Plasma TV Recycled For Education
Ever since I have taken up electronics as a hobby, everyone seems to have a faulty electronic appliance.
I work for TAFE (Technical & Further Education) as an Automotive Lecturer and we are always looking at ways to stretch our budget. One of my workmates had recently been to the rubbish tip to empty his trailer of rubbish. Just like me, he came home with something as well. But instead of taking his goods to his house, he brought it to me! We had to sneak them in so my wife didn’t see!
He had managed to pick up 2 flat screen TVs, one is a Dick Smith GE6833 LCD TV, which is very difficult to find any information or schematics for and the other was a Panasonic TH-50PZ80A Plasma TV. I started with this one first.
When the power switch is turned on, the standby light flashes twice. I had never worked on a Plasma TV before, so I had much to learn. After much research on the internet and purchasing several EBooks from Kent Liew (thanks for the help Kent), I was able to trace the fault.
By disconnecting the mainboard from the power supply, you can isolate where the fault is. My TV refused to show a backlight, when the 3 connectors were removed.
The Three Mainboard Connectors Disconnected
This indicated a power supply fault. These also have a common fault with 15 Volt standby and also the V-SUS voltage.
By testing for 15V standby at connector P7, Pin 1, I could see that during switch on, I had the necessary voltage. However, when testing for Vsus voltage (190V) at connector P2, Pin 1, only 2 volts were found – a far cry from the required 190 Volts!
Two almost identical circuit boards are located on the power board. The one shown on the left is a driver that switches the FET transistors, oscillating the transformer that supplies the 15 Volt standby voltage. The other is a driver for the Vsus Voltage of 190 volts.
It was time to get out my can of freeze spray! After freezing the Vsus IC, the TV operated correctly when switched on. At least I knew where the fault was…
I was able to purchase the kit I needed to repair the circuit boards. They come in a pack of two as both ICs are usually replaced at the same time.
Included in the kit are 2 electrolytic capacitors that are also replaced. These are surface mounted, but are much easier to fit than the originals due to their larger size.
A friend of mine had made me a 3D printed circuit board holder and I had found it very useful for repairs that had done before. This time it proved invaluable.
I reassembled the TV, switched it on and to my surprise, IT WORKED! I ran it for about 8 hours to test it thoroughly.
I will now pass it on to our TAFE College for use in a classroom. Saved from the rubbish tip – I’d say that’s a successful repair!
Latest Update- 23/7/2015
I just thought I would show you what happened to the Plasma TV I repaired and donated to our local TAFE college where I work part time. We will use this TV on a trolley as you can see in the photo for use in the workshop to show students information, access the internet and also have programs loaded for oscilloscope, scan tools and other features.
I hope to repair a few other TVs for the campus to be put to use in similar ways.
This article was prepared for you by Mark Rabone from Australia.
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June 25, 2015 at 1:58 pm
Excellent job Mark, it was a pleasure reading your article. Thumb up.
June 25, 2015 at 3:29 pm
Thanks Mark for this Plasma TV repair article.
I still haven't seen any Plasma tv from the inside yet but since it was also your first Plasma tv fix, you must be very promising in repairing your next one!
I recently found a new problem concerning LCD Television screens that I had never heard before and is very hard to repair at home. And that is Shadow forming, if that is the correct English expression for it.
That problem occurs when the LCD polarization Folie inside the LCD isn't stretch flat over the whole screen but gets kind of wrinkled on the edges or on other positions. Creating that the white Backlight isn't equally white on the whole screen anymore and produces unwanted greyer darker "shadows". On YouTube there are people showing how to remove these shadows spots by using cold turkey from the freezer (REALLY!) by pressing it for about 30 seconds on those spots. Normally we need a clean room to repair our screen when opening the inside to prevent static dirt particles getting on the folie. But this shadow effect is something I recently noticed on my about 6 year old Samsung 37 inch LCD TV. Since it was only a Stripe about 4-5mm wide going vertical from top to almost bottom, in the outer left side of the screen, I won't open my tv for it. Not making it any worse by opening it. And also because I'm not sure if I'm able to fix this.
June 26, 2015 at 6:46 am
I understand how you feel & I had no idea what I was doing until I started. Can I suggest looking at YouTube for the model and fault?
I have seen repairs done by taping down FPC (Flexible Printed Circuit)or adding packing to hold pressure on it. While that may not be a permanent fix, at least it points you in the right direction.
There are so many helpful suggestions that can lead you in the right direction. Also, there are heaps of excellent Ebooks listed here on Jestine's site that can help you gain confidence before you start.
I certainly don't claim to be an expert, but I now have more confidence to crack open an electrical appliance when it needs repair. Learning is an experience, a journey, motivation and just plain good fun!
Keep up the good work!
PS - not too sure on the cold turkey - unless you want it for lunch!
June 28, 2015 at 6:09 pm
Thanks for your thoughtful reply Mark. When I find a promising solution for fixing my Samsung's "shadow" problem I surely will take the effort to try it out. But I haven't found any clue on how to repair it on the internet. The Cold Turkey didn't work on my Samsung tv. But I was thinking to place my tv outside on my Balcony in a month or 6 when Winter begins. Maybe that does do the trick. That is also the time when I normally clean out my Refrigerator, by shortly placing the foods from the fridge in the freezing outside. The fact that I haven't repaired a Plasma tv is because I know no one that ownes one. Most people here own LCD tv's.
June 29, 2015 at 9:25 am
You might find it a better option to use freeze spray as you can isolate the component at fault. A cold turkey (that usually means something else...) because of it's large surface area may fix the fault for a certain time, but will not direct you to the faulty individual component.
June 29, 2015 at 5:34 pm
Dear Mr. Mark
You did great and Good work.
thanks you for sharing your expertise.
Amir Mukhtar Ashrafi
June 25, 2015 at 3:39 pm
Nice repair, Mark. Good job saving the TV from the dump.
June 25, 2015 at 4:57 pm
Thank you Mark, it is a pleasure to read your article.
Hope to hear more from you.
June 25, 2015 at 5:13 pm
Well done Mark,
People either throw these out or give them away as the cost of repair is prohibitive which is a shame really
when a tv or other appliance can be saved to enjoy for a few more years yet ! I've come across a few of these
myself and it's a good feeling to help do our little bit for the planet and either it can be kept, given to someone
needy or maybe sell it for a small profit. Thanks for sharing the article and the photos were great !
June 26, 2015 at 6:51 am
The rubbish tip is my favourite place to visit - apart from romantic walks with my wife of course!(Is she reading this right now???)
You are right, so many people just see a faulty item that needs to be thrown away & yet we see it as an opportunity to test our skills, to expand our knowledge, to save another item from the rubbish tip and help the environment. In the end, I usually just give the appliance away to someone who could use it rather than see it end up in land fill again. Still, it is definitely worth it.
Thanks for your comments
June 27, 2015 at 6:24 pm
Hi again Mark,
Recycle days run by the local councils are more gold mines to be had.....the suburb next
to mine is having one starting tomorrow and already there is loads of stuff that looks very
interesting and begging to be worked on. I am nearly running off the road when driving
past it all as I'm having an "optic nerve" but I just need to find a way to sneak some of it
home past the Mrs.....lol
June 28, 2015 at 3:24 pm
I reckon it takes just as much skill to sneak it past the wife as it does to repair the item. Us recycle guys have to stick together!!
Our hard rubbish week is coming up in a month or so and I already starting to drool.....
June 25, 2015 at 6:29 pm
very interesting article. very informative. thanks for sharing. God bless you
June 25, 2015 at 7:53 pm
Excellent repair and nicely described, congratulations. It is always wonderful to see equipment saved from the rubbish tip.
Regarding junk, wives have a different perception than we do… for me junk is something I don’t need until the day after I threw it away 🙂
June 25, 2015 at 9:16 pm
I couldn't agree with you more! Our wives just don't understand our unrealistic obsession with collecting things that clearly have no use for now, but maybe, one day, in the distant future could save us a few dollars. Then we get to say "See, I knew that would come in handy one day!"
June 26, 2015 at 4:28 am
That is so true !....
June 25, 2015 at 10:16 pm
Hi Mark Rabone, you have done a great repair, I worked in Education some years ago.
June 26, 2015 at 4:59 am
Mark thanks alot i enjoyed.
June 26, 2015 at 5:51 am
Don a good job! Another flat screen TV saved from junk.
I like how you are explained the stuff and I wish you more and more
positive repair experience on TV field.
June 27, 2015 at 8:11 am
Somewhat unusual for the well built & designed Panasonic TVs to fail.
But that was a great save.
Even if I knew the ICs were faulty I would have been fearful of attempting replacement. Yes I know there are Utube vids about this, but they all feature advanced skills. My hands just start shaking when precision is needed.
June 27, 2015 at 11:30 pm
Great fix mark and thanks for sharing!
June 29, 2015 at 5:35 pm
Thanks you for Sharing Expert Views to learn and get success.
Thanks you Again
Amir Mukhtar AShrafi