Found a scan doubler ( who would like one ) ?

[kvasir]

oh, hell yeah! Though I've tried to e-mail this guy a few months ago, to no avail. Must have gotten the address wrong. Is there some sort of mailing list you could run on this, or just tick on the notify in this thread? (I've already smoked 2 1950 monitors, am now using my brothers old 1942 which is making a scary capacitor whine and jumps around a bit, making me think its on its last legs, and really DON'T want to dig up an old tv set, requiring me to not use my 800x600 resolution screen, and hope it can stabilize PAL games and play them missing the bottom of the screen)

[kvasir]

I'll have to ask my brother if I can do that. Meanwhile, I've gotten ahold of a second A1200, that has some sort of scandoubler in it, so I'm using a Mitsubishi Diamond Pro 91TXM 20" VGA monitor. Though I had to trade my super72 800x600 res for a PAL hires laced 724x566 screen. (Even with MonED and MIprefs I couldn't stabalize an image that size) Would still like to have an external scandoubler, though. This way I could still record AVI/MPG clips to VHS, and still use my nice 20" monitor doing it! (My older 1200 is set up with the old 1942, using an NTSC res, pretty much for recording animations to tape.)

[kvasir]

OK, I've finally gotten ahold of one of these things, arrived earlier this week and I've been playing with it a bit. It does get the scanrate to where my Mitsubishi Diamond Pro 91TXM monitor can display Amiga output, however there is a green tint too it. I believe this was touched on earlier in the thread, and I wanted to get other ppls opinion of whats going on with it. Apparently, the 16 bit input expected from the chip is split up between 3 channels as Red: 5, Green: 6, Blue: 5, Where AGA exports 24 bit signal as Red: 8, Green: 8, Blue: 8. I would think this would cause a drop in green tint, and overpowering of blue and red, but I guess my thinking was backwards here. The gentleman making these things seems eager to get an Amiga compatable version working, and was thinking of somehow dropping the extra green bit before it reaches the chip. (I think, I'm not too good at this level of digital electronics) My solution was to solder together 2 vga connectors with a resistor on the green line to bring it down to the same level as the red and blue, and being too lazy to work out the math, was actually going to solder 3 different variable resistors on the RGB lines and adjust the VGA display until it matched what was on my TV through the composite port, then measure the resistance accross the green pot and E-mail him the value for future units. I've uploaded 2 pictures here, of a test pattern (apparently from sweden, just something I grabbed off google images by typing "color test pattern" :-D ) and will edit this post or just add another one when/if they're approved. 1 is of the NTSC tv displaing the test image, and the other is the monitor displaying the same image. Any corrections in what I think is going on here would be appreciated, as I'm so good at hardware engineering that I currently hold a telemarketing job trying to sell cable telephone to people that don't want it. :-D

[kvasir]

OK, looks like the 2 pics I uploaded got approved.
This is the image on my TV set from the comp. output

And this is the green tinted scandoubled output on my VGA monitor.

I should mention while the "waiting list" on these seems pretty reasonable, he's reluctant to sell to any A1200/ A600 owners until everything gets hammered out. (I plan on testing this out on an old A1000 I have access to @ the end of the month)

[kvasir]

Still swapping E-mails with this guy, he's currently looking for an Amiga 1200, and was wondering if anybody in SW Virginia would be willing to sell or at least let him use one to get this thing working?

[kvasir]

OK, finally managed to dig up enough free time to get this post out here, Got a new unit from Roy about a week ago, and he changed the resistors on the input end of it for the 1200, which has fixed the green "tint" problem to a minimum, though there still is a slight bit of discoloration noticable when the overall pallete is darker. A bit muddy on interlaced screens, too. That said, it works very well for most games I've tested. (One of the reasons for my lack of free time time is the fact I couldn't run half my games due to needing dblntsc and multiscan compatability for my monitor, and was going through withdrawl :-D ) It does result in some color drop due to 24-16 bit conversion, and as such would be ideal for an Amiga 1000, 500, 2000, 600, and 3000 if it didn't already have a scandoubler. AGA does do 24-bit, and results in the color loss, but this isn't terribly noticable. Its best to keep the unit in PAL mode, as he uses a jumper to switch between the Pal/Ntsc, and PAL in NTSC will result in the familiar cropping of the bottom of the screen. NTSC when the scandoubler is in PAL doesn't have any noticable problems, however. Only other thing for 1200 users to consider is if you use the composite out rca next to the rgb port, the 23 pin adapter he uses overlaps it to where it can't be used, unless you cut the screw tab off of that side. (One reason I wanted an external scandoubler is so I can use my 20" VGA monitor while still sending output to my VCR.) So far, I've moved all the scandoubled screenmodes into my sys:storage/monitors and stuck with NTSC/PAL in devs:monitors, saving lots of memory there. For what he's charging for these things, its a pretty good deal!