Samsung LN-S3241D, powers up, has sound, has image, but no backlight

[solderfly]

Hi,
Got this Samsung LN-S3241D.
It had a bad cap on the BN96-03775A board. I replaced that, no change. I then replaced the other caps around it but no change.
I have 24V on the CNM802 connector, 2V on PWM and 5.3V on BL when on.
Where should I look next?

Thanks for your input.

[budm]

Re: Samsung LN-S3241D, powers up, has sound, has image, but no backlight

The power supply is OK (supplying 24VDC for the backlights inverter board), the main board is also supplying the BL_ON, and he PWM Diming signals OK. So the next place o check will be the backlghts inverter board.
Can you please upload goods pictures of the chassis so we can see how all the boards are connected. Then good clear pictures of the inverter board, power supply board.

[solderfly]

Re: Samsung LN-S3241D, powers up, has sound, has image, but no backlight

Here are some of the pictures:

https://lh3.googleusercontent.com/-K...0/S5000593.JPG

https://lh3.googleusercontent.com/--...k/S5000594.JPG

https://lh4.googleusercontent.com/-Y...k/S5000599.JPG

https://lh6.googleusercontent.com/-5...k/S5000600.JPG

https://lh4.googleusercontent.com/-e...k/S5000602.JPG

https://lh4.googleusercontent.com/-D...k/S5000601.JPG

Thanks

[budm]

Re: Samsung LN-S3241D, powers up, has sound, has image, but no backlight

Very common failure on this CMO inverter board is the blown small black fuse F1.

[solderfly]

Re: Samsung LN-S3241D, powers up, has sound, has image, but no backlight

Thank you for the response.
If I see this correctly it is the one with a marking "20" on it.
It does not show open with the ohm meter.
How do I check this the correct way? And could I bridge it?

Thanks again.

[budm]

Re: Samsung LN-S3241D, powers up, has sound, has image, but no backlight

That is the one. What Ohm range do you set on your meter? it should be set to 200 Ohm scale and it should show less than 1 Ohm.
How about other White fuses.
You should see 24VDC on both ends of the fuses.

[solderfly]

Re: Samsung LN-S3241D, powers up, has sound, has image, but no backlight

It is the F1 fuse. I bridged it and now have backlight. TV works.
Thanks you bud.
Now where do I find this fuse, partnumber, or can I just leave it bridged?
Thank you again, great call!

[budm]

Re: Samsung LN-S3241D, powers up, has sound, has image, but no backlight

I use PICO II fuse which is an axial lead fuse, just have to bend the legs to solder it in place or you can get the fuse and soder the wires to the fuse and tape it up.

[solderfly]

Re: Samsung LN-S3241D, powers up, has sound, has image, but no backlight

Thank you.

[dmbarney]

Re: Samsung LN-S3241D, powers up, has sound, has image, but no backlight

It is the F1 fuse. I bridged it and now have backlight. TV works.
Thanks you bud.
Now where do I find this fuse, partnumber, or can I just leave it bridged?
Thank you again, great call!

Can I ask how you bridge the fuse? I have the exact same issue and want to make sure that is case before I buy a new board. Thanks in advance!