Video Overlay Card questions...

[a_specto@alcor.concordia.ca (Mitchell Spector)]

    A few weeks ago I acquired an Apple II Video Overlay Card (one
lacking the composite video in/out connector, though I managed to
construct a suitable replacement) and installed it in my Apple IIgs.
The card appears to be in working condition though I've come across 
a few oddities I'd like to share...

- First off, anything plugged into the VOC (RGB display, television,
VCR) has vertical lines or banding running through the picture. I
don't mean solid visible lines, just an extremely fine and *subtle*
pattern going across the screen, like bars. You can mostly notice it
on a black screen when you increase the screen brightness to
maximum. Most people probably wouldn't notice it at all, but I do. I
have seen this effect on older VGA cards, namely those made by 
Cirrus Logic, so perhaps it's more a "feature" than defect? 

- When I output to a composite display, Super-Hi-Res graphic images do
improve in the sense of less color bleeding and colors looking as they
should, but everything is rather blurry through the VOC. It also seems
to have less color saturation than what's displayed through the
built-in composite video port on the IIgs. Is there a focus control
pot on the card to correct this? Follow the URL below and scroll the
the very bottom of the page to see example screen shots (two 8K
JPEG's) comparing the standard video-output from the IIgs and from my
particular VOC...

http://forums.delphi.com/n/mb/message.asp?webtag=apple2&msg=3383.1

- When I genlock a live video signal and display it on the IIgs RGB
monitor (say the Finder desktop with a TV signal in the background) it
appears as if Super-Hi-Res graphics are put into interlace mode. Or at
least the image is somewhat flickerly and less stable. Is this normal?
I believe NTSC television broadcasts are interlaced by nature so this
would appear to make sense.

- The VideoMix NDA allows you to adjust the tint and color saturation
of any incoming composite video signal (such as a TV, VCR, camcorder).
It looks as though those settings are stored in NVRAM on the card, or
at least in the GS's battery RAM. I kind of mucked it up and want to
reset it to the default. How can you do this?

- When running the 'Apple II Video Overlay Card Diagnostic v1.0',
under RAM/Register Tests the diagnostic routine called "RAM Test (IIgs
only)" fails with the card plugged into my ROM 3 board with all slots
filled. However, running the test with the VOC plugged into a
bare-bones ROM 01 board passes. What exactly does this routine test?

- Finally, I'd like to know what software exists for the VOC that I
may have missed. So far I've come across the following: 

   - System 6.0.1 (VideoMix NDA/Tool033/VOC INIT) 
   - Apple's Video Overlay Card Diagnostics 
   - Todd W's VOC interlace slide-show demo 
   - SuperConvert 

    Is there anything else? I vagely remember something called
"VOC.TV" which blanks the RGB screen so it can be used as a 
composite video display of sorts, but I've had no luck finding it (can
anyone here help?). I also recall HyperStudio having some basic 
VOC support but I don't quite recall what exactly. 

    For the moment I'm mostly interested in learning what the 10 pots
on the card control, which are labeled as:  R1, R2, R3, C2, C13, C15,
C18, C20, C24, C25. With the exception of two near the back, all seem
to be factory preset and covered with a drop of paint or wax. If one
of these control _focus_ (I recall hearing there was such a control)
I'd like to know which one. I'd be grateful to hear from any other VOC
owners out there or anyone technically familiar with the card.

ps - Perhaps I should reintroduce myself. I was a regular of
comp.sys.apple2 throughout most of the last decade (1991 until about
1999) though disappeared and retreated to Delphi's Apple II forum
after noise levels here became impossible to ignore. However, with
Delphi on the verge of death (if not already dead) as far as an Apple
II related service, I'd like to find an alternative once again. If
things have quieted down here I'd reconsider comp.sys.apple2 again,
though I'd only visit and participate on an intermittent basis at this
point. Of course it wouldn't take much to drive me away once more so 
I don't want to make any promises.

Mitchell Spector
a_specto@alcor.concordia.ca