FAQ
TL;DR: Samsung UE40ES6900 main-board faults are common; this model shipped with 2 panel variants and “You can insert any disc between 6500–6900.” [Elektroda, baki, post #16899876]
Why it matters: This FAQ helps DIY repairers quickly confirm a bad main board and pick a working replacement with the correct panel code.
- Supported 40" panels for UE40ES6900: LTJ400HV09‑V and LTJ400HV09‑N. [Elektroda, baki, post #16899876]
- Donor main boards: ES6500–ES6900 family; set the correct Panel Type after swap. [Elektroda, baki, post #16899876]
- Service Menu entry from standby: Info → Menu → Mute → Power; some options require a service remote. [Elektroda, baki, post #16899876]
- For panel LTJ400HV09‑B, set Panel Type to 40A1AF6E. [Elektroda, baki, post #16935883]
- Board-level repair option: reprogram/replace eMMC; confirmed working after soldering. [Elektroda, Indyczes, post #16896572]
Quick Facts
- Supported 40" panels for UE40ES6900: LTJ400HV09‑V and LTJ400HV09‑N. [Elektroda, baki, post #16899876]
- Donor main boards: ES6500–ES6900 family; set the correct Panel Type after swap. [Elektroda, baki, post #16899876]
- Service Menu entry from standby: Info → Menu → Mute → Power; some options require a service remote. [Elektroda, baki, post #16899876]
- For panel LTJ400HV09‑B, set Panel Type to 40A1AF6E. [Elektroda, baki, post #16935883]
- Board-level repair option: reprogram/replace eMMC; confirmed working after soldering. [Elektroda, Indyczes, post #16896572]
How do I diagnose the 5‑blink boot loop on a UE40ES6900?
Disconnect the LVDS between main board and T‑Con and power on. If it still cycles, the main board is bad. Also check the tiny fuse near the PSU connector on the main board; if open, the memories lose power and the set won’t boot. “Disconnect the lvds cable… If so, the main board is damaged.” [Elektroda, baki, post #16888362]
How can I confirm it’s not the power supply?
If the backlight turns on with the main board unplugged, the PSU and LED driver rails are likely fine. Measured A5V, B5V, B13V, and Vamp matching the PSU label also supports a healthy PSU. Persistent cycling with LVDS removed points back to the main board. [Elektroda, stasimon1981, post #16887926]
Which replacement main boards are compatible?
Use a donor main board from the ES6500–ES6900 series. After installation, enter Service Menu and set the Panel Type to match your LCD. This cross‑series swap works when the panel type is correctly configured. “You can insert any disc between 6500–6900.” [Elektroda, baki, post #16899876]
Can I use a board from a different screen size, like 55"?
Yes. A UE55ES6800 main board booted a UE40ES6900 once the Panel Type was changed in Service Menu. You must match the panel code for correct image and features. Connect HDMI/antenna after confirming on‑screen operation. [Elektroda, stasimon1981, post #16935457]
What Panel Type should I set for LTJ400HV09‑B?
Set Panel Type to 40A1AF6E. This mapping produced correct operation in the thread. If multiple 40‑inch options appear, choose 40A1AF6E for the LTJ400HV09‑B sticker. [Elektroda, baki, post #16935883]
How do I enter Samsung Service Menu and change Panel Type?
With TV in standby: 1) Press Info, 2) Menu, 3) Mute, 4) Power. Navigate to Option → Panel Type and select the correct code. Some sets need a service remote to enable changes. Exit and power cycle to save. [Elektroda, baki, post #16899876]
What panels did the UE40ES6900 originally ship with?
Two 40-inch panels are listed: LTJ400HV09‑V and LTJ400HV09‑N. When using donor boards, you may need to change Panel Type accordingly. Using the wrong type can affect features like 3D. [Elektroda, baki, post #16899876]
What are LVDS and T‑Con in this context?
LVDS is the high‑speed link from the main board to the T‑Con (timing controller), which drives the LCD panel. Pulling the LVDS checks whether the main board is causing the boot loop; if the loop continues, the main board is suspect. [Elektroda, baki, post #16888362]
Is repairing the original main board worth it?
Yes. A common failure is boot media (eMMC) corruption. Replacing or reprogramming the eMMC with a known image restored normal start after soldering on this chassis. “After soldering the TV started without problems.” [Elektroda, Indyczes, post #16896572]
How do I tell if a donor board’s panel connector will fit?
Check the panel ribbon connector style. For this chassis, a metal tape‑in socket on the donor board matches the logic ribbon used by the LTJ400 series. Match connector type before buying. [Elektroda, elmo071, post #16896286]
Will 3D still work after a board swap?
Picture typically works once Panel Type matches, but 3D may fail if the donor board expects a different 3D configuration. If 3D matters, choose a donor with the same 3D profile. [Elektroda, baki, post #16899876]
What does the small fuse near the PSU connector do?
That miniature fuse feeds the memories on the main board. If it opens, the system firmware cannot power up and the TV will cycle. Check and replace only with the same rating. [Elektroda, baki, post #16888362]
Is there an official compatibility list for these boards?
No universal list exists. Use ES6500–ES6900 donor boards, verify the panel ribbon connector, and set Panel Type in Service Menu. This method is repeatedly validated in the thread. [Elektroda, elmo071, post #16896286]
Which panel code is better: 40R1AF6E or 40A1AF6E?
For LTJ400HV09‑B, use 40A1AF6E. 40R1AF6E appears in menus but does not match the LTJ400HV09‑B mapping provided by contributors. Choose 40A1AF6E to avoid image issues. [Elektroda, baki, post #16935883]
What simple 3‑step check should I run before buying parts?
- Unplug LVDS and power on. 2. Inspect/measure the small fuse on the main board. 3. Confirm backlight and PSU rails operate with the main board disconnected. Replace or repair the main board if the loop persists. [Elektroda, baki, post #16888362]
I measured the voltage on the power board but the motherboard is too much for me. 