NEC Multisync 3D with Non-VGA Adapters

[chalackd]

So, I've been fooling around all week here trying to get my Multisync to work with CGA and MDA video adapters to no avail. I scoured the web looking for pinouts to make an adapter cable, and with nearly 10 different configurations found no solution... (Including a couple listed here on the forums, for Multisync II and Mitsubishi DiamondScan monitors)

Finally I had to resort to paying for a membership to some service manual site to get a scanned copy of the service manual related to this particular monitor. It wasn't obvious, but hidden away in the back with the circuit schematics was a small chart with the information I was seeking.

In the interest of saving the next guy all the trouble I just went through, here's the wiring required to adapt D-Sub 9 MDA, CGA, EGA, and PGA/PGC to the D-Sub Mini 15 of the monitor

D-Sub 9 > D-Sub M 15

1 > 1
2 > 2
3 > 3
4 > 13
5 > 14
6 > 5
7 > 15
8 > 12
9 > 10

I've tested this layout with both CGA and MDA cards and it works perfectly, the manual lists the same wiring for both EGA and PGA as well, but I'm lacking these cards to verify it myself.

The only special thing to note is that when using MDA the "MODE" switch on the front panel of the monitor must be set to "ON", for all others it is set to "OFF"

Hopefully this saves somebody a hassle :D

 

[mikey99]

NEC 3D , thats a very nice monitor. I had a NEC 3D that I bought new back around 1988.
I recall paying over $600 for that monitor Unfortunately it died and I tossed it many years ago.
Later when I started collecting vintage computers I wished I would have kept that because it would
probably have been repairable.

I do have a NEC 2A Multisync that I picked up recently, which is the predecessor to the 3D.
I would think that the pinouts would be the same. Does that site list a service manual for the 2A as well ?
If they do I would really like to get a copy or even a copy of the 3D manual in case I ever find one that needs
repair.


Thanks for posting that info.

 

[chalackd]

No sign of a service manual for the 2A, but there is one for the 2V (Model JC1432) which may or may not be similar...

 

[mikey99]

I was digging through some parts boxes I had last night and came across this adapter.
I think this actually came with the NEC 3D , fortunately I saved it and will be trying this with my
NEC 2A. I tested with a continuity checker and the pinouts of this match your
earlier post exactly.

 

[chalackd]

Nice find, I wish that I had one of those to go with mine, but I got this monitor years ago as a hand-me-down with an IPC 286 when they were only considered to be "obsolete junk" and the original adapter was long gone...

I've got some connectors on the way though so I think that I'll make myself a couple little adapters like that, maybe I'll try to cast them in epoxy or something to make them nice and compact/durable.

 

[mikey99]

I wonder if the metal shroud like the one on this adapter can still be purchased. If you could find
that it would be easy to duplicate this adapter.

EDIT: I did find some similar 'hoods' in a Google search for "dual entry d-sub hood"
but its not clear if these allow 2 D-sub connectors to be mounted.

 

[chalackd]

Dual entry hoods typically seem to allow two cables into a single connector.

I did manage to find some 'metalized plastic' dual connector hoods, which I assume simply means chrome plated plastic. Definitely not to the same level of quality as the original metal housing, but they should be suitable for the task.

Now if only I could find a hood matching de-9 to da-15 connectors I'd make some multisync to IIgs one-piece adapters too...

 

[Ken Vaughn]

Very interesting. Is there something about the NEC Multisync 3D which allows this to work?

I have a couple of Sony Multi-Scan monitors (a CPD 1304) and (a CPD 15SF1) and I have always wondered if there was any way to hook them up to CGA/MDA adapters. I was always told that the answer was no -- but your post has me wondering.

 

[mikey99]

The capability is specific to the NEC 3D , the monitor can handle TTL or analog signals .
There may be other multisync monitors that have these capabilities also, I recall seeing a
list on the internet somewhere......

From the NEC 3D User Manual :
"The Multisync 3D Color monitor offers both TTL and Analog signal inputs"
"The Multisync 3D is compatible with the IBM MDA, IBM CGA, IBM EGA, IBM PGC...."

 

[chalackd]

As far as what I've heard in the past there has only ever been a handful of VGA monitors capable of handling the lower horizontal scan rate and TTL signals from earlier video formats. The original line of NEC MultiSync monitors (Including the first MultiSync, MultiSync II and MultiSync 3D) seem to be some of the better known, but I have also heard of reference to Mitsubishi and Sony having had a couple compatible monitors.

This page, http://www.best-electronics-ca.com/monadapt.htm has a list at the bottom of various monitors from various manufacturers that are capable of handling the 15khz and up horizontal scan rates required by older formats, but their TTL support is unknown to me. Arcade machine enthusiast sites seem to be a good resource for finding such monitors, both with lower frequency and TTL support...

In fact there are still a few places where you can buy a modern flat panel monitor that will support the 15+khz and TTL, they seem to be mostly aimed towards the industrial sector, but would probably make some nice workbench monitors for working with everything from MDA to the currently popular HD1080.

According to a quick search the Sony CPD 1304 mentioned above works at 28-50khz h-sync and the CPD 15SF1 at 31-64khz h-sync. This leaves both of them a bit above the requirements for MDA (18.43kHz), CGA (15.85kHz), and EGA (22kHz). Though the 1304 should work with a PGC (30.48kHz).

 

[mikey99]

I have a Mitsubishi AUM-1381 VGA multisync which also works with MDA/CGA/EGA.
The Mits has separate input connectors on the back for the VGA and CGA/EGA so its
more straightforward to hook up since it doesn't need an adapter... just a 9 pin serial
cable works fine. I had this one opened up awhile back to clean the dust out and
snapped a few pictures......has a few cracks on the front bezel but it works well.

 

[chrisNova777]

sorry to bump an old thread but - is there any models where its possible to use a 9pin to 15 pin with a nec multisync LCD? (For conecting an old EGA card to an LCD)
or does multisync have a completely different meaning when speaking of an LCD vs a CRT?

 

[modem7]

sorry to bump an old thread but - is there any models where its possible to use a 9pin to 15 pin with a nec multisync LCD? (For conecting an old EGA card to an LCD)
or does multisync have a completely different meaning when speaking of an LCD vs a CRT?

There are some specialist LCD monitors that can handle EGA, such as the example at [here], but the vast vast majority of LCD monitors will be VGA only.

An alternate solution is the use of an EGA-to-VGA converter. A related thread on this is [here]. Looking at some other related threads, the quality of some converters is low.

 

[Stone]

I have one original NEC MultiSync I, Model JC-1401P3A that's available and in excellent condition if there anyone interested.

 

[TamaMan]

D-Sub 9 > D-Sub M 15
1 > 1
2 > 2
3 > 3
4 > 13
5 > 14
6 > 5
7 > 15
8 > 12
9 > 10

I have built an adapter according to the above mentioned instructions (I used an existing DB9F to DB9F adapter for the case) but I am unable to get MDA or CGA working on my recently acquired NEC Multisync 3D (JC-1404HMED) CRT and Kaypro PC with ATI Graphic Solution P/N 168228 card.



I have checked the wiring with a multimeter. Unfortunately, I don't have a working mono (or RGB) monitor to verify the Kaypro PC output but previously the mono signal was been working with a Kaypro branded Samsung monochrome monitor. And when configured for RGB, the composite pins on ATI card show clear picture via composite.

Here is what I've tried:

MDA

---

Kaypro PC DIP switches (on the CPU board):
2 OFF
3 OFF

ATI Graphic Solution Rev.3 P/N 168228 DIP switches:
1 OFF/OPEN (tested with ON also, same difference)
2 OFF/OPEN
3 ON
4 OFF/OPEN
5 OFF/OPEN
6 OFF/OPEN
7 N/A
8 N/A

NEC 3D:
MODE ON (tried OFF also)

Result:


CGA

---

Kaypro PC DIP switches (on the CPU board):
2 ON
3 OFF

ATI Graphic Solution Rev.3 P/N 168228 DIP switches:
1 OFF/OPEN
2 ON
3 ON
4 OFF/OPEN
5 OFF/OPEN
6 ON
7 NC
8 NC

NEC 3D:
MODE OFF (tried ON also)

Result:


Any tips on where to start troubleshooting this? Basically I would like to know that the NEC 3D is working OK with the CGA/MDA signals.

 

[TamaMan]

Got it finally working! Tip for future builders: I recommend getting connectors with clear pin number labels as this adapter involves both male and female connectors..

Here's Sierra Online's King's Quest PC booter on a Kaypro PC w/ATI Graphic Solution Rev.3 in RGB mode:

NEC 3D's COLOR set to "AUTO":


NEC 3D's COLOR set to "8":


The COLOR selection is a nice feature to fix the annoying "wrong" CGA colors on non-IBM PCs.

Thanks to chalackd for providing this wiring information!

 

[1ST1]

There are some specialist LCD monitors that can handle EGA, such as the example at [here], but the vast vast majority of LCD monitors will be VGA only.

That is not exactly true. To get all 16 colors of CGA/EGA you need to mix RGB signals with intensity. This was already succesfully tryed with Olivetti M24. See http://www.vcfed.org/forum/showthread.php?65253-M24SP-DB25-to-DB9-adapter/page3

 

[Armitage]

Hopefully this saves somebody a hassle :D

Thanks for this, it indeed saved me some hassle (12 years later)! I just picked up a MultiSync 3D with only the HD15 connector. I built a CGA adapter using your pinout and it works great!

 

[seat safety switch]

I am having a little bit of trouble with connecting the NEC MultiSync 3D to my Apple IIgs. As far as I can tell, I should be able to get away with this pinout:

IIgs pin	Signal	MultiSync 3D pin
1	Red ground	6
2	Red	1
3	Composite sync	13 (VGA H.Sync)
5	Green	2
6	Green ground	7
9	Blue	3
13	Blue ground	8

I tried to follow the VGA pinout as closely as possible on the MultiSync 3D side, and left every other signal floating, including V.Sync on pin 14.

I don't get any picture on the monitor (I got a flicker of a fairly legible one, but with bad horizontal sync, when changing the "mode" switch on the front – only briefly.)

The monitor seems to work OK with Mac RGB sources (using one of those dip-switch adapters) as well as digital RGB sources (using a modified version of the CGA pinout, thanks chalackd.)

This is the first composite-sync source I'm trying with the monitor. Reportedly, the MultiSync 3D works with the Mac adapter that came with the monitor, but I haven't seen any evidence that the DIP-switch-free MultiSync "Mac adapter" is the same thing as my DIP-switch-laden Mac adapter. If you have one of the ones that would have shipped with this monitor, I would appreciate any help buzzing it out.

In my reading, I saw that the TULARC FAQ mentions that you can adapt the IIgs to the MultiSync II, but not the IIA. I'm not clear on what the difference is between those two monitors, and if it applies at all to my 3D.

 

[seat safety switch]

I am having a little bit of trouble with connecting the NEC MultiSync 3D to my Apple IIgs.

Doing an update here since I can't edit my original post.



The problem turned out to be that I had to tie the shields of the connectors together. Usually you can "get away with it" with VGA monitors, but the MultiSync is not truly a VGA monitor. You can grab the adapter on my GitHub here, if you're one of probably three people on the planet who want to use a IIgs with a MultiSync 3D (if you are, message me! I bet we can be best friends.)