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k2x4b524[
May 12th, 2012, 10:42 PM
I know this because at normal brightness everything is blurry, very low brightness everything is fine. What causes this and can I fix it? Or is this almost 25 year old monitor dying a slow death?

Stone
May 13th, 2012, 03:20 AM
Probably the flyback. I have one of those, too, and I never liked it so I'm not too sorry about it's failing. :-) It's got very similar symptoms.

I prefer the original multisync and its Forefront clone which I still have several of that are in excellent condition and available.

njroadfan
May 13th, 2012, 08:08 AM
Open it up and adjust the focus pot. I did that to mine about 10 years ago and its been fine ever since.

Stone
May 13th, 2012, 08:49 AM
Possible, but whenever brightness enters into the equation it's almost always the flyback.

mikey99
May 13th, 2012, 12:14 PM
Could also be caused by aging or weak capacitors in the power supply. If you have a schematic
you could test the power supply output voltages with the brightness at high/low and see if there is
significant variation.


I have a NEC Multisync 2a , is this the same as the NEC Multisync II ?

k2x4b524[
May 13th, 2012, 12:32 PM
It may be, if your 2a about the same size as a 5153? Mine has one 9 pin input on the back, but can take anything from mda to svga signals if you have the right cable. Where would i find the focus pot on this thing? I don't know the first thing about taking a monitor apart to repair it so i don't even know what the flyback looks like, or have a schematic. If i can take it apart to recap it, that i can do, but don't i have to discharge something first?

njroadfan
May 13th, 2012, 12:42 PM
The 2A is VGA only. It doesn't support MDA/CGA/EGA or 15.75khz RGB.

k2x4b524[
May 13th, 2012, 02:42 PM
just checked bitsavers and nada, i'm trying the eveready google and found some things, i may have to open this blind.

And having one shipped to tacoma wa, shipping would be killer, probably way out of my price range.

mikey99
May 14th, 2012, 03:09 PM
The 2A is VGA only. It doesn't support MDA/CGA/EGA or 15.75khz RGB.

Hmm, I was thinking the NEC 2A would do CGA/EGA with the proper adapter. I know the NEC 3D
will do CGA/EGA because the one I purchased new many years ago came with an adapter and the
owners manual also had some mention of this capability.

Stone
May 14th, 2012, 03:40 PM
And having one shipped to tacoma wa, shipping would be killer, probably way out of my price range.From here shipping would be under $100... but not too much under $100. :-)

k2x4b524[
May 14th, 2012, 05:10 PM
Exactly, hence the need to try and fix mine.


From here shipping would be under $100... but not too much under $100. :-)

njroadfan
May 14th, 2012, 07:43 PM
http://ftp.qrz.ru/pub/hamradio/schemes/monitors/nec/NEC-JC-1402/

might want to mirror that FTP, quite a few classic monitor service manuals there.

mikey99
May 15th, 2012, 06:44 AM
Awesome find, incredible amount of info there on old monitors and lots of other stuff too.
.....couldn't find the schematic for my NEC-2A, JC-1403HMA monitor , but looks like almost
every other NEC multisync is listed there....



http://ftp.qrz.ru/pub/hamradio/schemes/monitors/nec/NEC-JC-1402/

might want to mirror that FTP, quite a few classic monitor service manuals there.