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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: RMK305 on February 13, 2008, 10:01:42 PM

Title: General scan doubler question.
Post by: RMK305 on February 13, 2008, 10:01:42 PM

I'm planning to get a scan doubler and a  switcher box to use with the CV64 3D. I've found a Mikronic scandy internal unit for £45 which seems reasonable. However, I've read a review that states that this card shifts the image to the right of the screen and the reviewer stated he had to use the monitors controls to correct this. Do all scan doublers suffer from things like this? I'd rather not have to adjust the monitor everytime it switches from GFX card to scan doubled output.

Thanks.

Title: Re: General scan doubler question.
Post by: alexh on February 13, 2008, 10:42:40 PM

Most monitors (with digital controls) have settings per resolution.

Scandoubled image will probably be detected as 640x480.
CV64 3D will be 800x600 or higher.

Your monitor SHOULD remember the settings for each.

Dont forget your monitor will need to support 50Hz vertical refresh rate to use a scandoubler(which rules out most LCD monitors).

Title: Re: General scan doubler question.
Post by: RMK305 on February 13, 2008, 11:21:57 PM

It's an old style crt monitor. I'll maybe just go for the scandy and see how it goes. I'll just sell it on if it doesn't work how I want it to.

Title: Re: General scan doubler question.
Post by: Bonami on February 14, 2008, 04:43:49 AM

Hi,
I recently got myself a used A4000, shipped all the way from UK to where i am - the tropical fareast. (Thank God the 1.7gb harddisk survived the long distance!)

To my delight the 15 year-old machine came with an internal DCE SD/FF, which i plug to a Samsung 940B (http://www.overclockersonline.net/index.php?page=articles&num=311&pnum=2)

Well, with just the plain vanilla OS3.0 installed, there's nothing to shout about the display. But the fact's it works - except some demo which showed garbled moving images (probably those demos meant for OCS or ECS?).

So, my question is, why my A4000 with DCE sd/ff works OK with my Samsung 940B which, as the specs go, has 56-75hz vertical freq?

Does the DCE output strictly 50hz of vertical freq? Is the spec info (as link above) incorrect?

Btw, i take this opportunity to put out a question, can i use multiscan/ productivity mode with the DCE sd/ff? I tried but failed, but i was not sure what was wrong... (the A4000 has ROM v3.0 & WB3.0)

Kindly share with your knowledge & experience. Thanks.
Regards, Bonami.

Title: Re: General scan doubler question.
Post by: countzero on February 14, 2008, 04:56:41 AM

Quote

Bonami wrote:
Does the DCE output strictly 50hz of vertical freq? Is the spec info (as link above) incorrect?

No. It just doubles hor. frequency. Vertical is left untouched. If you're using a PAL mode, it's left at 50Hz. If NTSC, 60 Hz. You were either using an NTSC mode or your monitor can handle 50 Hz. I have an Eizo LCD which specs say  only work till 56 Hz, but it does handle 50 Hz perfectly, though displaying an annoying OSD message.

Quote

Btw, i take this opportunity to put out a question, can i use multiscan/ productivity mode with the DCE sd/ff?

no. It's not necessary anyway. multiscan productivity mode must be compatible with most LCD/CRT monitors out there. I can use it perfectly fine on my LCD.

Title: Re: General scan doubler question.
Post by: rkauer on February 14, 2008, 05:02:47 AM

 Minor correcting: yes, it will work. But you'll have a major slowdown (and it is not a military patent) in graphics's refresh.

 So why use it, anyway? Just to get 640x480? There are many more high screen pixels in 15kHz modes.

Title: Re: General scan doubler question.
Post by: Bonami on February 14, 2008, 06:49:30 AM

@ Countzero,
Thanks for the info in your reply.
If i want to use multiscan or productivity mode in my A4000 already equipped w/ DCE sd/ff, do i use the VGA adapter that plugs to the original video port? ie i have to switch between two display/ monitors?

@ rkauer
Thanks. When you say "yes it will work" do you mean that scandoubler can output the multiscan/ productivity mode? If so, could you kindly share how?
(i tried by moving the multiscan, productivity, & VGAonly to the device drawer, and change the screenmode via Prefs, but the display blank out, or the system hung, sorry i can't remember exactly)

Thanks & cheers!

Title: Re: General scan doubler question.
Post by: countzero on February 14, 2008, 06:53:16 AM

yes, you have to use the original RGB port (switch monitors, or get a monitor switcher)

problem is, scandoubler tries to double already doubled multiscan modes, which produce an unsupported frequency for most monitors (well at least mine couldn't handle it).

Title: Re: General scan doubler question.
Post by: Damion on February 14, 2008, 06:53:37 AM

My recollection is that the DCE unit will "pass through" non-15kHz modes like Multiscan... but like rkauer says, they are sloooooow! ;-)

-edit-

@countzero -- that's weird, I'm pretty sure mine left them alone??