I have a un55c9000zfxza it powers up the screen glows but remains dark, I've got sound, controls seem to work, but no menu OSD

if the power lamp is dead, then there is no power.
if the lamp glows, there is.
if it glows try the OSD menu, hit the monitor keys, got OSD?
no OSD is bad monitor.
good OSD?
yes !
try windoz safe mode F8, dead?
dead still?
bad monitor.

OSD LOCKED/UNLOCKED
This function allows you to lock the current control settings, so that they cannot be inadvertently changed. Press and hold the MENU button for several seconds. The message "OSD LOCKED" should appear. You can unlock the OSD controls at any time by pushing the MENU button for several seconds. The message "OSD UNLOCKED" should appear.

Maybe the problem is in the power supply board.Ethier the capacitor or the regulator transistor.The trnsistor can know that is deffective by using digital tester not for looking the apperance and also the capacitor.So its better to check by the authorized technician.

*NOTE* This answer was actually found on another source.
The easiest solution to try is to reset the on screen display in the menu. Hold down the Menu button (it is probably marked Ok) for at least a minute. A menu list will appear on your monitor screen. Using the adjust button, press the arrows to enter the menu. Scroll down to the Reset section. On the right side of your screen, you will see an alternating Yes/No choice. When the Yes message flashes, press the Ok button. The menu should be reset and the flashing OSD control message should disappear.

If resetting the OSD doesn't work, then you probably have a physical problem with your Menu button. Sometimes, particularly on older machines, the connections to the circuit board are dirty or failing. Because you have to actually get into the monitor itself, you will probably void any remaining warranty by attempting this fix. If your monitor is still under warranty, contact the manufacturer to see if there is a local repair shop that can help you.

If you want to tackle this issue yourself, grab a screwdriver and take the plunge. Remove the casing on the monitor itself and locate the contact switch for the menu button on the circuit board. Sometimes, just working it with your fingers or a screwdriver is enough to unstick it - you can try to clean off any dust or grime that has accumulated around it to see if that is the cause.

Hello,
In order to resolve the OSD menu locked error:
1. You must reset the on screen display in the menu.
2. Hold down the Menu button for at least 60 seconds.
3. A menu list will appear on your monitor screen.
4. Using the adjust button, press the arrows to enter the menu.
5. Scroll down to the Reset section.
6. On the right side of your screen, you will see an alternating Yes/No choice.
7. When the Yes message flashes, press the Ok button.
8. The menu should be reset and the flashing OSD control message should disappear.

23 Oct 2008 ... There are a few things you can do to solve the problem, ... The menu should be reset and the flashing OSD control message should disappear. ... controls locked, then it comes up again saying OSD main controls unlocked. ... I have a Philips 190S monitor. I do have a button to enter the onscreen menu. ...
filetonic.com/blog/2008/10/23/osd-main-controls-blocked/

monitor shows osd lock how to solve this problem

no country stated or if not usa what is your line power?(volts AC)
your PSU is inside monitor not outside, so uses a simple line power cord. (just wires)
12 year old monitors, found, (dead)
page one of your user guide is clear, read it yet?
seems not.,
Auto-ranging, 90 to 265 VAC
1280 x 1024 @ 60 Hz, 75 Hz (never higher) resolution settings.
those are very old monitors.. worth like $10 used.
if the power lamp shows wrong, the monitor is dead.
right button is power to the right of it is a power led that must glow.
the old monitors had CCFL backlamps before year 2010.
those are back lamps, that fail fast. 20k hours, fast. (short)
first is the power switch
2nd is a working PC with at least sync signals on 2 pins
Horz/vertical.
then the OSD screens work of not the monitor IS DEAD.
inside this OLD monitor is sleep time, turn if off with OSD menu's its nothing but trouble.
some have an OSD lock, so hold the menu key for 10 seconds
and it unlocks. button 2 from left is MENU.
see page 4-10
the guide is here. not too good , poor diagnosis sections
http://h10032.www1.hp.com/ctg/Manual/c00276671



specs.
https://support.hp.com/us-en/product/hp-l1940-lcd-flat-panel-monitor/427303/document/c00278650#AbT3


testing
power it on, LED power , glows.
with a PC working, say running any BIOS screen only....
or running, windows, in low resolution mode 1280 x 1024
if wise set the pc up to that first. not second.
then plug in the vga cable so the MOnitor only sees that signal above. (if you do above wrong, monitor shows OUT OF RANGE on the screen)

at mon.
PUSH the OSD button, menu, if OSD is dead the montor is dead.
OSD= on screen display., (yes the LDC has brain inside)
then take a flash light . point it at screen
see data now, if yes, in the beam is data the back lamp is dead
as are most 12 years old montors now.

see those 4 cream colored connectors bottom of this PCB
those are the high voltage CCFL lamps.
2 lamps 4 ends. the lamps are bad or the board 500 to 1000vdc
power supply is dead.

reset your monitor settings with deafaults with menu.u see some buton on lcd or monitor.

Does the lcd screen have a glow to it ? Or is it really dim if u get real close to screen u can see images moving ?
it it has a glow to it you panel lighting is fine but you control board is bad. If you have a dark screen and see faint images you panel back lighting is out u can check the power with a meter at the connection to inverter board on panel.