Samsung 940B

[frostpuppy]

Hi All,

I've got 4 x Samsung 940B's each with different symptoms.

1 works perfectly! Yay
1 has the 2 second display issue, which you can trigger by pressing the "return" key to change video modes (Digital to Analog) and you get to see the input signal for 2 seconds before black screen.
1 flashes its little blue power LED/button but doesn't do anything else
1 is dead like a dodo. No noise, no indicators at all.

I guess the first place to start is to pull the covers off and start looking for visible faults. I've never dismantled a LCD display before but I've previously worked on CRT based displays. Anything to watch out for?

I'm assuming it may be faulty caps, any particular caps to look at / for?

Regards

- Simon

[lexwalker]

Re: Samsung 940B

I've got 4 x Samsung 940B's each with different symptoms.

1 works perfectly! Yay
1 has the 2 second display issue, which you can trigger by pressing the "return" key to change video modes (Digital to Analog) and you get to see the input signal for 2 seconds before black screen.

Could be bad transformer. This one may require a lot of components checked if the transformer isn't at fault.

1 flashes its little blue power LED/button but doesn't do anything else

Very likely badcap problem. Worst case scenario would be Dscaler board failure (e.g. firmware problems)...

1 is dead like a dodo. No noise, no indicators at all.

Can be many things wrong there, ranging from fuse, failed power supply section to faulty Dscaler board.

I guess the first place to start is to pull the covers off and start looking for visible faults. I've never dismantled a LCD display before but I've previously worked on CRT based displays. Anything to watch out for?

I'm assuming it may be faulty caps, any particular caps to look at / for?

Just the signs of bulging and check for the ability of the capacitors to charge. Also look for shorts in the most obvious areas (diodes, MOSFETs, etc). Those are just the first steps...

[R_J]

Re: Samsung 940B

I just had a Samsung 940b That would light the backlight up sometimes and sometimes not, there would be a bit of an high voltage arc sound (sizzle)and it would go dark. I thought it was the transformer but it turned out to be the backlight ccfl's themselves, in this case the lower ones (there is one pair at the top and one pair at the bottom of the panel) both lower were cracked in a couple places but would somehow stay lit once and a while. It also had bulging caps in the power supply