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PAL card: I think I've got it but...
- Subject: PAL card: I think I've got it but...
- From: Linards Ticmanis <ticmanis@coli.uni-sb.de>
- Date: Sat, 16 Feb 2002 05:18:46 +0100
- Newsgroups: comp.sys.apple2
- Organization: University of Saarland, Computing Center, Germany.
- User-agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:0.9.8) Gecko/20020204
- Xref: archiver1.google.com comp.sys.apple2:17577
...I'm not sure. The card I have seems to demand a signal VIDEO to be
present on Slot 7 Pin 28, TEXT on pin 23 and 14M on pin 24. (Thanks
again to P. Schaefer for the schematic!!)
Well, I know the Europlus has something on pins 23 and 24 (unused in the
NTSC II+, right ends of the DMA and IRQ daisy chains). However I've
never heard that it has anything special on pin 28 (daisy chain DMA from
slot 7 to slot 6 in the NTSC II+). This could be a clone specific thing,
right? I know the card is not made by Apple and it was used in some sort
of clone before.
Questions:
1.) Are Pin 23 and 24 indeed TEXT and 14M? I assume the answer is YES.
2.) Is pin 28 indeed VIDEO? I assume NO.
This would explain why the card shows an extremely low contrast picture,
barely visible within the "snow" you get when you turn monitor
brightness to maximum: It's providing everything correctly, especially
SYNC and color burst, except for the video signal proper, which is just
"caught" through RFI in minute amounts.
There seems to be a place provided on the card to connect a wire to this
same line, however where do I find a TTL level video signal on the
board? I assume it's at the lower end of the 1.5K resistor which is the
rightmost of the three that are to the right of the game connector - R7
according to the Red Book, page 151, right?
Or can I just connect the "wire wrap pin" although it's not TTL?
(Now for the fun part: All of this didn't occur to me until after I had
already unsoldered and replaced half of the components on this PAL
card... Don't you hate it when that happens?)
Thanks again for your help,
--
Linards Ticmanis
The Master said, "The business of laying on the colors follows the
preparation of the plain ground."