30. Will definitely try the suggested method to localise the fault. Thanks.
By the way, I just changed all the aluminium capacitors on the PSU to no effect.
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Well this is weird. I have tried the method suggested watteu, using a hair dryer to warm separate parts of the boards to localise the fault. And while heating the area around the video processor and slightly below it, the video came on. What is unusual, is that even after being turned off for more than 12 hours, the tv turned on fine, with only a slight brightness flicker on the top half of the screen for the first minute or so.
I'll be leaving the tv as it is until it stops working again, as I don't have any means to diagnose it while it's working. Although if anyone can offer any insight into what happened, please share.
Thank you, everyone, for being a huge help. :c017:
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When you say video processor do you mean the T-CON?
The T-CON is the small board situated at the center top in your picture with the foil tape on it and has the cable labelled LVDS running to it.
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got boards for sale for this model...
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Hello again,
I come back for your help again with the same TV. The problem is still unsolved as I didn't have a chance to replace the t-con LVDS V260B1-C03 board (however I found that warming up the area around the t-con board with a hair dryer brings up the picture in a minute or less), until now. I've picked up a replacement board and now I'm worried the TV might be dead. :17:
After installing the replacement board and powering on the set for a test the picture was very dark, only the shapes of menus could be made out (didn't have any source connected). After maybe 30 seconds, the picture started to clear up, but i noticed a thin pillar of white smoke rising from the very top. Power was immediately unplugged and the TV was torn down, again, to find the source. Upon inspection I discovered that two components on what I assume is the LCD controller (long, narrow PCB, sits on top of the lcd, model no. V260B1-X03) have failed. Here is a picture:
(http://i.imgur.com/bL5NY.jpg) (http://imgur.com/bL5NY)
The failed components marked in red. Sorry for the poor quality, only have a phone camera. Not sure which markings around are relevant to the components. The components seem to have some numbers printed on them, but I can't make them out since they are darkened by the failure.
Now I have a few questions that I hope you can help me find an answer to. What exactly are these little components? Could they have been causing the original problem? If not, could a faulty replacement board cause these to fail? If for whatever reason the components can't be replaced, can the whole board be replaced? A google search with the model name does not turn up anything useful and the service manual I have does not cover this board.
For now I am left wondering if I killed the TV and looking forward to any replies.
Thanks.
Paulius
Edit: After more searching it seems that those are SMD fuses that failed. Anyone know what the specs for these fuses are?
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they look like decoupling caps, remove them and try the set again, you may find it works if the fuse hasnt failed
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they look like decoupling caps, remove them and try the set again, you may find it works if the fuse hasnt failed
Just did a google search on what a decoupling capacitor is as I've never heard of them before. From the few pictures that turned up they all seem to have a brown-ish centre, like the ones immediately to the right of the circled ones. The components that failed look more like SMD's, the centre seem to have been black even before they got cooked.. But then again I have no real experience with things like these and am only comparing to similar pictures found on google.
Either way I guess there is nothing to loose by removing them, if they are SMD's, the circuit is already open and there will be no change. If they are decoupling caps, it might just work again. Did I understand this correctly?
Thanks.
Paulius
Edit: Tried to put it together as it is. Good news - it works. Bad news - no colour blue. Still hoping to fix it if anyone can identify the components needed.
Edit[2]: Might be wrong about a missing colour, now it looks like a negative photo. Can this be changed back?
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Would anyone know where to find a schematic of the V260B1-X03 (MS35-D015438) board?
The two dead components are SMD resistors and at the moment both are at around 22 Ohm. It seems like originally they had a higher resistance, but after going up in smoke the numbers on them are unreadable. They are marked R4 and R9 on the board itself.
Or maybe someone has a V260B1-L03 Rev. C2 LCD panel and could check the values of these resistors?
Thanks.
Paulius