Re: PET Graphic, Font, 40/80, Composite and Audio Boards

Den Sat, 24 Mar 2018 00:21:39 +0000 (UTC) skrev Steve Gray
<sjgray@rogers.com>:
> No, the 8296 (and D) use exactly the same character rom. The 4000 and
> 8000 series machines can also do this 10-pixel tall character height
> thing. On all these PETs there is a little circuit that ensures that
> only the first 8 pixels are displayed and that the 2 extra lines (or
> more) are blank. Steve

Oh, so does this mean that the monitor is a multi sync (15 and 18 kHz),
or is the 350 line information about the B series monitor incorrect?

Or is it rather that (especially US versions) the low profile with
external monitor versions of the B series uses fixed frequencies for
both vertical and horisontal, and thus can't have more than 8 scan
lines per character row, but the high profile buildt in monitor
versions can use 50Hz even in "NTSC land"?

>       From: Mia Magnusson <mia@plea.se>
>  To: cbm-hackers@musoftware.de 
>  Sent: Friday, March 23, 2018 8:16 PM
>  Subject: Re: PET Graphic, Font, 40/80, Composite and Audio Boards
>    
> Den Fri, 23 Mar 2018 07:26:04 -0700 (MST) skrev vossi
> <vossi@ceffy.de>:
> > I just checked my monitors. Before this I noticed only the light and
> > dark green tubes!
> > 
> > You are right - the 8296D and the 7xx have the same monitor pcb (and
> > the darkgreen tube).
> > The 8096sk and the 8032sk have a different pcb and the light green
> > tube. It's possible that the older monitor is not capable to display
> > the 350 lines
> > - I never tried it.
> > 
> > PS: with the hsg board installed I had to tune the picture-height in
> > the sk to see the whole screen. On the 1702 external connected I
> > have exactly a full screen pic with the hsg.
> 
> My 8296 (not D) uses 8 pixels high characters for upper case /
> "graphics character" mode, and switches to insert some blank lines
> between each character in lower case mode.
> 
> With 2 blank lines between each character row which itself is 8 video
> lines, you get 25 rows of 10 video lines each, minus that you don't
> need to show the two blank lines outside visible text, giving 248
> lines displayed on screen. With rather large borders it might be
> possible to display 350 lines in that mode.
> 
> P.S. this must mean that 8296 has another ROM than the 8096 and 8032,
> right?
> 
> I were so sure that all PETs used 15kHz monitors, and not the 18kHz
> MDA/Hercules monitors. But my 8296 is suspiciously silent compared to
> most 15kHz monitors, even smaller black and white, which usually
> screams really annoyning at 15kHz.
> 



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