Backlights came in but before putting them, did more investigation and found its the stupid SONY's built-in YouTube app.
The menu system looks plenty bright. My Firestick 4K Max over the ARC HDMI port will enable choosing HDR Video or HDR Vivid in picture mode. HDR Vivid is super bright. The problem is the built-in Youtube app (running latest firmware 4.931 link). This TV doesn't really have very much of an App Store. Just Prime Video, Youtube and couple of others. I'm guessing Youtube video implementation is outdated and somehow doesn't match their own TV's HDR brightness settings....
howardc64
Badcaps Veteran
Last Activity: 03-02-2026, 10:26 PM
Joined: 06-03-2017
Location: Seattle WA
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Yeah make sense, its too dim anyways so going to replace the backlight and give this TV a few more good years.
Son was 2nd in Pokemon cards world championship a few years back. Pikachu holding the silver cup is the 2nd place prize haha.
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Got one of these (KD60X690E) and had 6 blinking red error. Tested backlight and it shows on with close to 150v (10 bars x 5 LED x 3V/LED) Did reset sequence and backlight/TV turned on and no more 6 blinking red led code. Has been working fine for a few hours. But backlight is not super bright (even set to max of 50) and seems dim in a brightly lit room (YouTube white screen video shows no burnt out LEDs)
Does anyone know if these backlight will lose brightness as they age? I did read they turn blue with age (like the LGs I've seen) although this one has not. Regular and service menu...Last edited by howardc64; 01-24-2026, 01:45 PM.Leave a comment:
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Fixed backlight but unfortunately broke the LCD in upper corner while removing the outer frame
Only put slight pressure on the LCD to pop free the frame and it cracked. Probably due to rigid metal outer frame (most are plastic) Lesson for future is pop the corners free with pry tool from underneath.
Anyway, backlight had a short that only occurs when turned on. The LED strip is screwed on to the chassis so if any LED has a short from + to LED bar, then its a short to PSU ground.
...Last edited by howardc64; 01-19-2026, 02:45 PM.Leave a comment:
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More definitive test
Disconnect LED connector from PSU (PSU is not involved in the test)
VOM diode mode - probe to chassis, + probe to 2+
LED tester + probe to 2+, tester - probe to 2- light up #2 LED circuit, whenever tester - probe is removed from 2-, there is a brief beep on VOM
So 2+ has a short to chassis whenever #2 LED circuit transitions from lit to not lit....Leave a comment:
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ok I think I proved LED strip is shorting to chassis only when turning on
All boards and connectors plugged in. VOM in diode mode. - probe on chassis, + on either 1+ or 2+ of LED connector. Plug in TV, backlight flicker occurs and periodic beep.
Will order LED strip....Leave a comment:
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Yes I did this test. Unplugged the connector and checked 1+ 1- 2+ 2- to chassis. All are OL. Also check 4 connections against each other, all OL...Leave a comment:
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Here are the measurements taken on CNL802 (LED backlight connector on PSU)
unplugged : 1+ 1- 2+ 2- to each other and to chassis all OL
plugged results
https://docs.google.com/spreadsheets...it?usp=sharing- 2+ 1- shorted is also observed on my known good Samsung UN55KU PSU so must be the correct design although I don't understand it.
- Some resistance values continuously increase and decrease. I guess measuring a charging cap?
- Some resisteance value are different if red/black OHM meter probe reversed. I guess
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Got a UN49MU7000FXZA failure : maybe PSU or LED
Plug in AC without using remote to power on. One side (left side looking from front of TV) backlight flashes repeatedly and no standby light. Here is video : TV is upside down.
https://youtu.be/VFtIoiuqdgA?si=-yT9qLqFSResXhe-
1. Disconnect only backlight from PSU and plug into AC, standby light on, turn on TV with remote see full Samsung menu with flashlight
2. Disconnect pin 4 (+ on LED strip on the flashing side) on LED connector from PSU result in same as 1 (see last pic)
3. Disconnect only main...Last edited by howardc64; 01-02-2026, 12:38 AM.Leave a comment:
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UN65NU7100FXZA Backlight Replacement Notes
Edge lit LED bar failed. Replaced and here are some notes for future repair efforts
These LED bars have 4 serial circuits. The series that failed (about 1/2 of LEDs failed) is also where the diffuser plexiglass had slight melting. Don't know if the melting that caused the failure or remaining surviving LEDs ran hotter.
Typical eBay/Aliexpress LED bar slightly different than OEM
one end of the alignment marks don't line up for a prefect fit. Will need to cut a tab on one end of the chassis. I cut the 2 chassis tabs in the center of the TV....Last edited by howardc64; 12-18-2025, 08:59 PM. -
oh ok I understand now. Good idea. I closed the TV now waiting for replacement edge LED bar. Will try to desolder the jumpers when I open it again and post results....Leave a comment:
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Thanks, I think jumpers are too big and will spread out the connector clasps. Need to find thinner blades.
I'll just gamble on bad LEDs on these 2 TVs and probably just salvage a connector out of a PSU for future....Leave a comment:
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Got another 2 Samsung edge lit TVs with these connectors. Really like to test the LEDs without PSU before full disassembly (in case failure is PSU). Anyone know if safe to run LED tester with the PSU connected to the LED connector? Everyone showing how to use LED tester don't show this particular connector and its challenges.
Note its not possible to access the LED connector with PSU removed. Can jam the LED test probes in which will widen the connector clasps and no longer make contact to PSU connector. No access from the back of the connector (LED test probe handle too wide to enter...Last edited by howardc64; 12-16-2025, 03:30 PM.Leave a comment:
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HP Envy Photo 7858 dead
Completely dead when pluged in (No lights, no LCD display, no voltage on USB port, nothing moves) Fixed a similar model ( Nearly identical chassic layout and logic board HP Officejet 5740 ) with boot problems due to failed electrolytic cap in the power section ( link ) Unfortunately a different failure behavior on this one.
Logic Board Short near power section
Power rails are shorted ( D11, D270, C250 etc ) D11 + C250 removal didn't remove the short. FLIR video shows its the TI SOC ( U200 = TI SNB7031 custom chip, no data sheet ) gets hot first. My hotair skills probably...Last edited by howardc64; 12-14-2025, 06:27 PM. -
One more note, the left (looking at TV from front) stand mounting bracket has 2 possible positions. Wrong one won't have the indent for the upper stand mounting bolt and will break it. So careful with this on reassembly. I made this mistake.
On the cut reflector paper to extract bottom row of LED strip. The original paper is lifted slightly above the chassis as its glued to the LED strip. When this is cut, there will be a gap (even if the paper is taped down against the tub) and likely cause uneven brightness at the bottom of the screen. Don't know how to avoid this without separating...Last edited by howardc64; 12-03-2025, 04:02 PM.Leave a comment:
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Finally got around to replacing the backlights which is PITA on this model.
- There are 16 strips, 8 rows on each side
- Bottom row is glued to the reflector paper. Need to cut the paper to remove which leaves paper very loose to the frame. Probably best to double side tape down the loose paper (I didn't do)
- Top 4 rows have 2x screw on LED bar besides glued down bar.
- Replacement strips comes in 32 pieces and 2x join together to match 1 OEM strip. This allows shorter package shipping. Need to cut the reflector paper where the joint is to keep reflector paper flat.
- Due to cutting the relfector
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Just fixed a 2011 27" LiteON PSU with this idential failure.
T6.3A fuse blown
Both MOSFETs shorted
1x 10 ohm SMD resistor open
Replaced and iMac booted
...
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Looks like have one with bad backlight. Here is a diagnostic summary. Will post update after backlight order/replacement and see how easy to get sticky reflector paper off.
Model
Right side backlight failure
This is a white screen test from youtube
LED tester results
Looks like 4x serial circuit. Each circuit is 6 6V LEDs/row x 4 rows or 130V @ 5.4V/LED. A pair of serial circuit is connected in parallel so if only 1 serial circuit fails in this parallel pair causing PSU to safety protection shut off the rail,...Leave a comment:
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Does main have SPDIF light? when thats on, it usually means main mostly booted okay. Also does main make UI sounds? If so then smarttv OS is running.
I guess check t-con inductors for voltage rails to see if they make sense.Leave a comment:
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Tried disconnecting left and right panel flex one at a time to see if either 1/2 of the panel has the error? On most Samsungs, require jumper FB_TRDY_1 pin.
https://www.badcaps.net/forum/troubl...el#post3686471Leave a comment:
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