Inspiron 640m - Invertor or Screen faulty?

nodgienodge

Hi

A few months ago the screen on my Dell inspiron 640m stopped working - it went very dim, started flickering, then went off, then it suddenly started working again for a few days, then stopped again, and never worked again.

I can still see the image on the screen if I look very carefully but for practical purposes there is no image.

I think it's either the backlight or the invertor that needs to be replaced, the problem is which one?

Alanstrainor

I'd guess it's the inverter. It's hard to be absolutely sure.

nodgienodge

well I haven't got a clue.
All I know was I was in a computer shop and the guy told me it was the screen cause he tried another invertor and said it didn't work.

However I smelled a rat, so I said: Ok, well u replace the screen but I want to keep the old screen (because it's mine)

He seemed reluctant because if he was to buy a replacement screen he'd be making a loss on this transaction and he had this idea in his head that he was somehow "entitled" to keep my old screen

So I told him to put the laptop back together and give it back to me. I may be wrong still but it's bugging me now because if it is the invertor I can probably fix it myself.

Alanstrainor

nodgienodge wrote: »

well I haven't got a clue.
All I know was I was in a computer shop and the guy told me it was the screen cause he tried another invertor and said it didn't work.

However I smelled a rat, so I said: Ok, well u replace the screen but I want to keep the old screen (because it's mine)

He seemed reluctant because if he was to buy a replacement screen he'd be making a loss on this transaction and he had this idea in his head that he was somehow "entitled" to keep my old screen

So I told him to put the laptop back together and give it back to me. I may be wrong still but it's bugging me now because if it is the invertor I can probably fix it myself.

If you can fix the inverter you can replace the screen. You'll have to completely open up the laptop to get at the inverter, replacing the screen is only a few more screws away.

Magown3

I'd be 90% sure it's the screen. It usually is when the backlight goes.

The guy in the shop might be returning your screen to get back some money for the defective one. Obviously it depends on a lot of things but your nose will tell you if he's genuine or not.

Screen replacement should'nt be much harder than the inverter TBH. Just make sure you don't damage the lcd cable at the back when removing the screen.

maki

Considering you can still see an image with no backlight I think you can safely rule out the screen being at fault.
The CCFLs used in backlights are rated for on average 50,000 hours and even so are unlikely to simply die. Generally they dim to around half-brightness if they're on the way out.

An inverter problem is by far the most likely and is fortunately the cheapest part to replace.

IrishPhoenix

My laptop had the same symptoms before and it was the invertor.

nodgienodge

Just ordered a new inverter on ebay

Ok well that all seems to make sense. I don't know what an inverter actually does but I calculated the screen would have been on about 5000 hours maybe. Moral of the story: Don't trust laptop repair shops. Ever