Re: Trackstar video problem.

[pausch@saaf.se (Paul Schlyter)]

In article <20040531004235.19841.00000269@mb-m02.aol.com>,
Michael J. Mahon <mjmahon@aol.com> wrote:
> Frank Townsend wrote:
> 
>> Has anyone gotten an Apple composite monitor to work with a Trackstar?  If
>> so, which one?
> 
> The Trackstar video output is the same as the Apple II composite video
> output (the RCA connector).
> 
>> I don't want to install the modification listed in the FAQ, and I don't know
>> where to find a CGA monitor.
> 
> Any monochrome or color NTSC (not PAL) TV monitor will work.
 
Monochrome monitors which are NTSC or PAL don't exist, since NTSC and
PAL are different ways of encoding color information; since
monochrome monitors don't need that information, they don't have any
NTSC, PAL or SECAM circuits at all....
 
Regarding 625-line vs 525-line monochrome monitors and TV's: you should
be able to use either of those.  I have myself used a monochrome TV and
two different monochrome monitors -- presumably they're all 625-line
since they were bought here in Sweden.  But they all work well also on
525-line TV signals; all you need to do is to adjust the vertical sync
a bit (the horizontal sync frequency is so similar that it doesn't need
readjustment).
 
And how do I know this?  First, my TV set can be used to receive TV
transmissions over the air (which are 625-line transmissions of
course), and it works as expected.
 
Second, my old XT clone (which still works; the harddisk has died but
if I run it on floppies only it works fine) has a CGA graphics card
which also produces NTSC composite video; the NTSC color info is of
course ignored by the monochone TV set and the monochome monitors,
but the remainder of the signal is 525-line format and both the TV
and the two monitors can be made to sync to that by only readjusting
the vertical sync.
 
Third, my good ol' Apple II+ (which never had any harddisk) has a
hardware jumper on the motherboard with which you can switch the
video output from 525-line 60 images/sec to 625-line 50 images/sec.
At first it was configured for 625-line, but later I removed the
jumper, making it produce a 525-line video signal.  Both the TV set
(through an RF modulator) and the two monitors could be made to sunc
to both types of video signal format, merely by readjusting the
horizontal sync on the TV or monitor.  And as an added benefit, I
could use slot 7 for any Apple II card; before removing the jumper
(and also removing two wires) it was reserved for the "PAL color
card".... trying to insert any other kind of Apple II card there
could cause hardware damage.
 
Another reason to switch my Apple II motherboard to produce 525-line
video was that for some years I let that XT clone and the Apple II
share monitor: by making the two computers produce the same kind of
video signal, I didn't need to readjust the sync of the monitor when
switching the monitor between the computers.
 
 
Now, what about using a PAL color TV or monitor on an NTSC video
signal?  Well, it ought to work, although you won't see any color
but just a B&W image.
 
> If you like, you can use a modulator and a TV set, as long as
> 40-column text is enough.
> 
> They are readily available used, and often are considered junk.
> 
>> (CGA to VGA converters are prohibitively expensive.)
> 
> ...and less than perfect, as well.
> 
> -michael
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