Problems with a NEC Multisync CRT

[linuxlove]

Long time, no [strike]POST[/strike] post. (edit: no strikethrough bbcode? )

Basically, I got an old NEC Multisync 3V CRT and it doesn't work. When you try turning it on, the thing starts clicking repeatedly and never stops until you cut the power. Nothing shows up on screen; I don't think the monitor warms up in time to display anything.

Here's a video where you can hear the clicking: http://www.youtube.com/watch?v=pZVnOE8jxXU

Any ideas, and perhaps more importantly, is it even worth saving?

 

[Stone]

If you need a replacement I've got the NEC MultiSync original model JC-1401P3A and it works perfectly. I've also got its Forefront clone model MTS-9600 which just might be a even a bit better. They both work with Monochrome, CGA, EGA and VGA adapters.

 

[Old Thrashbarg]

That clicking is a relay... probably the one that controls the power-save mode. The question is, what's causing it to cycle like that. I'd start by checking out the power supply section, but it could be a number of other things too.

I believe this is be the service manual for it, so having that should help quite a bit.

 

[linuxlove]

I think I might have just broken it further. This monitor is old enough where the majority of picture controls is still controlled by potentiometers. It already doesn't work, so fiddling around with the controls while the thing is on can't hurt, right?

Wrong.

The clicking is still there, but it's much more faint now, only slightly louder than the second hand on an analog wristwatch. I think whatever was causing the audible clicking failed completely. Perhaps it's a transformer that's making this very faint click? The power indicator LED would also come on when the audible clicking was going on, but not anymore.

Old Thrashbarg: Thanks for the manual, I'll have a look through it.

 

[barythrin]

I didn't quickly find the same symptom and I bet you found this site already but this is sort of a faq on crt repair. Be careful poking around of course.. you're aware of the flyback transformer right?

 

[linuxlove]

Be careful poking around of course.. you're aware of the flyback transformer right?

The dangers of the flyback transformer is one of the things that's stayed vivid in my memory ever since I first read the A+ Certification, Second Edition manual.

With regards to that FAQ, glancing through the repair section I saw the part about the vacuum being broken in the tube. As far as I can tell, the tube itself is perfectly fine; I saw no flashes inside the tube back when it was audibly clicking. Perhaps I'll be brave enough to pull the tube and boards fully out of the case in a day or two :D

 

[orion3311]

It sounds to me like you're getting a picture, if so, its possible the clicking you hear is the flyback arcing out. Either it cracked open from age or its also possible it sat in a damp basement for too long. Sometimes you can rescue the fly back filling in the crack with RTV but that doesn't always last. Might be able to find an oem fly out there too.

If you get no picture and the power led kinda pulses a little - chance are the horizontal output transistor bit the bust, *possibly* due to the flyback biting the dust. (Usually one followed the other, but not all the time).

Stone, is the NEC you're referring to the one with the little door on top (I think?). If so and the OP isn't interested, I may be, and debating on how South Jersey you are I may not be too far away (philly area).

 

[Stone]

Stone, is the NEC you're referring to the one with the little door on top (I think?). If so and the OP isn't interested, I may be, and debating on how South Jersey you are I may not be too far away (philly area).

Yes, door on top. The first NEC Multisync. I'm 10 minutes from the WW bridge.