NEC LCD1860NX - Problem when left off for some time

[bonkers]

Hi,
My workplace chucked out a NEC LCD1860NX I took it home and plugged it into my desktop and it came on straight away everything seemed fine.

I used the computer for several hours with no problems. I then turned the monitor off with the power button and had my dinner, Then some time later pressed the power switch and the green LED came on and could see the backlight flash on/off but no desktop.

Now if i unplug the d-sub cable and press the power and the exit button it will display a no signal dialogue box (sometimes takes a few goes) Then if the d-sub cable is reconnected the desktop is back and will work for as long as i want.

Now this happens every time turn off and leave for some time,

Bye the way once working if i turn off and on within a few minutes it comes back on no problem.

Also if I use computer power settings to let the monitor sleep same problem, comes out of sleep mode, green LED on, black (blank) screen not even the settings panel will display

This is so annoying as when it is on its perfect any help or ideas to try would be much appreciated.

bonkers

[shovenose]

Re: NEC LCD1860NX - Problem when left off for some time

hmm, i have no clue

but do check for bad caps inside. look for any that are bulging the tops or leaking brownish crud. also report on brand of capacitors used.

[retiredcaps]

Re: NEC LCD1860NX - Problem when left off for some time

What you are describing sounds like bad caps inside. As caps age, they dry up, and/or lose uF, and/or have high ESR. If I understand this correctly, as the monitor warms up, the ESR (ohms) of the caps drops. This allows the monitor to operate.

As shovenose suggested, open up the monitor and look for bad caps.

If you do see bad caps, replace them all with low ESR caps with something from the following list ...

https://www.badcaps.net/forum/showthread.php?t=2280

[bonkers]

Re: NEC LCD1860NX - Problem when left off for some time

Thank you for your quick response.

I have opened up the monitor and it does indeed have have some bad caps, three on the power board.

This webpage http://pkrobot.freehostia.com/LCDRepair8.htm shows 2 of the defective caps the other i have is the smaller one next to the aluminum block with fins on.

I should of mentioned that even though i have repaired many computers + laptops including screen replacements, I have never repaired a monitor, also i have never soldered anything in my life so i am probly best to get someone else to do this for me.

Thankyou for giving me the confidance to open it up though as monitors have always scared me a little with there CAUTION to prevent electric shock do not remove enclosure No user serviceable parts inside warnings.

[retiredcaps]

Re: NEC LCD1860NX - Problem when left off for some time

also i have never soldered anything in my life so i am probly best to get someone else to do this for me.

Good soldering video by Curious Inventor

http://www.youtube.com/watch?v=I_NU2ruzyc4

[bonkers]

Re: NEC LCD1860NX - Problem when left off for some time

Thanks,
I will get back to you when i feel confidant enough to tackle this and have sourced the right components and a suitable soldering iron so i can do this safely.