Mr Whippy
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| posted on 20/8/12 at 10:53 PM |
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Help needed with broken plasma TV
Hi you lot
I was given this tv a Panasonic TH-42PX60B Plasma, as you can see the screen is a bit weird!
 I was hoping I could fix it somehow and in the process learn a bit about these new tellys. I've been reading up on them and kind of get it,
the most common prob seems to be horizontal lines being blacked out and these are caused by the y-axis side of the circuits, I have even pulled out
the ribbon cable on the sides (blue box) to prove this, apart from being a right sod to get reconnect properly, removed these did indeed just make a
black line across the screen.
But as you can see I have a kind of vertical lines or bars where half seems to be working (static shown in this pic) and the other not changing at
all. I was thinking this may be the x-sustain board (red box) as it is very similar to the y-sustain board (green box) though not identical. What the
four connections are on the right I have no idea, they have no individual wires in them like the other ribbon cables but I believe the x-sustain board
is connected via the arrowed lead to the x-buffer board/s (orange box but I can’t tell if it is one part or two) and that in my mind is dealing with
the vertical lines. Seeing that so much of the picture is effected then it appears the x-sustain board must be at fault rather than anything later on.
God I hope that makes some sense, it sounds like something out of Startrek... The boards are quite cheap I just don’t want to buy the wrong one.
Any opinions on the issue with this thing or am I on the right track?
Thanks  oh and yeah I've already had one bloody great jolt of this sod, now switching off to fiddle with it 
[Edited on 20/8/12 by Mr Whippy]
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wilkingj
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| posted on 21/8/12 at 08:13 AM |
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Be aware they can still give you a jolt even when switched off and unplugged.
Those big caps in the PSU will still drive the oscillators enough to give you a belt.
I hate switch mode PSU's. Nasty things to fault on as well.
Guess how I know!!
1. The point of a journey is not to arrive.
2. Never take life seriously. Nobody gets out alive anyway.
Best Regards
Geoff
http://www.v8viento.co.uk
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Mr Whippy
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| posted on 21/8/12 at 11:09 AM |
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quote:
Originally posted by wilkingj
Be aware they can still give you a jolt even when switched off and unplugged.
Those big caps in the PSU will still drive the oscillators enough to give you a belt.
I hate switch mode PSU's. Nasty things to fault on as well.
Guess how I know!!
cheers, I am trying to be careful and avoiding the capacitors or the ends of wires and cables
any idea on the telly prob??
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gremlin1234
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| posted on 21/8/12 at 02:40 PM |
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have a look at the electrolytic capacitors (in particular the black ones) and check the tops for bulges or leaks.
if any are failing, then simplest to replace that board,
though they (the caps) can be replaced individually. (but do all similar ones at the same time)
also the top/middle/left board has some discolouration, so inspect that too.
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bi22le
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| posted on 21/8/12 at 04:55 PM |
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My gut feeling would be the earlier the board in the chain will knock on faults to the other boards, similar thoughts as you.
Have a good look over the boards and take them out to have a look at the other side. Your looking for strange colours, burns, dismembered components
and signs of cracks at the welds. Some times using ice spray (or compressed air in a can) to super cool suspect components, including complex IC, can
bring them back to life long enough to diadnose or pin point a board. Worth a shot.
Also the way that I read your reasoning is the presented fault and potential problems board is uncommon to the norm. I would consider buying an
identical telly that is also broken and swap the components in and out to get one working telly. The scrap or sell of the seperate parts to get some
monies back.
I am no TV repair man but have fixed some very complicated electronic parts in the past and have no fear when attacking that sort of thing. Its
already broken, why not give it a go!!
Good luck.
Biz
Track days ARE the best thing since sliced bread, until I get a supercharger that is!
Please read my ring story:
http://www.locostbuilders.co.uk/forum/13/viewthread.php?tid=139152&page=1
Me doing a sub 56sec lap around Brands Indy. I need a geo set up! http://www.youtube.com/watch?v=EHksfvIGB3I
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Mr Whippy
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| posted on 21/8/12 at 10:57 PM |
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thanks certainly never thought of cooling it like that to see if it works, interested to give that a go
So far I've been over the board with a high power torch looking for fried components but will take the suspect board off and have a look on the
back side too
It's on £30 for a replacement board, very tempted to go for it anyway. I have seen a you tube clip of the same kind of set with exactly the same
fault but they do not say what it was sadly
Although it looks really complicated when I first opened it up it seems to be just several large components wired together and as you say you can work
back up the chain to where one component would effect all the ones after it
Break it and sell the parts  I see a business plan there  well I'll try and get it going first just for the fun of it
Thanks for the help
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Autosri
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| posted on 21/8/12 at 11:04 PM |
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quote:
Originally posted by Mr Whippy
Break it and sell the parts I see a business plan there well I'll try and get it going first just for the fun of it
you still need to find which bit is broken though as you cant sell that board as its obviosly broken
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