1second to black HPf2105 monitor LTM210M2-L01 screen

[bertv2]

I am a total amateur trying to fix an HPf2105 monitor. It sounds like the "2 seconds to black" problem with variations. The problem did not slowly develop but happened all at once. The backlight lasts for about 1/2 second to 1 second and then goes black. The bluelight stays on. The button itself seems to work ok. With a flashlight I can barely see data on the screen. I first bought a 4H.L1S04.A10 inverter board on ebay which was supposed to have been tested and guaranteed and swapped it for mine. No change, so I sent it back. (The caps on my inverter board look fine but have not been tested.) Because some people had luck changing out the button board I bought a 4H.L1S03.A10 button board on ebay which was supposed to have been tested and guaranteed and swapped it for mine. No change, so I sent it back. Thinking I had it narrowed down to the screen, and not wishing to tear down the screen to check the ccfls, I bought a LTM210M2-L01 screen on ebay which was supposed to have been tested and guaranteed and swapped it for mine. No change, so I sent it back. The caps on the other boards look fine. Do I throw up my hands? If not what is my next step? I have a vacuum tube voltmeter and a very rudimentary multitester from Harbor Freight. I can solder, but am without diagnostic experience. Help.

[sabre504]

Re: 1second to black HPf2105 monitor LTM210M2-L01 screen

Usual problems with these are faulty transformers on the inverter board and or bad solder joint on the top set of lamps on the screen .

I would start by testing the transformers on the board and would be well worth reading Retiredcaps 2 sec to black test write up

[budm]

Re: 1second to black HPf2105 monitor LTM210M2-L01 screen

Common failure in this model is bad lamp wiring, fixed about dozen of these, all with bad wires on the lamp.
http://s807.photobucket.com/user/bud...33364513485279
Good to check all the voltages and transformer resistance on the secondary side also.

[bertv2]

Re: 1second to black HPf2105 monitor LTM210M2-L01 screen

Thanks, Sabre and Budm. Wouldn't the problems you suggest have disappeared when I changed out the inverter board and the screen?

Could I have gotten another bad inverter board or screen when I changed them out?
Assuming the replacement inverter board and replacement screen I tried were good. What else can I try? As I've said, I've swapped the inverter board, the button board, and the screen, all without solving the problem. It it is none of them, what could it be?

Thanks for your help. I'm against the wall on this one.

[selldoor]

Re: 1second to black HPf2105 monitor LTM210M2-L01 screen

OK - so if you can see a faint picture on screen the problem is with the inverter or the lamps or the voltage to the inverter.

Welcome to the forum-
We can help a lot more if you please post good clear pictures of the whole chassis, and then pictures of each board, front and back (in the same orientation) and close up of connectors, (max resolution 2000x2000 and 2MB) using the manage attachments button, which is found by clicking "go advanced" under quick reply.

Please do not post inline and offsite as they slow down the loading of pages.

Examples of what is needed

https://www.badcaps.net/forum/attach...7&d=1280167246

https://www.badcaps.net/forum/attach...6&d=1280167246

https://www.badcaps.net/forum/attach...4&d=1280167246

[bertv2]

Re: 1second to black HPf2105 monitor LTM210M2-L01 screen

You mention that the usual problems are with the inverter board or the ccfls. I have swapped both of these without improvement to the situation. Your third alternative was "voltage to the inverter board".

Could this be the case even though the screen looks normal for the first half second to one second or so?

I wish I were set up to take pictures of the entire chassis but at this stage I am not. Does the main board supply voltage to the inverter board?

What about swapping out the main board to see if that solves the problem.

I repeat, I have already swapped out the inverter board and the screen, one at a time, with no improvement. Also the button board was swapped out with no improvement. What else can I swap out that could be the culprit?

Thanks for the welcome and your time and good advice.

[sabre504]

Re: 1second to black HPf2105 monitor LTM210M2-L01 screen

Chrck the voltages that run from the psu to the inverter board and report findings .

As you say you can see the screen working it is unlikely to be the main board .

I have one of these in my shed with a damaged screen i will dig it out to check what they should be