ScanJuggler XAGA Lite work with 60-85Hz VGA CRTs?

[studio460]

A little confused on the 50Hz CRT requirement. Or does that apply only to the composite video-out/RF-modulator? I bought a European A1200 (I'm in NTSC-land in the US), so does that mean it's a 50Hz "PAL" machine, or again, does that only refer to the composite video/RF-modulator output?

Will the ScanJuggler XAGA Lite at its native 768x580-resolution work with most 60-85Hz "multisync" VGA CRTs without issue?

[studio460]

Okay, I went ahead and bought a Compaq FS7600e 17" flat-CRT off eBay. It was only $69.99, and brand new in the box (NOS). I jumped on it because it's a 5:4 aspect-ratio display, it was cheap, it's a CRT, and it's new. It supports 1280x1024 @ 60Hz, so hopefully it works with the ScanJuggler's output.

[studio460]

Compaq FS7600e 17" flat-screen 5:4 CRT monitor.

[studio460]

Found this in another thread here:

Originally Posted by ajk

Ordinarily the Amiga output is RGB (separate red, green and blue signals unlike composite or s-video) at about a 15kHz scan rate, which is a traditional video/tv signal. VGA is also RGB, but the scan rate is higher, about double, and therefore many/most modern monitors only accept 31kHz or higher. A scandoubler, in the most basic sense, doubles the scan rate so that these monitors can be used . . .

So with the ScanJuggler XAGA Lite scan-doubler, I should be getting an RGB signal output at 15kHz x 2 = 30kHz [edited for accuracy], so it's likely I should have no problem with the monitor above, right?

I bought a PAL A1200 and live in the US, but the difference between an NTSC and PAL in an A1200 is insignificant isn't it since it's switchable—is that right? Is it only prior models which had an NTSC/PAL-specific Agnes chip? Now, it doesn't matter if I have an NTSC or PAL machine (except for the composite-out and RF-modulator), am I correct ?

[hooverphonique]

I think you're confusing the horizontal and vertical refresh frequencies.. PAL/NTSC uses ~15kHz horizontal refresh, VGA modes are usually higher. PAL uses 50Hz vertical refresh, NTSC 60Hz.

[studio460]

Okay, I am confused. I know PAL is 50Hz and NTSC is at 60Hz, but everyone always mentions this 15kHz number when speaking of displays compatible with the Amiga.

If I'm using the scan-doubler's VGA output, then everything should just work on a 60Hz-capable monitor [edited for accuracy], right (regardless that it's coming from a PAL A1200)?

[studio460]

Found a related comment from another thread, replying to someone who owns an A2000:

Originally Posted by Marchie

. . . Jumper J102 will boot into PAL or NTSC with an 8372A Agnus (most other Agnus versions are dedicated PAL or NTSC).

3.1 ROMs allow you to hold down both mouse buttons on boot and choose PAL or NTSC (regardless of how you set J102). This will make the machine display a PAL resolution (and frame rate I think?) but won't change the timing of your actual machine [emphasis added]. I don't know how this affects games, but if you're trying to genlock for example, you will need to change the crystal as well.

[britelite]

Originally Posted by studio460

Okay, I am confused. I know PAL is 50Hz and NTSC is at 60Hz, but everyone always mentions this 15kHz number when speaking of displays compatible with the Amiga.

50/60Hz is the vertical refresh rate, and 15kHz is the horizontal. Both PAL and NTSC have 15kHz horizontal refresh rate, but have 50 or 60Hz vertical refresh rates. The scandoubler doubles the horizontal refresh rate, from 15kHz to around 30kHz, so a VGA-display is able to show it.

If I'm using the scan-doubler's VGA output, then everything should just work on a 60kHz-capable monitor

Forget about that 60kHz number, it's only something you've mistakenly made up

[studio460]

So, do you think the monitor should work, then? I work in TV and I should know this, but the horizontal refresh rate is something we've never concerned ourselves with. Whatever I typed I gleaned (mistakenly or not) from others' posts (i.e., "Most monitors won't scan as low as 50Hz" [edited for accuracy]). What are they alluding to?

The one thing I was trying to also determine, is that there are in fact hardware differences in the Agnus chips between NTSC and PAL Amigas. But that's mostly irrelevant to the majority of applications?

[britelite]

Originally Posted by studio460

So, do you think the monitor should work, then?

I'm guessing it will work, but might of course be that it doesn't properly sync down to 50hz.

(i.e., "Most monitors won't scan as low as 50kHz"). What are they alluding to?

You're probably mixing Hz and kHz up again. Either they're saying screens won't sync down to 50Hz or 15kHz, both which are true for many flat screen monitors.

[studio460]

Oh, gotcha (I think). Thanks! Wait . . . because its vertical sync won't go down to 50Hz because that's what a PAL Amiga needs to see? I found this thread here very helpful (and possibly where my confusion began about 60Hz/15kHz).

[hooverphonique]

Originally Posted by studio460

Oh, gotcha (I think). Thanks! Wait . . . because its vertical sync won't go down to 50Hz because that's what a PAL Amiga needs to see?

The Amiga doesn't care/need to see anything. The PAL-compatible modes are 50Hz (vertical); some vga monitors don't like to go much below 60Hz, and thus will not display pal, scandoubled or not.

[studio460]

Originally Posted by hooverphonique

The Amiga doesn't care/need to see anything. The PAL-compatible modes are 50Hz (vertical); some vga monitors don't like to go much below 60Hz, and thus will not display pal, scandoubled or not.

Okay, great, I think I get it now. Seeing that I can run a "PAL Amiga" in NTSC mode (soft-switchable, right?) regardless, there's really no issue to owning a PAL Amiga unless I'm genlocking to some old NTSC hardware or something (because the Agnus' clock will still be "wrong," even if soft-switched to "NTSC").

[studio460]

Compatible analog RGB flat-screen CRTs for Amigas equipped with scan-doublers:

So I've been on the hunt for 50Hz-capable CRTs for my coming ScanJuggler XAGA Lite-equipped A1200. Specifically, flat-screen, non-widescreen CRTs with plain, "modern-looking" bezels.

So I have two monitors here: The Compaq I already purchased, but not yet received, and a Samsung. The cool thing about the Compaq is that it's brand new (NOS). I was finally able to find the Compaq's complete refresh specs from a broken Javascript page on Best Buy's site, and the Samsung's specs from an old Newegg page (both sources are linked below):


Compaq FS7600e

• Compaq FS7600e 17" flat-screen 5:4 analog-RGB CRT:

• Horizontal frequency-range: 30kHz-70kHz
• Vertical frequency-range: 50Hz-160Hz

• Samsung SyncMaster 997MB 19" flat-screen 4:3 analog-RGB CRT:

• Horizontal frequency-range: 30kHz-96kHz
• Vertical frequency-range: 50Hz-160Hz


Samsung SyncMaster 997MB [silver bezel]

Note that the Samsung is favored for its good-looking, utilitarian bezel (the one I bought has a silver bezel). I thought the Compaq had a simple bezel, but on closer inspection, I see there's a slight curved contour to the top and bottom.

Does anyone know, with these indicated specs, if they're likely to work with the ScanJuggler XAGA Lite [see ScanJuggler XAGA Lite's specs here.]?

[studio460]

Well, good news! I messaged the eBay seller I bought the A1200 from and asked which monitor he used—it's a Samsung Syncmaster 796MB, and he said that it's, "the most optimal screen for the scandoubler."

Samsung Syncmaster 796MB 17" flat-screen 4:3 analog-RGB CRT:
Horizontal frequency-range: 30-85 kHz
Vertical frequency-range: 50-160 Hz

So that's within the specs of the above monitors, so both of the above should work well.

[jPV]

All scandoublers for Amiga double the Amiga's native 15kHz to 30kHz, that's why they are called as scandoublers, so "Horizontal frequency": check!

Amigas' vertical frequency is 50Hz (PAL) or 60Hz (NTSC), so "Vertical frequency": check!

All these three monitors should work with a scandoubler, which ScanJuggler is, for both PAL and NTSC modes.