Surface Mount Fuse Type? Fast, Slow?

[blhagstrom]

Hi folks,

I took the leap on a dirt cheap 46 inch Sony Bravia since I'd heard many flat panels have simple fixes (and there is a return period).

Research told be its a screen fuse issue.

Got the fuse identified and verified bad, valued (3A) and sized (about 3mm X 1.x mm).

Now, what type do I use to replace it.

Fast? Slow?

[drussell]

That depends on what circuit it is used in.

It's highly unlikely (but possible), though, that the fuse is the only problem. It was probably murdered by a shorted component farther down the line.

Have you checked everything it feeds for shorts?

[dr.ido]

Seconding that you check for shorts. If the blown fuse is on the backlight inverter board you'll probably find a shorted FET or 2.

I just use whatever fuse I have with the same rating even if the size isn't exact - pulling parts of scrap boards is quicker than ordering replacements for me. If you are ordering then though you may as well get this same size - just order a few just in case.

[blhagstrom]

Its supposed to be a known weak point in this model.
The fuse just lets go. (heat?)

I don't have those sorts of spare parts lying around.

I did jump it with a DMM and its passing 1.3A (its a 3A fuse). The screen lit up fine.

SO, I ordered both quick blow and normal blow fuses. It would be nice to know which one to stick in there. I'd like to at least do it right the first time given how heavy it is to move around and how many screws there are to get in there. AND the delicate soldering its going to take.

[drussell]

Originally Posted by blhagstrom

I did jump it with a DMM and its passing 1.3A (its a 3A fuse). The screen lit up fine.

If it is only doing 1.3A and it's a 3A fuse, it must die due to some start-up current surge or something being hard on the fuse so I'd use the slow-blow. It will still blow if there is a short or something but is less likely to fail on the surge current.