LCD TV Repair made easy # 12

[imaginashawn]

Can't seem to find TV LCD replacement screens here in the states ... is that because they cost too much to be worth replacing?

[linagee]

For this TV: power supply repair service listed on ebay: $90, used power supply listed on ebay: $145, new non-ebay supply: $235-$275, SAMS sheet: $32 to $37 hard copy or $20 to $25 electronic only. Repair service minus electronic manual = $65 to $70. So you can save or value your work at the price of $65 or $70. Nice. :-)

[imaginashawn]

@GrantsPassTVRepairs

Thank you Dave for your guidance. I have decided it would be a good idea to learn all I can about Mode Switching Power Supplies. I've searched around and found some grate sites to learn this and more for free, which is a blessing for a guy on disability!

[imaginashawn]

Thank you Dave for your guidance. I have decided it would be a good idea to learn all I can about Mode Switching Power Supplies. I have found some grate sites to learn this and more for free, which is a blessing for a guy on disability!

All these sites are free!

[GrantsPassTVRepairs]

@imaginashawn Yea the Internet is full of free stuff. Learning all you can about switch mode power supplies is a good place to start.

[imaginashawn]

@GrantsPassTVRepairs I would have shared the sites I found but UTube won't allow it. Let's see if I can outsmart the robot: williamson-labs com is a grate one.

[GrantsPassTVRepairs]

@imaginashawn It worked. Thanks.

[waterinawell]

great tips especially with the meter prongs slipping when taking voltage readings at the pads..i have a polaroid tv where left half of the screen has a greenish layer to it and the picture is slightly distorted on that side.. it sometimes goes away after having turned on for 10-15 mins but comes back if i restart the TV....any clue what board might be responsible? it happens on all the video inputs..have you had any problems with BGA packages getting bad solder joints after some time dueto heat?

[jenko701]

Great video ,What I like to do ,and would make good video , is show how to jump start a power supply by it self with out it being in a set .Then you can tell fast if the power supply is the problem or if it is not geting a start up signel from the main board . and if it is the problem you do not need the set in the way wile you are working on it. I do the same thing with back light boards . Put 24 v on them and a 3.3 v start signal if it lights you know you need to check the main board .

[imaginashawn]

Also thinking a short in the inverter could create a higher voltage draw for that one bulb ... am I making any sense?

[GrantsPassTVRepairs]

@imaginashawn Yes a shorted inverter transformer or driver transistor on the inverter board can cause a higher current flow, and this often causes the fuse on the inverter board to blow, but in such a case you will not have any back light at all. Sometimes just one transformer or driver transistor can go bad so only part of the back light will work, but I can't see how a shorted component would make the back light momentarily brighter.

[imaginashawn]

@GrantsPassTVRepairs

The second symptom (bright flash and then off a few seconds) was apparently caused by power surges (I live in a large apartment complex). In moving things around a couple days ago, I accidently plugged the TV straight into the wall thinking it was something else. TV back on surge protector solved this part.

Original problem (so bright on right side when first started that picture color is washed out and you can see the grid in the screen) still exists.

[GrantsPassTVRepairs]

@imaginashawn I'm finding it difficult to believe it was a power surge problem even though the problem seem to decrease when plugged into a surge protector.

[imaginashawn]

@GrantsPassTVRepairs

Your right, it returned this morning when I turned it on. So, both problems are still there.

[imaginashawn]

Hi Dave,

I am really enjoying your videos and learning a lot! I hope you continue with them. I was watching a while back and then naturally became more interested lately when my own LCD TV started acting up (2 1/2 yr old). One of the back lights get way too bright in the top right of the screen ... once the set warms up it's normal. I've been watching for a hint on what this could be but so far I haven't seen it or missed it in your videos. Any thoughts? Thanks, Shawn / Imaginashawn

[GrantsPassTVRepairs]

@imaginashawn I have heard of a bad capacitor on the inverter board causing one of the lights not to be as bright, but I have never seen one glow to bright. Could it be that one of your lights is to dull so the other one just seems to bright in comparison? When the light first turns on it requires a higher than normal strike voltage to get it started, but then it drops down to its normal operating voltage and becomes a bit brighter as it warms up.

[imaginashawn]

@GrantsPassTVRepairs Thanks Dave for your reply. To be more clear, when the top right gets too bright, it's so bright that it 'washes out' the colour. The left side remains normal all the time ... never changes. Just tonight, it has developed something new; a very bright white flash and then the whole monitor goes black for just a moment, then it returns to normal. Seems more and more like an inverter board right?

P.S. You have a book? How do I get it?

[GrantsPassTVRepairs]

@imaginashawn No I wouldn't assume it's an inverter board problem although it could be. Bad inverter boards are more likely to cause a dark screen or a partly lit screen. When you mentioned a very bright flash before it went dark it didn't sound like anything I have ever seen.

[imaginashawn]

@GrantsPassTVRepairs I'm sensing learning a lot more about Switching Power Supplies would be a good move for me. Might come across my TV's problem while I'm learning to! Seems like the new symptom is the old one just increased. Like too much voltage to the back light making it brighter ... and now the voltage is high enough that the protection circuit shuts it down for a moment. But like you say, better to learn it than to guess though.

[howrard]

Thanks for the reply Dave ! I have a set like this. no pic no sound I replaced some caps an still the same.Guess I will just remove my new parts an trash it. if you had trouble with all of your experience ( I have none ) but I enjoyed giving it a try thanks for your videos Howard

[GrantsPassTVRepairs]

@howrard Sorry your attempt didn't bare fruit. Unfortunately that's the way it goes sometimes. Dave

[howrard]

Hi Dave, were you able to repair this set ? If so what did you find wrong ? Are you saying that the schematic didn't help you much in this case ? Howard

[GrantsPassTVRepairs]

@howrard I don't think I fixed this one. In this case I found the sams manual was missing some voltages.

[Pokemonfanic56]

Found a control panel with power supply for my Polaroid . Do you think this would fix my problem? I am the one that was trying to use the VGA mode and my TV never woke up.

[untouchable36046]

hi Dave i got the new T-con board yesterday and installed it but that did not fix the problem come to find out it was the LCD panel needs replaced

[GrantsPassTVRepairs]

@untouchable36046 Unfortunately bad displays are pretty common. Thanks for letting me know.

Dave

[GrantsPassTVRepairs]

@untouchable36046 I can't say if replacing the t-con will solve your problem. If it does please let me know

[GrantsPassTVRepairs]

@untouchable36046

I doesn't sound like a power supply or an inverter problem but I can't guess at what it is based on the symptom you described.

[GrantsPassTVRepairs]

@untouchable36046 If you look at my website you will find a place that sells schematics. TV REPAIR INFO . COM

[GrantsPassTVRepairs]

If you check my website you will find a place that sells schematics It's at TV REPAIR INFO

[haroldrahl]

hi there sir dave, most of my customers here have conventional CRT tv, so if you have tips on OLD CRT tvs I would greatly appreciate it, LCD tv are for those who can afford it, LCD tv cost a lot here in philippines, the smallest LCD tv here (14" or 17") cost at least 4,500 pesos, the big ones(32") cost x10(45,000 to 60,000 pesos) so poeple here buy only those conventional CRTs

[GrantsPassTVRepairs]

@haroldrahl Here in Grants Pass Oregon they don'tsell CRT TVs in any of our stores. As the price keeps going down I'm sure your going to start seeing more of them in the Philippines.

[rkhajaxxx]

Hi thanks for reply. I just found out it's the main board that's defective with part# 1-876-406-11. 'hope to find part thru internet. Thanks once again!

[GrantsPassTVRepairs]

@rkhajaxxx You might try ebay. Just make sure the seller has good feedback.

[rkhajaxxx]

I have a problem with my SONY bravia KDL 32M4000. It quit working suddenly. When I turn it on, the POWER light comes on and the screen is back lit with no picture or sound. I took it to the video shop and he said that the VIDEO MODULE is defective and I guess he changed some parts on it and it worked fine for a day and then it's back to the original problem again. Would changing the whole Video Module fix the problem? Thanks for you advise!

[GrantsPassTVRepairs]

@rkhajaxxx I don't know what a video module is unless you mean the video processing unit. It's not good for me to guess at what caused your TV to fail with out doing tests first.

[1JCRR]

Hi, in my case I got a solid standby red light, The tv will turn on but if I turn it off I have to wait sometimes a few day for it to work again, I can leave it on for weeks it will work fine. Could it be a power supply issue? I believe it is a re-branded Polaroid, it is an Element FLX3711B, power supply is 860-AZ0-JK371H.

I did pull the power supply out and weird enough, after I placed it back in it turned on and off just fine but after a few minutes it started doing the same, remote is ok.

[GrantsPassTVRepairs]

@1JCRR There is a good chance it's bad capacitors in the power supply but you can't always tell just by looking at them. Did you watch my videos on ESR capacitor testers?

Dave

[1JCRR]

@GrantsPassTVRepairs Yes, since I do some electronics repair as hobby I ordered one... Hmmmm just noticed hdmi is not working but exterior antena gets video... BTW there are two hdmi ports inside but one is not exposed (TV is advertised with only one...) Thanks again!!! "You da man!"

[stevehoughton]

awesome videos Dave, thank you.

[mickeygovender]

Good Tips Dave.

[juopotski]

Good tips! Keep these videos coming!

[quirmche]

I appreciate your down to earth explanations and tips and tricks. You really seem to enjoy the diagnostic portion of the repair process. Also, your explanation of the basic functions surrounding the SMPS was insightful. Keep up the good work!

[GrantsPassTVRepairs]

@quirmche Sometimes it's lots of fun but there are difficult times when I would rather be digging ditches. LOL Thanks for the comment.

[RAYGproductions]

Good info thanks..

[ibanez1357]

I noticed your 3.3 volt reading (on/dim) was low, from my experience that indicates a main board problem, And since that particular voltage passes through the power supply and goes to the inverter it would explain why the set won't turn on.

[GrantsPassTVRepairs]

@ibanez1357

Sometimes the stand by voltage is normally less than 5 volts so I didn't figure there was a problem but I appreciate you input. I did check all the regulators on the main board but they tested good. I used an identical power supply from a different set and it worked, but when I use own power supply it has a symptom identical to what you would see if an inverter board was bad. Sams sent me an incomplete schematic so I'm a bit frustrated on this one.

Dave

[ibanez1357]

@GrantsPassTVRepairs

Cool I guess that means it's the power supply and I was actually refering to the 3.3 volts that comes from the main and controls the on or dim (backlights), I noticed you wrote on your paper that it was low.