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| Title: | Atari ST, TT, & Falcon |
| Notice: | Please read note 1.0 and its replies before posting! |
| Moderator: | FUNYET::ANDERSON |
|
| Created: | Mon Apr 04 1988 |
| Last Modified: | Tue May 06 1997 |
| Last Successful Update: | Fri Jun 06 1997 |
| Number of topics: | 1433 |
| Total number of notes: | 10312 |
40.0. "NEC MultiSync II as color/mono monitor replacement" by LDP::WEAVER (Laboratory Data Products) Fri Apr 15 1988 01:11
NEC MultiSync II to Atari ST
--- --------- -- -- ----- --
Copyright (c) 1988 David S. Weaver
All rights reserved
This file may be copied freely only with the inclusion of the above
copyright notice for non-commercial use.
If you have any questions, feel free to contact the author on
CompuServe (76456,2604) or Delphi (DSWEAVER).
The NEC MultiSync II is a great monitor to buy if you want a monitor
that you can migrate to another system when the time comes that you
need higher resolution color.
The specs are as follows:
NEC MultiSync II Atari
low medium high
------- ------- -------
Horizontal Bandwidth: 15.5kHz - 35kHz 15.8kHz 31.5kHz 35.7kHz
Vertical Bandwidth: 50Hz - 80Hz 60Hz 60Hz 71.2kHz
Horizontal Resolution: 800 dots 320 640 640
Vertical Resolution: 560 lines 200 200 400
Signal level: TTL pos --- --- ---
(analog) 0.7Vpp 75 ohm pos 1.0Vpp 75 ohm
Sync Signal level: TTL pos/neg TTL 3.3K neg
(analog) 0.3Vpp neg --- --- ---
As one can see from the chart, all the Atari specs fall with the NEC's
except for the 35.7kHz (instead of 35kHz) which doesn't seem to be a
problem. Also the video signals are a bit high (1.0Vpp rather than
0.7Vpp), but it seems to be working just fine without the addition of
any resisters. (If you want to add a resister, you would need 107-75
ohms or 32 ohms in series for the RGB signals, if I did my math correctly)
I initially had a problem with the NEC not syncing to high rez mode on
the ST after powering off the monitor and then powering it back on
again. The workaround was to either unplug the video cable, or reboot
the ST. I decided to add a switch to break the horizontal and
vertical sync lines. During the process, I switched the cables I was
using to feed the DB9 connector to some that were more flexible because I
had a problem with the signal lines breaking at the connector. I also
grounded the DB9 connector to the shield ground in the cable from the
Mega ST. As a result of this rework, I found I no longer needed the
extra switch to interrupt the sync signals.
The following pin assignments are what work when connecting an NEC
MultiSync II to a Mega ST2 for color operation, they should work for
any of the ST series:
MultiSync II Mega ST
(female DB-9) (male 13 pin DIN)
pin 1 red pin 7 red
pin 2 green pin 6 green
pin 3 blue pin 10 blue
pin 5 mode control or v sync pin 12 verticle sync
pin 4 h/v sync or h sync pin 2 composite sync
pin 6 red ground pin 13 ground
pin 7 green ground pin 13 ground
pin 8 blue ground pin 13 ground
pin 9 ground pin 13 ground
The Mega ST can also use this combination for sync:
pin 4 h/v sync or h sync pin 9 horizontal sync
pin 5 mode control or v sync * not connected
For monochrome to work, use the following connections instead of
those listed for the same pins above:
pin 1 red pin 11 monochrome
pin 2 green pin 11 monochrome
pin 3 blue pin 11 monochrome
* Connect to pin 13 (ground) if you want to increase the
vertical size on the screen. Not really needed as the
front panel "v size" switch has enough control, and the
image size is big enough with the "v size" switch in the
dentented position.
In addition, you will want to provide a separate RCA jack to provide
an audio out connection, given that the Multisync has no audio
capabilities:
RCA jack ST connection
-------- -------------
audio pin 1 audio out
ground pin 13 ground
I ended up buying a "multisync" cable from Practical Solutions.
The Practical Solutions cable has the following color coding:
Pin Color Function
---- -------------- -----------------------
1 yellow coax audio out
2 black coax composite out (composite sync on Mega)
3 n/c
4 red monochome monitor (ground for monochrome)
5 n/c
6 green coax rgb - green
7 red coax rgb - red
8 blue coax shield +12V (may vary from ST to ST)
9 black horizontal sync
10 blue coax rgb-blue
11 white coax monochrome
12 white vertical sync
The following was verified with an ohm meter:
13 yellow coax shield ground
black coax shield ground
green coax shield ground
red coax shield ground
white coax shield ground
In addition the shield appeared to be grounded as well.
I cut about a 6" length of cable off the cable from Practical Solutions
and used it to wire in a few switches to switch both the monochrome/color
signals and the h/v/composite signals. This cable is much more flexible
than the cable I tried using in my first attempt. By separating the
individual shielded cables from the bulk wrap, you can get some very
flexible/small shielded coax.
The switch box ended up something like the following:
Atari ST pin 4 pole NEC Multisync-II pin
(13 pin DIN male) double throw (DB-9 female)
----------------- toggle switch --------------------
+---------+
| |
Blue Cx 10 - rgb/blue ------- |
| /--------------- rgb/blue - 3
White Cx 11 - monochrome -----/ |
| |
Green Cx 6 - rgb/green ------ |
| /---------------rgb/green - 2
White Cx 11 - monochrome -----/ |
| |
Red Cx 7 - rgb/red -------- |
| /---------------- rgb/red - 1
White Cx 11 - monochrome -----/ |
| |
- n/c ------------ |
| /---------------- ground - 9
Red 4 - mono monitor----/ |
| |
+---------+
2 pole *
double throw
toggle switch
+---------+
| |
Black Cx 2 - comp sync ------ |
| /-------- comp/horiz sync - 4
Black 9 - horiz sync -----/ |
| |
| |
White Sh 13 - ground --------- |
| /--------- mode/vert sync - 5
White 12 - vert sync ------/ |
| |
+---------+
* This switch is purely optional, it allows use of both types
of video sync, and will ground the mode pin to increase the
vertical size when composite sync is switched in.
Red Sh 13 - ground ------------------------ red ground - 6
Green Sh 13 - ground ---------------------- green ground - 7
13 - ground ----------------------- blue ground - 8
13 - ground ---------------------------- ground - 9
Yellow C 1 - audio out --------------------- RCA signal line
Yellow S 13 - ground ------------------------ RCA ground line
shield -------------------------------------- shield
Note: Do NOT connect pin 8 (Blue coaxial shield) to any other
pins/signals. This pin may have +12 volts on it. Make
sure that you insulate the shield very well on this line
so it won't make accidental contact with another signal.
When the cable is all built, use an ohm meter and make sure that you
have no shorts. When you actually want to hook it up to test it, set
the switches on the back of the MultiSync II to the following:
Switch State
manual switch on
mode switch gray (shouldn't matter, digital only)
color mode switch 64 (shouldn't matter, digital only)
Set the switches on the front to the following:
Switch State
v posi adjust after powering on
v size adjust after powering on
h posi adjust after powering on
h size on
text off (shouldn't matter, digital only)
text color white (shouldn't matter, digital only)
Now turn on power and you are on your way. Note that for all of the
cabling of video signals, I used shielded cables (highly recommended)
and soldered all the coax shields together and to the ground pins
(use a smaller braided cable to actually connect between the shields
and ground pins).
# Part# Description Price: Source:
- ----- ----------- ------ -------
1 76108 16-130 1 7/16"x4 13/32"x3 7/32" black box 8.99 A/E
1 69377 904 female RCA connector 0.59 A/E
1 276-1538 female DB9 connector, solder type 2.49 R/S
1 53055 205817-1 female screwlocks (for DB9) 1.49 A/E
1 22104 7401SYZQ 4 pole, double throw, toggle switch 10.99 A/E
1 22048 7301SYZQ 3 pole, double throw, toggle switch 8.09 A/E
1 76292 11-304 5/8" OD, 1/2" ID rubber grommet 0.99 A/E
1 Atari ST "multisync" cable 24.98 P/S
-------
Total: $ 58.61
P/S A/E R/S
Practical Solutions Active Electronics Radio Shack
1930 E. Grant Road 133 Flanders Road
Tuscon, Arizona, 85719 Westborough, MA 01581
(602)884-9612 1-800-343-0874
(617) 366-8899
You will also need various drill bits, solder, and some tool to cut a
hole for the DB9 connector into the plastic end of the aluminum/plastic
box. The grommet is to protect the ST monitor cable entering the box.
Disclaimer:
o This hookup worked for my Mega ST, I make no gaurantees it will work
correctly on your ST.
o I have no connection with NEC, Pratical Solutions, Active Electronics
or Radio Shack.
| T.R | Title | User | Personal
Name | Date | Lines |
|---|
| 40.1 | How's it look..? | ASPEN2::BOIKO | | Fri Apr 15 1988 02:52 | 7 |
| Dave,
Can you tell us how it looks when complete. I'am using a mono
monitor on an ST, and sure would enjoy a larger screen. How's the
resolution hold up in mono or color...?
Thanks for the info..
-mike-
|
| 40.2 | Works just great! | LDP::WEAVER | Laboratory Data Products | Fri Apr 15 1988 19:50 | 21 |
| It is complete. It works great! It has a 13" monitor so it doesn't
add a great deal more, but it is easier to adjust to fill to the
borders if you don't mind screwing up the aspect ratio a bit. You
may also have to adjust the horizontal & vertical position if you
want to have monochrome fill the screen.
I would say the color resolution is as good as any of the Atari
color monitors I have seen, It would have been nice if they could
have played some tricks to fill in the alternate scan lines, but
you get those alternate black lines on the Atari monitor as well.
The monochrome resolution is almost as good as the Atari monochrome
monitor, or better, depending on your perspective. To some extent
it seems to smooth the characters a bit (similar to anti-aliasing).
However, when using WHACK with its tiny characters it doesn't do
quite as well as the Atari monitor. I use WHACK a lot, however,
and I haven't switched back to my original monochrome yet. Hopefully,
I will find the time to bring the monitor to the next A.B.A.C.U.S.
so people can make their own judgments.
-Dave
|