Inspired by Kazar's post about various service menu settings, I took the chance to explore them further on the latest firmware 1280.5.
Many people used to take photos of service menu before making any changes. It's a good practice, but photos are not editable. So I decided to write down most service menu settings in plain text format (see attached "Service Menu.txt"). Yeah, that was tedious and hard work...
Here is a brief excerpt of the most interesting things that I've found. For details, see attached file.
First, let me address the issue with unsuccessful attempts to enter service menu. The point is you have to wait a little after powering off the TV. Press and hold Info button on your remote control, and watch the standby LED. It should be blinking. If not, just wait up to a minute.
Alternatively, connect the power supply to power meter. As soon as power consumption drops below 1 W, the TV is ready to accept the commands to enter service menu.
Option => Factory Reset
Has the same effect as Settings => Support => Self Diagnosis => Reset, but also clears network settings.
Option => MRT Option => Language Set
Defines the languages available in Settings => General => System Manager => Language.
Option => MRT Option => PnP Language
This language is used for onboarding (initial Welcome message) when you power on TV for the first time after purchase, or after reset.
Option => MRT Option => WIFI REGION
In case of any Wi-Fi connectivity problems, change the value to "A".
Option => MRT Option => OTN Support
Seems like this option is not related to software updates via DVB-T/C/S.
Option => MRT Option => OTA Support
Updates the software via wired or wireless connection.
Option => MRT Option => Teletext (TTX)
If set to OFF, teletext is not available, TTX/MX button on remote control doesn't work.
Option => MRT Option => Extended PVR
Allows manual and scheduled recording of TV programmes on external USB device (hard drive or high-performance flash). Also enables Timeshift feature.
Option => MRT Option => HV Flip
Do not change! If set to ON, the picture turns upside down on the next power on.
Option => MRT Option => BT Support
Use to enable Bluetooth after replacing Wi-Fi module with Wi-Fi+Bluetooth module. Not tested yet.
Option => MRT Option => HP LINE
If changed from Headphone to LineOut, allows to get the sound from headphone jack and TV speakers at the same time.
Option => MRT Option => Instant On
If set to ON, TV starts faster, because it skips full initialization, including "Samsung SmartTV" boot logo.
Option => MRT Option => Always Instant On Support
Seems like the purpose of this setting is similar to "Instant On", but for the case when power supply connects to the mains outlet.
Option => MRT Option => Motion plus
If set to OFF, "Auto Motion Plus Settings" menu is replaced with "LED Clear Motion" in Settings => Picture => Expert Settings.
Option => MRT Option => Sound Mirroring
If set to ON, adds "Sound Mirroring" item to Settings => Sound => Expert Settings with the following description: "Share your mobile device's sound using your TV speakers".
Option => MRT Option => SPDIF Support
If set to OFF, "Audio Delay" disappears from Settings => Sound => Expert Settings. It means that Audio Delay is likely to apply to SPDIF out only (not HDMI-ARC, TV speakers, or headphones).
Option => MRT Option => HDR PLUS Support
If set to ON, "HDR+ Mode" item appears in Settings => Picture => Expert Settings, and affects the picture when activated. However, Windows 10 doesn't recognize monitor as HDR.
Option => MRT Option => 360 Audio Support
Probably, relates to VR or Xbox 360 audio.
Option => Production Option => Type Of PANEL KEY
Defines the type and position of OSD (On Screen Display) when using joystick button on the back of TV.
Option => Production Option => Auto Power
Defines whether TV should be turned on/off when the power in outlet is restored after blackout.
Option => Production Option => OCM Support
Do not change! Otherwise, your TV will turn to a brick, constantly showing a picture with TV connected to Samsung One Connect Mini device.
Option => Production Option => Blur Reduction
If set to ON, adds "Blur Reduction" slider to Settings => Picture => Expert Settings => Auto Motion Plus Settings.
Option => Production Option => Smart Audio Support
Replaces "Optimized" item with "Music, Movie, Clear Voice" in Settings => Sound => Sound Mode.
Adds "Auto Volume" to Settings => Sound => Expert Settings.
Option => Production Option => Autovol Support
Enables "Auto Volume" in Settings => Sound => Expert Settings. Go to that menu to activate it.
Option => Production Option => Equalizer Band
Allows to reduce the number of equalizer bands down to 4 in Settings => Sound => Expert Settings => Equalizer.
Option => Production Option => DDP Audio Out Support
Dolby Digital Plus. Not tested.
Option => Production Option => Show power on with mobile
Adds "Power On with Mobile" item to Settings => General => Network. If this item is not activated, power consumption in standby mode is getting down to 0.3 W (from usual 0.5 W), because Wi-Fi and LAN modules are turned off.
Option => Engineer Option => Caption Brightness
Probably, allows to decrease subtitles brightness in movies. Doesn't affect teletext subtitles.
Control => Sub Option => Watchdog
If set to OFF, it may prevent continuous TV reboots.
Control => Sub Option => TTX Group => UserOSD
Defines teletext language. Not related to "Teletext Language Settings" menu in Settings => Broadcasting => Expert Settings.
Control => Sub Option => ACM_MC
If set to ON, adds "Wi-Fi Speaker Surround Setup" to Settings => Sound. Only available when at least one Samsung Multiroom Link compatible speaker is connected to the TV.
Control => Hotel Option => Hospitality Mode
If set to ON, it allows to modify some useful items, but "Broadcasting" section in Settings menu gets unavailable.
Control => Shop Option => Exhibition Mode
If set to ON, disables some buttons on remote control: channel up/down, numbers, off command.
Control => Sound => SPDIF PCM Gain
Changes the volume on SPDIF out when TV is selected as a source.
Debug => No Signal Power OFF
If set to OFF, TV doesn't go to standby mode in 15 minutes after the signal on HDMI input disappears.
Debug => Default HDMI1 Booting
If set to ON, TV switches to HDMI1 after power on. Very helpful when TV is used mostly as PC monitor.
SVC => Info => Panel Display Time
Shows the number of hours the TV was in ON state. The value reverts to 0 after each reset.
SVC => Reset => Apps Reset
Doesn't affect the number of (pre)installed applications in Smart Hub.
SVC => Reset => SVC Reset
Same as Settings => Support => Self Diagnosis => Reset.
SVC => Upgrade => SUBMICOM UPGRADE
Do not change! Many people complain that this setting bricks the TV.
SVC => Other Setting => Expert => N/D ADJ
Night and day adjustment or calibration. When the source is TV, two profiles are added to Settings => Picture => Picture Mode: CAL_Night and CAL_Day.
SVC => Other Setting => Source Banner Hide
If set to ON, prevents annoying banner that appears on the top of the screen after source selection.
WBMovie => MODE
If "Dynamic" is changed to "Movie", items in this section define the default values for Movie picture mode, although not all of them work. These items help to preserve the values in user Settings after entering the service menu.
Picture_2D => SubSetting => Password
Sets the password for entering advanced service menu. Default "0" means "0000".
Settings in this section define the default values for Standard picture mode. These items help to preserve the values in user Settings after entering the service menu.
Every software update resets the values in user Settings menu. Thus, it's a good idea to write them down before updating the software. To make it easier, I've created a table in Microsoft Excel format which includes separate settings for TV and HDMI1/2 sources (see attached "User Settings.xlsx").
There are many ways to control the TV: Infrared, Wi-Fi or LAN, HDMI-CEC. Each one has its own set of codes disclosed on different Internet sites. I've tested some of them, added HDMI-CEC messages, and packed them all into single archive (see attached "Key Codes.zip").
It's worth to note, that I've found HDMI-CEC to be the most reliable way of controlling the TV. For those who interested, see attached "USB-CEC Adapter - Review on Amazon.docx".
Finally, I've collected the extended information about my TV (chips, LCD panel, modules, etc). May be useful for DIY users and repair technicians (see attached "Technical Info.txt").