Magnavox LCD TV Repair

[mlensing1]

the power light is coming on and there is no sound and the screen is blank. What do i do?

[commando7144]

dam ur smart iv`e been into everything except solid state

[golf2002corsa]

hi there i have a lcd 32" tv when i turn the tv on and the screen comes on but no picture and some times it flickers. how can i fix it. thanks

[saschiver]

i have the same problem with my 42 lg3000. so it can be this?

[madisonelectronic]

I will name you the Homer L. Davidson of YouTube. Haha, I am such a smartass.

[dudueveret]

Hi.I have the model 5mf605t/17 magnavox lcd tv 15'',the sound is good,but not picture,they say fuse 150,what's it?for real?can you help me?tks!

[linagee]

The voltage supply is likely switched on and off by the microprocessor in order to do a low power mode. (To meet certain regulations that say a TV must consume under a certain amount of electricity when off.)

[86Alejandro]

Hello, nice video, just have a doubt, what's the model of the mosfet u changed ?? You just say tiny little 8 pin chip, but i think i have the same problem as you did. Pls bro you're gonna save my life. Bye

[Maxxarcade]

@86Alejandro I'll have to look in my paperwork to see what I ordered.

[86Alejandro]

@Maxxarcade ohh ok bro, thanks the thing is that i dont have any of the papers of the tv, i tryed to find the diagram on internet but nobody has it. Also I saw some datasheets of the most comun, but I dont wanna put some with dif characteristics. Thanks bro

[007foppe]

wat the hell is a mosfet lol i even try googling it im to stupid -_- they trow very big words at you like Metal-Oxide-Semiconductor Field-Effect Transistor and expect you to understand it 0_x

[taftdavid]

Best technical video I have seen. It would have been great if you could have actually traced the signal with a scope, and the use of a schematic to show how you determined the IC was bad.

[Maxxarcade]

@taftdavid I didn't have a schematic, or else it would have been a lot easier :-)

[orbiter8]

Great tips here, thanks for taking the time to show us. Much appreciated.

[carlanton593]

i have a samsung 19" monitor when i try to turn it on the power on it just keeps going on and off

[anike24]

i just have one question, how did you get it open. i have removed al the screws even the annoying ones tugged away. yet i still can get it open

[Mr888utube]

Hi Dave

I have a 42" Magnovox plasma TV having problem with power won't stay on. The green light come on for a light a second or two then couple click and went off. I've check all bad capacitor then replace it still no luck. Now, I'm thinking of replace a power supply board. But not sure if that's the root of the problem. Can you give me a hint or other possible way to diagnose it before make a power supply purchase. Anyhelp with greatly appreactiated. Thanks

[MultiIPwnage]

Thanks, I had a LG with the same problem and I did some research and it turns out it was the same thing that happened to this one, I got it to work!!!, its a 26" LG 1080p

[Maxxarcade]

@MultiIPwnage Sweet, that's a good TV to fix. I don't even have any 1080p capable displays yet, other than my PC monitor (2560x1600).

[GrantsPassTVRepairs]

How did you know the mosfet was bad?

[Maxxarcade]

@GrantsPassTVRepairs Had input voltage and gate drive, but no output. And since it was being used as a switch, I temporarily bypassed it with a jumper and the TV worked.

I have a Dell TV with a similar problem, but I can't trace the circuit down without a schematic. The component layout is just too dense.

[GrantsPassTVRepairs]

@Maxxarcade

What I mean to ask was how did you know there was suppose to be 3.3 volts on two of those connector pins. Was it printed on the PC board or did you have a schematic? Thanks. Dave

[Maxxarcade]

@GrantsPassTVRepairs Had a schematic for a similar set with the same size panel. Also concluded that 3.3v should be there, because the traces went directly from those connector pins down to the mosfet. The ground and LVDS signals were present, but no B+. The panel behaved the same as if it were disconnected.

And I think when a panel has B+ and ground, but no LVDS, the screen stays black. That's the situation I have with a Dell LCD I'm working on. I wish I could find a schematic.

[GrantsPassTVRepairs]

@Maxxarcade Good work and a very educational service tip. I appreciate you taking the time to share this.

Dave

[MrTonyshit80]

So what the problem..? I never see you have replaced anythings....? pls tell me the actually problem...

[youtubasoarus]

Nicely done. Very impressive.

[tokyoseoul1984]

Very helpful for me to understand what is going wrong with my TV. Thank you!

[commonwealth77]

Sorry for bugging you...I just read your info page and saw that you don't care too much about helping others, which is fine. You're probably a busy guy. I mainly work with CRTs and just thought you could help me 'cause I'm new to LCDs.

[Maxxarcade]

Check the voltage at the power input jack and see if it sags a lot during power on. If so, you need to work on the AC adapter. If that is good, then there are quite a few things on the main board that could cause that problem. Are any caps bulging?

[commonwealth77]

I've got 12 volts coming from the ac adaptor. I did find one cap that was questionable so I changed them all. I'll check the voltage reading after the power supply section and see what I've got. How much was the ic that you replaced?

[commonwealth77]

I've got the same model, but I don't have audio or backlight. Could that mosfet be killing it or should I look in the p.s. section? I've got power to the power led. What do you think? High temperature cap?

[Huzziii]

my LCD tv turns white when i turn it on and i gotta keep turning it off and on to make it work, i have sound but no picture????? eventually after 10 min its fine....

[maynardcat]

Very impressive work. You have to have the proper training and know what you are doing for circuit tracing problems with small micro chip circuitry. I did replace a tiny part on a mother board once, and it turned out ok, but I wouldn't say I knew exactly what I was doing.

[vadim935]

hey thanksfor the video. i have a magnavox 15' lcd and when i change chanals the back light only stays on for 3 secconds, then turns off , do you know what could be the proble,m ? thanks

[chrisstv1979]

I have a 15" LCD polaroid that has video for 3 seconds then goes out. The audio is distorted. Replaced caps in power supply and no luck. Is it the video board?

[Maxxarcade]

It's hard to say what could be wrong without having it in front of me. You may have other bad components besides caps.

[chrisstv1979]

I checked the B+ voltage on the pins that plug into the video board. I got 5 volts on one pin labled 5 volts, and 12 volts on another pin labled 12 volts. My powersupply appears to be functioning.

[Maxxarcade]

With most LCD's I've seen, there are usually some voltage regulators on the main board as well, such as 3.3v, 2.5v, etc.

If you can locate the audio amplifier IC, you could look at the data sheet to find how many volts should be going into that.

[cpeny]

magnavox tv are junk especially the 37/42 inch tvs

[Maxxarcade]

They are made by Philips, which has been crappy for quite some time it seems.

It's getting pretty hard to find a brand that actually has good quality electronics anymore.

[Majorzzero]

Cool video, I have an old LCD screen that keeps loosing its VGA singal, after i have been on for some while, do you have any idea for what that can be?

keep up the good work :)

[JeffN727]

Great job on the repair.

My gosh, look at the chinsy speakers in that thing!

[Maxxarcade]

Ya, the sound is terrible on these types of TV's.

I miss the TV's from the 60's and 70's that had the huge speakers with the tube amps.

[youtubasoarus]

Damn that's awesome.

[batterymaker]

That chassis is so...alien...to me....I'm used to handwired metal chassis!

[AllAmericanFiveRadio]

Very nice job. Very interesting and useful too.

[retrochad]

That's really great work, I haven't ever tried repair on surface mount devices. Did that old MOSFET chip have a part number on it you could cross-reference to a universal replacement?

[stillfindingmyway]

Good work! I've replaced a few ICs of similar type in CD players with very basic tools like yourself and I can tell you that it's hard work! You can understand why so many people (including me) don't repair consumer electronics anymore....I know it is possible to work-out what a lot of components do on a strange piece of equipment through knowledge and datasheets, but did you have access to a circuit diagram in this case?

[Maxxarcade]

I had no schematic, just a datasheet for the part.

[myozone]

Did you have a schematic handy ?

[fozzyozzy106]

brilliant 5/5

[sinistermoon]

Good work man!

[weasel2htm]

A TV lives again, ... if you don't mind me asking how much did that chip cost?

[Maxxarcade]

If I remember right, it was under $2. The hard part was installing it without any special equipment... I don't even have a magnifying glass at the moment.

[ttwilightzzone]

Thanks for the great video!

[PRODVDi]

way cool

[umajunkcollector]

Was this a warrenty repair?

I suppose a new set like that would be about 300$.

[Maxxarcade]

Nah, it was made in 2004. I just fix stuff as a hobby, I don't run a business.

[fordbroncodave]

good work once again. did the resistor blow or did the silicon chip blow?

are there different tools for doing surface mount repairs? they do surface mount boards in cb radios now because of vibration issues in motor vehicles thus more reliable