Seiki SC-40FK700N with Dim Top Screen...

R

RosemontCrest

Guest
I have a Seiki SC-40FK700N TV with what appears to me to be dim
backlighting along the top 1/3 of the screen. The lower portion of the
screen appears as normal, but about 2 weeks ago the top suddenly went
dim; it\'s still readable, but dim.

I don\'t know how many LED strips this TV has. I would appreciate any
troubleshooting suggestions such as what nominal voltages I should see
where. If it does turn out to be a bad LED strip, should they all be
replaced while I\'m in there?

While I do have plenty of experience dismantling, repairing and
assembling medical devices and computers, I have never worked on a LED
TV. After watching some backlight repair videos, it looks rather
straight forward.

I think that I can find LED strips for ~$15/ea or so, so it may worth
fixing this set. Thanks for any help.
 
On Wed, 16 Nov 2022 17:25:07 -0800, RosemontCrest <bpr@post.com>
wrote:

I have a Seiki SC-40FK700N TV with what appears to me to be dim
backlighting along the top 1/3 of the screen. The lower portion of the
screen appears as normal, but about 2 weeks ago the top suddenly went
dim; it\'s still readable, but dim.

I don\'t know how many LED strips this TV has. I would appreciate any
troubleshooting suggestions such as what nominal voltages I should see
where. If it does turn out to be a bad LED strip, should they all be
replaced while I\'m in there?

While I do have plenty of experience dismantling, repairing and
assembling medical devices and computers, I have never worked on a LED
TV. After watching some backlight repair videos, it looks rather
straight forward.

I think that I can find LED strips for ~$15/ea or so, so it may worth
fixing this set. Thanks for any help.
Click to expand...

Check the voltages on the connector to the backlight, and currents,
if possible. You should eliminate problems there, first.

You\'ll likely only be able to tell if the problem is with wiring
or lamps inside the backplane area after dismantling. You should
be prepared to replace the lamp strips at that time, because the
longer it\'s disassembled, and the more times you repeat that
operation, the more chance of damage in the process.

Most sets won\'t let you see a dead lamp strip - just shutting
down, which is most annoying. A lot of these things would be
capable of running with multiple single led failures in their
strips and no real difference in display quality . . .

.. . . but the designer thinks differently.

A repair can often be made by simply jumpering the defective
led with a suitable voltage dropping resistor or zener, but
this is only something I\'d do if replacement strips
weren\'t on-hand.

I had one set where a dead strip could be mimicked with a
10W power shunt on that line, without opening the thing up.
Dispay was acceptible to the customer, so it went back
with just that addition. Not a real fix and a symptom
that all the lamps needed replacement, but sometimes
quicker is better.

RL
 
On Wednesday, November 16, 2022 at 8:25:11 PM UTC-5, RosemontCrest wrote:
I have a Seiki SC-40FK700N TV with what appears to me to be dim
backlighting along the top 1/3 of the screen. The lower portion of the
screen appears as normal, but about 2 weeks ago the top suddenly went
dim; it\'s still readable, but dim.

I don\'t know how many LED strips this TV has. I would appreciate any
troubleshooting suggestions such as what nominal voltages I should see
where. If it does turn out to be a bad LED strip, should they all be
replaced while I\'m in there?

While I do have plenty of experience dismantling, repairing and
assembling medical devices and computers, I have never worked on a LED
TV. After watching some backlight repair videos, it looks rather
straight forward.

I think that I can find LED strips for ~$15/ea or so, so it may worth
fixing this set. Thanks for any help.
Click to expand...

Replace them all if you think a 40\" TV is worth the effort. Don\'t buy used strips, buy new ones. Check Shopjimmy.
Guaranteed to be an LED issue.
 
On 11/18/2022 5:23 AM, legg wrote:
On Wed, 16 Nov 2022 17:25:07 -0800, RosemontCrest <bpr@post.com
wrote:

I have a Seiki SC-40FK700N TV with what appears to me to be dim
backlighting along the top 1/3 of the screen. The lower portion of the
screen appears as normal, but about 2 weeks ago the top suddenly went
dim; it\'s still readable, but dim.

I don\'t know how many LED strips this TV has. I would appreciate any
troubleshooting suggestions such as what nominal voltages I should see
where. If it does turn out to be a bad LED strip, should they all be
replaced while I\'m in there?

While I do have plenty of experience dismantling, repairing and
assembling medical devices and computers, I have never worked on a LED
TV. After watching some backlight repair videos, it looks rather
straight forward.

I think that I can find LED strips for ~$15/ea or so, so it may worth
fixing this set. Thanks for any help.

Check the voltages on the connector to the backlight, and currents,
if possible. You should eliminate problems there, first.

You\'ll likely only be able to tell if the problem is with wiring
or lamps inside the backplane area after dismantling. You should
be prepared to replace the lamp strips at that time, because the
longer it\'s disassembled, and the more times you repeat that
operation, the more chance of damage in the process.

Most sets won\'t let you see a dead lamp strip - just shutting
down, which is most annoying. A lot of these things would be
capable of running with multiple single led failures in their
strips and no real difference in display quality . . .

. . . but the designer thinks differently.

A repair can often be made by simply jumpering the defective
led with a suitable voltage dropping resistor or zener, but
this is only something I\'d do if replacement strips
weren\'t on-hand.

I had one set where a dead strip could be mimicked with a
10W power shunt on that line, without opening the thing up.
Dispay was acceptible to the customer, so it went back
with just that addition. Not a real fix and a symptom
that all the lamps needed replacement, but sometimes
quicker is better.

RL
Click to expand...

Thanks for the useful tips, legg. It may be a few more days until I look
into it.
 
On 11/18/2022 1:23 PM, ohg...@gmail.com wrote:
On Wednesday, November 16, 2022 at 8:25:11 PM UTC-5, RosemontCrest wrote:
I have a Seiki SC-40FK700N TV with what appears to me to be dim
backlighting along the top 1/3 of the screen. The lower portion of the
screen appears as normal, but about 2 weeks ago the top suddenly went
dim; it\'s still readable, but dim.

I don\'t know how many LED strips this TV has. I would appreciate any
troubleshooting suggestions such as what nominal voltages I should see
where. If it does turn out to be a bad LED strip, should they all be
replaced while I\'m in there?

While I do have plenty of experience dismantling, repairing and
assembling medical devices and computers, I have never worked on a LED
TV. After watching some backlight repair videos, it looks rather
straight forward.

I think that I can find LED strips for ~$15/ea or so, so it may worth
fixing this set. Thanks for any help.


Replace them all if you think a 40\" TV is worth the effort. Don\'t buy used strips, buy new ones. Check Shopjimmy.
Guaranteed to be an LED issue.
Click to expand...

Thank you. Would you mind elaborating about the supposed worth of a 40\"
TV? Would a smaller or larger TV be more suitable for the room it is
intended? I am sincerely curious.
 
On Saturday, November 26, 2022 at 7:54:51 PM UTC-5, Beeper wrote:


Replace them all if you think a 40\" TV is worth the effort. Don\'t buy used strips, buy new ones. Check Shopjimmy.
Guaranteed to be an LED issue.
Thank you. Would you mind elaborating about the supposed worth of a 40\"
TV? Would a smaller or larger TV be more suitable for the room it is
intended? I am sincerely curious.
Click to expand...

Speaking from a repairer\'s standpoint, you need to price the job out the door for a max of 1/2 the replacement cost of the product. If the TV is yours, then your labor is free (something that it is NOT for a professional) and worth the repair if you 1) like the TV and 2) don\'t break the screen or damage the bonding in the process.

As for screen size, that is up to the end user.
 
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