Smd fuse replacement

[audiofreak19]

Ok so I have a smd fuse 3a on a main board I have that needs to be replaced. I don't have any extra ones but I do have a 5a laying around. Would it really be that bad to put the 5a in place of the 3a. Or do I need to order a 3a.

[paulstef]

Re: Smd fuse replacement

As long as everything works fine you can even put in a 200A fuse. Or a nail. :-)

I would always avoid replacing them with others having higher current rating.

[audiofreak19]

Re: Smd fuse replacement

Haha. I might just do it anyway. I'm hoping it will fix the problem w/ the main board.

[Thomas Capper]

Re: Smd fuse replacement

I have seen various warnings in tv's, home electricity, and car fuses that you should always replace the fuse with the same type/amperage.

[paulstef]

Re: Smd fuse replacement

Haha. I might just do it anyway. I'm hoping it will fix the problem w/ the main board.

Ah, ok, you still have a problem with the board? In that case do not replace it with a fuse with a higher current rating. It gets damaged for a reason. You may end up damaging traces if you pass too much current through them.

[audiofreak19]

Re: Smd fuse replacement

Yea it still didn't fix the problem. I'm almost completely exhausted on this tv. I checked all fuses for voltage. All caps good. All points on power board getting correct voltage. I have no idea where to go one this one. The heat shield on the main board still gets kinda warm. Not so warm it burns but enough to notice. The tv is a m550nv vizio that when plugged it logo flashes for a while then goes to stand by. U turn it on and the backlight turns on but no picture on screen. If u hit the power button to turn on menu the screen dims but no image.

[paulstef]

Re: Smd fuse replacement

Ok, so something draws too much current. You don't happen to have access to infrared camera?

[audiofreak19]

Re: Smd fuse replacement

No I don't. Left it in my other spy bag. Lol jk. But originally I had to replace a melted capacitor that was underneath side of the main board next to where the heat shield would be.

[paulstef]

Re: Smd fuse replacement

Do you have the service manual, schematic? Do you have an oscilloscope?

[audiofreak19]

Re: Smd fuse replacement

I dot think they have a service manual for it. And I only have a dmm

[paulstef]

Re: Smd fuse replacement

Can you post a pic of the region where u said you replaced a melted cap?

[audiofreak19]

Re: Smd fuse replacement

K

[audiofreak19]

Re: Smd fuse replacement

Here's another

[audiofreak19]

Re: Smd fuse replacement

This was before I replaced the smd cap

[paulstef]

Re: Smd fuse replacement

This was before I replaced the smd cap

So somebody already tried to repair the set before you did?

It doesn't look "melted". Was it shorted? What is it connected to? VCC GND etc?

[audiofreak19]

Re: Smd fuse replacement

I don't know what it was connected to but the last picture showed the plastic part melted down. So I replaced it but did a real bad solder job.

[paulstef]

Re: Smd fuse replacement

The cap on the last picture has very likely not been mounted like this in factory. Somebody replaced it already. Was it shorted?

You can determine what it is connected to when you follow the traces back to the power supply. I assume it to be on GND on one side and on 3V3 or %V on the other side.

[audiofreak19]

Re: Smd fuse replacement

I wasn't sure. I don't have the board infront of me right now. Before I replaced the cap the tv wouldn't even power on or have the logo light up. And after I replaced it it will turn on but no image.

[paulstef]

Re: Smd fuse replacement

Measure the voltage on that cap. Multimeter first DC, then AC. Post the results.
If possible get a scope borrowed from someone.

[audiofreak19]

Re: Smd fuse replacement

K