My 15khz Amiga 500 NTSC Monitor list

[Golden Child]

Hi all,

 

I have been collecting a personal list of monitors and projectors that will work with my NTSC Amiga 500.

 

These are units that I have personally tested with either my NTSC Amiga 500 with a buffered VGA adapter or a 15khz tester.

 

So far I am almost to 100 different units.

 

I am also compiling a list of monitors that don't work in my testing.

 

 

Anyway, you can check it out at:

 

https://goldenchild2.blogspot.com/2023/04/amiga-500-ntsc-vga-15khz-monitor-list.html

 

https://goldenchild2.blogspot.com/2023/06/15khz-monitors-that-dont-work-with.html

 

I try to update the pages as I find new monitors.

 

Feel free to check out other pages on the blog, so far it mainly centers around Amiga monitors.

 

 

 

 

[tuf]

Fabulous!  Where have you been my whole life? 

[+OLD CS1]

I have some other Dell monitors to add to your "works" list if you are interested.

[Golden Child]

sure, why not?  I'll make a note as to its source.

 

 

I got started on this when I got a buffered VGA adapter off of ebay and tested all the monitors I had. 

 

I was pretty disappointed when the U2412Mb didn't work for me. 8-(

 

It started getting frustrating when I'd buy a monitor that didn't work.

 

Then I got a 15khz vga tester from pcbjunkie and I was off to the races.  If a monitor works with the vga tester at the 15khz setting, it will work with my NTSC Amiga 500.

[amiman99]

I have couple monitors that work with Amiga:

1. Dell SR2320L

2. Cornea CT1702T -this one is a TV with VGA, SVIDEO, COMPOSITE, DVI Inputs.

 

[Golden Child]

If you don't have a 15khz tester, you can make a 15khz signal with linux, xrandr and cvt.  I like to use my EEEpc 901 with knoppix 9.1.

 

 

So ideally, you should be able to do 720x240 but giving a value of 62 for the refresh rate pulls it much closer to 60 hz.

 

$ cvt 720 240 62
# 720x240 59.95 Hz (CVT) hsync: 15.35 kHz; pclk: 13.75 MHz

Modeline "720x240_62.00"   13.75  720 744 808 896  240 243 253 256 -hsync +vsync

 

a lot of monitors for some reason won't sync to 720 horizontally, so boosting the horizontal resolution can give better results

 

cvt 960 245 61 gets pretty close to 15.7 khz and 262 lines for NTSC.

 

$ cvt 960 245 61
# 960x245 59.87 Hz (CVT) hsync: 15.62 kHz; pclk: 18.75 MHz
Modeline "960x245_61.00"   18.75  960 992 1080 1200  245 248 258 261 -hsync +vsync
 

cvt 1440 has double the horiz resolution as cvt 720 and can give good results

$ cvt 1440 245 61
# 1440x245 59.87 Hz (CVT) hsync: 15.62 kHz; pclk: 28.00 MHz
Modeline "1440x245_61.00"   28.00  1440 1480 1616 1792  245 248 258 261 -hsync +vsync

 

you may try cvt 1440 246 61 but some monitors don't like the 246 but will work with 245

 

 

Many monitors can switch between a cvt resolution and an Amiga signal so that you can set the pixel clock to eliminate banding.

 

https://goldenchild2.blogspot.com/2023/09/getting-rid-of-amiga-500-15khz-banding.html

 

I wrote a little script mycvt which makes it really easy to try different resolutions.

It's easily modified, like setting the output xrandr device to VGA-1 instead of VGA1 for example.

 

 

#/bin/bash
if [ $# -eq 1 ]
then
echo one parameter given, set device to $1
declare -x d=$1
printenv d
#no, child cannot modify env vars of parent but you can run it as source ./mycvt and it will work
#. ./mycvt VGA1 will also work as . is an alias for source
else
echo $*
cvt $*
echo d = $d
if [ -z "$d" ]
then
d=VGA1
echo no device specified, using $d
fi
a=`cvt $* | tail -1 | cut -d' ' -f2-`
b=`cvt $* | tail -1 | cut -d' ' -f2`
echo $a
echo $b
echo xrandr --newmode $a
echo xrandr --addmode $d $b
echo xrandr --output $d --mode $b
xrandr --newmode $a
xrandr --addmode $d $b
xrandr --output $d --mode $b
fi

 

[Golden Child]

and if you try the linux cvt/xrandr, just know that it isn't 100% perfect in matching a true amiga signal.  The pcbjunkie 15khz tester is a very accurate and if it works with the tester, it will work with an Amiga 500 NTSC.

 

Also, you can try PAL resolutions, many monitors that can do 1440x240 will also display 1440x288 signals.

 

I just got a Dell 2001FP and that takes my list up to 100 items.

 

(it's really terrible to have to reset the horizontal position on the 2001FP when it does an auto adjust.  This gets tiresome quickly.)  (I wonder if you could use DDC to set the horizontal position)

Edited November 7, 2023 by Golden Child

[+OLD CS1]

5 hours ago, Golden Child said:

Dell 2001FP

This is one of my proposed additions, as well.  I have found that pretty much any of the Dell monitors with composite/S-Video input will sync to 15kHz on the SVGA.

[Golden Child]

I have a Dell 2407WFP and 2408WFP that have composite and s-video and they won't do 15khz NTSC on the VGA input.  They will happily do 15khz 240p on the component inputs however with a RGBS to YPbPr adapter, and monochrome composite from an Amiga 500 NTSC.

Edited November 7, 2023 by Golden Child

[+OLD CS1]

26 minutes ago, Golden Child said:

I have a Dell 2407WFP and 2408WFP that have composite and s-video and they won't do 15khz NTSC on the VGA input

There are always exceptions and hard-asses.  I should have specified the square 4:3 ones.  The widescreens are hit-and-miss for me, for sure.

27 minutes ago, Golden Child said:

They will happily do 15khz 240p

If you observe closely, you will find even this mode tears.  It will sync to the "240p" signal, but it still treats it as interlaced.  This is a huge bummer for games with a lot of side-scrolling or objects which move from side-to-side, or, even worse, objects which flash on the 60Hz interrupt.  You will see those flashing objects appear solid, not appear at all, or done some weird phasing in and out of our dimension.  Also, different models handle edges and curves differently on these composite modes.  Fun stuff.

[Golden Child]

What games are the worst offenders?  I've been using Great Giana Sisters as my game test.

 

It shouldn't be too hard to whip up a little scrolling/flicker test in AMOS.

 

[Shift838]

Here is the monitor that I use on my A500 and Atari ST via VGA.

 

Dell 22 Monitor - P2222H 

https://www.amazon.com/dp/B096W3MV83?psc=1&ref=ppx_yo2ov_dt_b_product_details

 

[+OLD CS1]

15 hours ago, Golden Child said:

What games are the worst offenders?  I've been using Great Giana Sisters as my game test.

 

It shouldn't be too hard to whip up a little scrolling/flicker test in AMOS.

Mega Ball, Deluxe Galaga, Shadow of the Beast.  Usually fast-moving objects, so the parallax in Beast does not cause issues.  These are ones I have played on my LCD monitors in 15kHz.  I have FF/SD for all of my gear now, and I figured out about my monitors by accident, using a Commodore RGB-SVGA adapter on my 1200 at VCF several years ago.

[Golden Child]

17 hours ago, Shift838 said:

Dell 22 Monitor - P2222H 

 

 

Thanks, Shift838, I'm going to get a P2222H and see how it works

[Golden Child]

14 hours ago, OLD CS1 said:

Mega Ball, Deluxe Galaga, Shadow of the Beast.  Usually fast-moving objects, so the parallax in Beast does not cause issues.  These are ones I have played on my LCD monitors in 15kHz.  I have FF/SD for all of my gear now, and I figured out about my monitors by accident, using a Commodore RGB-SVGA adapter on my 1200 at VCF several years ago.

Yes, Shadow of the Beast has a lot of those flickery effects.  SOTB was the greatest graphics and sound demo for the Amiga when it came out.  Not anymore by today's graphics standards, but at the time it was soooooo cool.  Coming from an apple II the Amiga was a revelation.

[Golden Child]

Another thing I found while searching the internet is that they make industrial monitors with "slow-scan" legacy capabilities, which will handle 15khz type signals.  You can search on "slow scan legacy 15khz" and find a few hits.  Those monitors are out of my price range as I buy most of my stuff used at thrift stores and computer recyclers.

 

I've also wondered about buying an LCD controller board kit that would support 15khz and pair it with a suitable LCD panel (even a used panel from an existing monitor).

 

I've also seen some arcade monitors for sale like a 32 inch Arcooda LCD Arcade Monitor 15khz 31khz to 1080P Description

There are also https://www.retrorgb.com/43-lcd-arcade-monitors-15khz-31khz.html

 

[Golden Child]

I left an LCD monitor on Amiga interlace for awhile and the flicker caused an afterimage to form.  After an hour or two of non-interlace, the "burn-in" went away.

 

I wonder if the LCD gets "fatigued" and needs a rest.

 

So maybe try to refrain from long periods of using interlace.

 

 

from https://forums.blurbusters.com/viewtopic.php?t=7539

 

Image Retention ("Temporary Burn-In")
From Temporary Static Electricity Buildup In Pixels

Flicker patterns such as:
- Emulator black-frame insertion
- 3D-glasses software
- Certain motion tests (including but not just TestUFO's Sync Track)
- Anything that does exactly a half-Hz or quarter-Hz flicker with no dropped frames for a sustained period

Can create temporary LCD image retention. It's a static-electricity behavior when a flicker goes in sync with the positive-negative voltage inversion algorithm, and creates this inversion-related image retention.

This is temporary and you just display video full-screen, or some other thing that really exercise the whole screen -- e.g.
This gets rid of the per-pixel static electricity buildups.

You also get the same problem in anything that flickers pixels in-phase with the positive-negative voltages of the LCD inversion algorithm.
 

 

 

[Golden Child]

Ok, got a Dell P2222H, and I can say that it works with my Amiga 500 NTSC and is very nice.  It's got a joystick control on the back.  It came with a pivoting stand.

 

It does clock=100, but it has sharpening so the image is crisp.  Interlace still looks bad, but I never use interlace anyway.  (haha)

 

Thanks to Shift838 for the pointer!
 

Edited November 14, 2023 by Golden Child

[Golden Child]

Added a few more to my list, I'm up to over 110 different monitors.

 

Today I found an Asus VG245H that works with a 15khz tester.

[Golden Child]

I saw this video on youtube from Chris Edwards about the GBS-8200:

 

 

I thought I'd see what the GBS-8200 could do, so I bought one on ebay.

 

It has 3 inputs RGBHV, RGBS and YPbPr.

 

Unfortunately, the RGBHV input doesn't work with my 15khz Amiga 500 NTSC output to an buffered VGA adapter .  According to the manual, RGBHV has to be 31Khz.  RGBS will accept 15khz.

 

So you have to build a cable that will take the composite sync off of the DB23 instead of the H and V sync which the unbuffered VGA uses.

 

Using an ASUS eeepc it would display 720x480 just fine off of VGA and the RGBHV input.

 

 

I had a RGBS to YPbPr adapter and it will accept 15khz on that input just fine with deinterlacing:  Amiga 500 NTSC DB32 -> buffered VGA -> RGBS to YPbPr adapter -> GBS-8200 YPbPr input -> VGA monitor.

 

I scanned the GBS-8200 manual and put it on archive:

 

https://archive.org/details/gbs-8200-manual

 

It looks best if I set the GBS-8200 to use its maximum resolution 1360x768.

 

Oddly, I couldn't seem to do any geometry adjustments, pressing the button to select the geometry menu does nothing.

 

[Daedalus2097]

It's worth pointing out that GBS-Control is a hardware/firmware modification for the GBS-8200 that makes a dramatic improvement to its functionality. You can read it here: https://ramapcsx2.github.io/gbs-control/

[Golden Child]

Some Dell monitors can sync on green SOG, and they can also switch to using YPbPr colors.

 

I got a cable that goes from 3 component RCA leads to VGA, and the Dell E2414 will sync on green and display properly with the YPbPr colors.

 

Using an Amiga 500 NTSC --> Buffered VGA Adapter --> VGA to YPbPr converter box (RGBS to YPbPr) -->  3RCA to VGA cable to the Dell E2414 it looks pretty good.

 

(using the converter box as shown here) https://goldenchild2.blogspot.com/2023/04/amiga-500-ntsc-to-component-video.html

 

You can also take the a500 mono composite out (which is basically Y) and plug in the green component lead (of the 3RCA to VGA cable)  and the E2414 will display mono green (grey when you switch it to YPbPr colors).

 

 

Note that not all Dell monitors will sync on green, but I've found a few that will, like the P2219.

[+OLD CS1]

2 hours ago, Golden Child said:

Note that not all Dell monitors will sync on green, but I've found a few that will, like the P2219.

Nice finds.  I am having difficulty finding the non-H models when I search.

[Golden Child]

31 minutes ago, OLD CS1 said:

Nice finds.  I am having difficulty finding the non-H models when I search.

Sorry I should say P2219H to be more precise.  I just fired up the P2219H and it says "P2219H" on the screen.

 

They're nice little units, not heavy, and display nice sharp 640x200 Amiga NTSC.  640x400 interlaced isn't great, but it's enough to use it to put yourself back into non interlace.  I actually have 2 of them.

 

 

 

 

[Golden Child]

One thing of note when you're using one of the RGBS to YPbPr converters, the sync signal can be unstable in interlace on some TVs.  It depends on the TV brand and model.  Since the a500 NTSC has a mono composite out which is basically the Y channel, I can use that as the Y channel and take the Pb and Pr off of the converter, and that is rock solid on some TVs.