samsung le32r87bd loses backlight after 3 secs

[charlierfc]

Hi all,i have the above samsung,the power going to the inverter seems fine,iv checked for open cuircuit on inverter,cant fine any bad bits,could this be bad bulbs?how do i test? the inverter board is a inv32s12s,just some help,would a new invertor help?picyure is fine for 3 secs then out.i have a basic cuircuit tester and a capacitance tester,no esr though.iv tried heating the psu caps with hairdrier to see if helped but still same,but im getting good 24v to inverter,the transformers are all clean no burns smell or marks on the underside,can somebody help on how to test these properly?thanks for reading.

[lookimback]

Re: samsung le32r87bd loses backlight after 3 secs

Could you post some good clear pictures of the component side of your board?

Take 3 pics.
Left 3rd of the board.
Middle 3rd of the board.
Right 3rd of the board.

That way we should be able to read the markings on the board.

[charlierfc]

Re: samsung le32r87bd loses backlight after 3 secs

[charlierfc]

Re: samsung le32r87bd loses backlight after 3 secs

hope this helps?thanks for your reply

[charlierfc]

Re: samsung le32r87bd loses backlight after 3 secs

[lookimback]

Re: samsung le32r87bd loses backlight after 3 secs

Ok. For starters, test the fuse. I circled it on the pic. With the power off. Check for continuity through the fuse.

[charlierfc]

Re: samsung le32r87bd loses backlight after 3 secs

Ok. For starters, test the fuse. I circled it on the pic. With the power off. Check for continuity through the fuse.

was 1st thing i done mate,power getting to the transformers,and power going out,can measure whats going to the backlight as its too high for my meter

[charlierfc]

Re: samsung le32r87bd loses backlight after 3 secs

i measured the power out from the 4 bits leading from the transformers when turning tv on,all have power out,but goes too high for my meter to read.so im guessing bulbs?any way at all to test?

[lookimback]

Re: samsung le32r87bd loses backlight after 3 secs

You will probably have to wait until someone with a little more knowledge than me comes along. The pictures are very good which will help a lot.

[tom66]

Re: samsung le32r87bd loses backlight after 3 secs

Check resistance of inverter transformers. With power OFF.

https://www.badcaps.net/forum/attach...1&d=1385298441

Between the two top left outputs, then the two top right outputs, of each transformer. Use 20kohm range. Report reading for each pair of connections.

[charlierfc]

Re: samsung le32r87bd loses backlight after 3 secs

hi tom,the readings i have are
1st transformer L=1.18 R=no reading
2nd L=1.18 R= no reading
3rd L=1.16 r=no reading

am i reading like you asked?
the top 2 on the left the the top 2 opposite on the right of the transformer?
excuse my ignorance!

[charlierfc]

Re: samsung le32r87bd loses backlight after 3 secs

sorry i take it you ment as it faces me!duhh!
ok again!
1st transformer L=1.19 r=1.19
2nd L=1.19 R=1.19
3rd L=1.19 R=1.17
silly me!

[charlierfc]

Re: samsung le32r87bd loses backlight after 3 secs

sorry i take it you ment as it faces me!duhh!
ok again!
1st transformer L=1.19 r=1.19
2nd L=1.19 R=1.19
3rd L=1.19 R=1.17
silly me!

[tom66]

Re: samsung le32r87bd loses backlight after 3 secs

All your transformers seem OK, so most likely you have a bad bulb in the LCD panel.

In the top centre of this picture
https://www.badcaps.net/forum/attach...7&d=1385297274
there is a chip for controlling the backlight, can you read its part #?

[charlierfc]

Re: samsung le32r87bd loses backlight after 3 secs

a99f 745 the 8 legged one?

[charlierfc]

Re: samsung le32r87bd loses backlight after 3 secs

0z9966sn
ma9834.1t
0735b1
is whats written on the larger one with countless legs

[tom66]

Re: samsung le32r87bd loses backlight after 3 secs

OZ9966 is the one of interest. Need a closer pic of it. You can place a solder jumper, which will disable error detect, enabling you to see which bulb in the panel has gone bad.

[charlierfc]

Re: samsung le32r87bd loses backlight after 3 secs

[charlierfc]

Re: samsung le32r87bd loses backlight after 3 secs


sorry for lack of quality,my camera refuses to focus up close,ill try again if you need it,thanks tom

[tom66]

Re: samsung le32r87bd loses backlight after 3 secs

Please check and see if there is continuity between pin #15 of the IC and the end of the capacitor I have marked.