Neotec NT-2702 SP with an odd neck board looking for manual or info or more

[Acpowell]

I bought a Neotec NT-2702 SP thinking it would just need a cap kit as that is what the seller had mentioned.  I get the capkit for the monitor I have and have my friend come over to help and we realize that the cap kit is missing to caps.  Not necessarily because it bought the wrong one but because the neck board doesn't match what both 2702 manuals I have says is supposed to be there.  The neck board model is a NT-96-02.  What I find most weird is that this is a Full Family Version but the VGA connector at a moelx plug rather than a DB15.  I was able to get the monitor rewired and connected but it obviously needs some help.  I am going to buy the missing caps based off what is currently installed but I was hoping to get a proper manual for it.  I believe it came out of an Atari Road Burners game.  I've looked at the game manual online and it mentions the monitor but nothing special about it.

Any help would be great.

[lilshawn]

there is really nothing particularly special amongst the 2700 2701 and 2702 units. the difference lies in the tube/yokes that they are connected to and how the chassis drives the yoke.

a lower B+ is used for lower frequencies and a much much higher (often 2x the voltage) is needed to drive a high frequency. this is why monitors of this era were often separate units for separate frequencies. (standard/medium/high)

it wasn't until monitors were designed with microcontrollers that could safely switch and regulate the power levels needed for different frequencies... that multimode or tri-res monitors became more popular.

IIRC the 2702 came with a VGA cable that plugs directly to the neck board at P901 or could be fed a signal into the "molex" header with an adapter and the regular wire bundle that comes with the 2700/2701.

it's not uncommon for cap kits to be missing caps. you don't usually have to replace every single one. often there are some that just hardly ever go bad (main filter cap)... are prohibitively expensive to include in a kit (which would likely double or triple the cost of the kit) or are plain old not available any more. (looking at you high voltage bipolars)

as far as what's going on with your neck board... no idea. gonna have to post a pic or something. maybe it's a different revision.

[Acpowell]

as far as what's going on with your neck board... no idea. gonna have to post a pic or something. maybe it's a different revision.

I will post a pic of the neck board.  I guess it is just frustrating that the kit I bought didn't include the right cap for a given spot (of course that cap is obviously one that needs replacing).  I am not placing blame on anyone just annoyed.  I guess it comes with the territory given the hardware I am working with.

It doesn't help either that the person who did the cap rebuild previously completely flubbed the whole thing.  Because of some hand issues I am having a friend help me, and I can't count home many traces we've had to repair because of a crappy solder job by the previous person.

[Acpowell]

Here is the photo (what I have) and drawing (what the manual says I should of had) of the neck board I have which is NT-96-02.  The manual lists a NT-9710.  Not sure what that means or even if it matters.

[lilshawn]

which cap was it that was wrong? sometimes they will change a value to improve reliability... for instance, on some chassis the startup delay capacitor is upped from 100 uf to 220uf to delay the startup a little longer to allow the B+ to charge up and stabilize.

going up in voltage is fine... going up in uF is sometimes okay, provided you know what it's purpose is. if it's power filtering... it's okay to go up a bit... if it's timing, not so much.

that neckboard looks fine. if you note, the 2 sets of wires (P902 P903) look to be still held down by the factory silastic.

you just need to find the cable that plugs into P901. this is the VGA cable. it's nothing special, if you can find a connector to plug into position P901, you can hack a VGA cable to work with it.

[Acpowell]

which cap was it that was wrong? sometimes they will change a value to improve reliability... /you just need to find the cable that plugs into P901. this is the VGA cable. it's nothing special, if you can find a connector to plug into position P901, you can hack a VGA cable to work with it.

I cannot remember the caps that were wrong, they were on the neck board.  We just bought caps to match what was already there..  We just finished installing everything and putting the boards back in.  The color is better, the ghosting is gone, but the picture still seems off; almost too dull.  It could be that I have a color profile active that I need to shut off (left over from the LCD) but I am not sure yet as I quit for the evening because I was tired.  I had already made a cable for the VGA and had that working day one (see attachment) it works well but could be contributing to the monitor not looking the best.  I would love to find the correct adapter without having to build one but beggars can't be choosers.

It was recommended to be to have the CRT rejuvenated so I am trying to research that now.

[ed12]

u are aware that ever other pin of the vga input is grounded right ?
so it would go
r in
r ground
blue in
blue ground
green in green ground
i have seen where making these cables and leaving the (r/g/b sheild=ground) out and tied just to common
cause the exact same problem u are having

ed

[Acpowell]

u are aware that ever other pin of the vga input is grounded right ?
so it would go
r in
r ground
blue in
blue ground
green in green ground
i have seen where making these cables and leaving the (r/g/b sheild=ground) out and tied just to common
cause the exact same problem u are having

ed

**just combined multiple posts into one**

Hmm possibly not.  So I just took and read the manual to see what each wire was and put them into the VGA connector.  I am not sure how I would wire it based on what you just told me. 

this is the diagram I used, although I didn't short all the pins together that are touching the black wire.  Is that what you think I should do?
http://www.geocities.ws/podernixie/htpc/vga2arcade.gif

Going off the attached picture I split off the Yellow and white wire and gave them their own pins.  Should I just short the pins in the diagram that have lines on them?  Sorry I am very new this this stuff.

[Acpowell]

delete please

[ed12]

well i was going off of what i seen in the picture posted
clearly u can see g/e/r/e/b/e/e/v/h
so it tells me they want shield right up the neck board connector

ed

[Acpowell]

well i was going off of what i seen in the picture posted
clearly u can see g/e/r/e/b/e/e/v/h
so it tells me they want shield right up the neck board connector

ed

The issue is that there are only six wires coming out of the plug that came with the monitor.  I guess I will try shorting the grounds together and see what I get.

[ed12]

i will chk in my warehouse
i think i have a neo there ?

but cannot hurt to tie the grounds

ed

[Acpowell]

i will chk in my warehouse
i think i have a neo there ?

but cannot hurt to tie the grounds

ed

That would be awesome, I am dying to be able to just sit and play games with out worrying about what is wrong.  I'd be in your debt. 

[lilshawn]

AFAIK, the VGA cable plugged directly into P901 on the neck board. not at a molex connector.

like so:

[ed12]

yes shawn that is exactley what i always see on these

ed

[Acpowell]

AFAIK, the VGA cable plugged directly into P901 on the neck board. not at a molex connector.

like so:

The one on my monitor is.  That is why my original post said it is an odd ball. The guy I bought it from didn't seemed shocked he said he has seem them before like that.  He just cannot get back to me until Sunday.  So I need to duplicate what you have or wait.  I hate waiting

[Acpowell]

I rewired the VGA connector tonight. It really didn't make any difference whatsoever. I need to turn the red drive up all the way up or I don't get any red it all so I'm not really sure what's going on. I've adjusted everything I know to adjust but I'm at a loss now. Green and blue do not need but maybe half a turn. I'm also not super familiar with the terms. So if it's not the drive I've adjusted  I apologize for naming it wrong   

I apologize, I posted that on my phone during a late frustrated evening.  I will re write it so it makes more sense.

I re-wired my VGA adapter so that more of the ground wires were in place.  I had thought about wiring it directly into the connector that came with the monitor but the connector didn't have pins in all the holes so that wasn't an option for me.  I opted to add wires to pins 8, 7, 6, and the outer shielding then solder them all to the plug end of pin 10 that I had already put in place originally.

This made little to no difference on the quality of the colors.  On a whim/friends suggestion I tried a different video card.  This did make a slightly noticeable difference.  While displaying a color bar, bars 1 and 3 usually looked the same.  With this new card they were slightly different however I still couldn’t get the colors exactly the way I wanted them and they were still “dull”.  I realized through some trial and error it was the VGA to DVI adapter that made the picture slightly better, not the video card.

With the original card back in and the higher quality adapter in place I have decent colors (not great) that are dull.  I now also seem to have a convergence issue. It is extremely noticeable in the upper right corner but also in other parts of the screen.

Also through this whole process the RED gain needs to be up all the way or I cannot see any red at all and I cannot seem to get that to change.  Green is usually just short of half way and blue changes with drive changes. 

All that said, I am not sure if this is a lost cause or if I need to replace something else.  I have been told a rejuvenation might help but I am not sure.

[lilshawn]

how is the convergence in the middle? is it okay there? convergence is usually off in the corners. (not this much though)

the wells gardner k7000 service manual has a good explanation on how to adjust the convergence.

be warned, you can end up making things pretty ugly when you start messing with the convergence.

[Acpowell]

how is the convergence in the middle? is it okay there? convergence is usually off in the corners. (not this much though)

the wells gardner k7000 service manual has a good explanation on how to adjust the convergence.

be warned, you can end up making things pretty ugly when you start messing with the convergence.

It the middle it seems way better.  I did kind of try and mess with the convergence rings but I chickened out and put them back to where the marks were.

[lilshawn]

I find if the convergence is off, it's usually because the yoke has been knocked and is loose or broken.

a bit of silicone and some presure is usually all it needs

[Acpowell]

I find if the convergence is off, it's usually because the yoke has been knocked and is loose or broken.

a bit of silicone and some presure is usually all it needs

I guess I'll have to research that.  I will post a photo of the NEO-GEO cross hatch test screen so you can see what it looks like.  The top red seems off the bottom green seems off (could be the other way around, I cannot remember)

[Acpowell]

Sigh.....

I just tried adjusting the yoke but the plastic is so brittle that every time I look at it wrong plastic breaks off. I even took the nut/band completely off.

How the hell do I loosen it from the tube?!

I regret this purchase more and more. ☹️