NEC 3D image collapsed vertically

I'd start by getting a circuit diagram, then you can check varous voltage points in the horiz scan section.

none of your newer ones will do 15kHz horiz? I'm surprised, most bog standard 17" ones will do that.

NT

On Mon, 19 Feb 2007 19:18:22 +0100, anonymous put finger to keyboard and composed:

Look for dry electrolytic capacitors in the vertical section. Otherwise, if your chassis uses discrete transistors for the vertical amp, then check those. The worst case scenario is a bad yoke.

- Franc Zabkar

Or if you want a working NEC 3D I'm about to toss.....

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Not any I've seen that were made in the last decade or more. The last VGA monitor I had that was capable of 15 KHz was a Sony CPD-1302 made circa 1988.

anonymous ha escrito:

classic symptoms of bad caps in the vertical section. just replace them

-B.

I stand corrected, had forgotten to take interlacing into account. Can the OP not use a TV?

NT

Thank you (and everyone else) for your advice. I indeed think it has something to do with a bad capacitor or transistor... Alas, without a schematic, it's like searching with blindfolded eyes. I therefore wrote to NEC, and I hope they will provide me with a schematic...

Regards,

Thierry Godefroy.

On Thu, 22 Feb 2007 20:16:37 +0100, anonymous put finger to keyboard and composed:

I don't know if it's the same beast, but a service manual with circuits for an NEC Multisync 3D (model JC-1404) is available for free download (in four parts) from here:

If your monitor has an LA7835 vertical output chip, then change the capacitors nearby.

- Franc Zabkar

WOW ! Cool ! Many thanks: that's excatly what I was searching for ! :-)

Best regards,

Thierry Godefroy.

was this the one that the electrolytic capacitors leak and hurt traces on the multi layer main board...

if you see physical, electrolyte leakage on the board, it is, and you must be careful because the traces are very small ... usually require jumping some with wire...i tried to get one going once like this and i gave up ... the degree of damage can vary alot and mine was a pretty bad one