Samsung LED TV Model LN-S4041D intermittent loss of picture (sounds still works)

[Wnowickiz]

I read a lot about bad caps on these TVS, but could a intermittent loss of picture be caused by caps? I will turn it on and sometimes it works fine, shut it off and turn it on later with no picture. No other symptoms like cracking or popping.

Before, I tear into it and look for swelling caps, can caps fail like this?

Thanks in advance,

Bill

[tom66]

Re: Samsung LED TV Model LN-S4041D intermittent loss of picture (sounds still works)

Capacitors would not be a typical suspect with this problem. In a dark room, when the picture is gone, can you see a glow from the screen or not? (Backlight)

[Wnowickiz]

Re: Samsung LED TV Model LN-S4041D intermittent loss of picture (sounds still works)

I will check thanks. I am pretty sure it does not have a glow, but what would be if there isn't one?

Thanks again.

[tom66]

Re: Samsung LED TV Model LN-S4041D intermittent loss of picture (sounds still works)

T-con or main board w/ glowing screen.
Inverter, power or main board w/o glowing screen.

[Wnowickiz]

Re: Samsung LED TV Model LN-S4041D intermittent loss of picture (sounds still works)

I made need a scope to check those things...

[tom66]

Re: Samsung LED TV Model LN-S4041D intermittent loss of picture (sounds still works)

You usually won't for most LCD TVs, but it can help to have one.

[Wnowickiz]

Re: Samsung LED TV Model LN-S4041D intermittent loss of picture (sounds still works)

The tv is working great tonight. Go figure.

[Wnowickiz]

Re: Samsung LED TV Model LN-S4041D intermittent loss of picture (sounds still works)

I tried the TV this morning and the screen is blank, no backlight and sound is working. Now what?

[tom66]

Re: Samsung LED TV Model LN-S4041D intermittent loss of picture (sounds still works)

Take the cover off, and provide clear pictures of each of the boards in the TV.

[Wnowickiz]

Re: Samsung LED TV Model LN-S4041D intermittent loss of picture (sounds still works)

Ok, will do.

[Wnowickiz]

Re: Samsung LED TV Model LN-S4041D intermittent loss of picture (sounds still works)

Here you go. I do not see bulging caps anywhere.

[Wnowickiz]

Re: Samsung LED TV Model LN-S4041D intermittent loss of picture (sounds still works)

Second pic.

[kc8adu]

Re: Samsung LED TV Model LN-S4041D intermittent loss of picture (sounds still works)

replace all secondary caps and resolder everything attached to a heatsink on that power supply.
that is not an led set either.
i see these often.

[Wnowickiz]

Re: Samsung LED TV Model LN-S4041D intermittent loss of picture (sounds still works)

Ok, thanks. All the can style caps or the others also? Should take any readings prior?

[Wnowickiz]

Re: Samsung LED TV Model LN-S4041D intermittent loss of picture (sounds still works)

I tested all the diodes and transistors in circuit. DB851 and db803 appear bad (both directions). Could those be the cause? I am looking for a schematic for the BN44-00134D. Thanks again.

[tom66]

Re: Samsung LED TV Model LN-S4041D intermittent loss of picture (sounds still works)

Intermittent would be unlikely to be caused by a permanent failure.
Schematic of PSU if it's any help:

[Wnowickiz]

Re: Samsung LED TV Model LN-S4041D intermittent loss of picture (sounds still works)

You were correct tom66. The replacement diode did not fix anything. Should I test the voltages prior to changing out. All the caps? Thanks again.

[tom66]

Re: Samsung LED TV Model LN-S4041D intermittent loss of picture (sounds still works)

Yes, check all the voltages on the output side, in particular check the backlight on/off signal CN1803 pin 1.

[Wnowickiz]

Re: Samsung LED TV Model LN-S4041D intermittent loss of picture (sounds still works)

Thanks.