Thursday, September 8, 2011

4H.V1838.401 inverter hacking for Insignia NS-LCD37 LCD TV

This is a quick post for all the poor suckers who are trying to find 4H.V1838.401/D for a reasonable price.

I know how it feels, I was one of them myself when I bought a malfunctioning Insignia NS-LCD37 for $25 and diagnosed it with band inverter.

Well, at the time of writing this there weren't any good replacements to be found, not for a decent price anyway.

You could buy the transformers on eBay for $25 per piece, but I would have needed at least two PLUS at least two FETs that I found shorted and God only knows what else. That's easily $60, not to mention the FETs weren't available anywhere either and I would have to find and use substitutes...

This was easily a bad proposition so I set out to searching a replacement rather than repairing the inverter. You don't expect to pay more than $60 for a 37'' LCD inverter least I don't and you shouldn't either.

In fact, I paid even less since I happened to have one handy.

Only it wasn't 4H.V1838.401/D.

It was 4H.V1448.481/C1 used in the next Insignia model, NS-LCD37-09.

Which is a totally different beast altogether, but that's another story.

The point is, while not an exact match, it is widely available, cheap and does the job!
What more could you want?!

Ah, pictures...right:

Here are the two inverters next to each other:

The first problem, as you will see, is that the connectors for the CCFL wires are different sizes:

This is an easy problem if you use good cutters. Just cut in half all connectors, including the one for the common ground which is at the corner of the board:

It's really as simple as that!

The next problem you'll encounter is that the new board is slightly larger than the original and doesn't fit the borders made by the little metal plates at the two ends.
I just bent those a few times until they broke and then put tape on top to make sure they won't short:

The great news is the main cable doesn't require any changes at all, it just goes straight in:

Next, of course, you'll need to tweak a bit the metal shield (if you opt to install it at all) so that it can do some decent covering and allows for fastening with bolts. A little tweaking with pliers goes a long way:

Finally, you won't be able to use most of the fastening bolts, but you should be able to use at least three, which is more than sufficient for steady positioning.

I didn't take a picture of the working TV since it sold and went out before I could make that extra shot.

And if you wonder how did I know all that in the first place...well, that's just how I am.

Modesty comes first, of course.


Various Pictures said...

What are the mosfets model next to the big connector? thanks

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