Re: Apple GS RGB monitor question, are the leads reversible that connect from the GS to monitor?

[supertimer@aol.com (Supertimer)]

gospodin@clubi.ie (Vincent Quinn) wrote:

>supertimer@aol.com (Supertimer) wrote:
>
>>Also, if you have a friend who is a qualified technician
>>with experience about monitors/televisions, it is possible
>>to actually change the sync of a Macintosh monitor,
>>running it down to 15Khz and have it work on the IIGS.
>>
>>This is only worthwhile if your friend would do it for
>>free, though, and even then some might consider it
>>ruining a Mac monitor.  Still, it is nice to know it can
>>be done.
>
>_How How How_? I'm not a qualified technician but I'm getting very used to
>messing around inside monitors _and_ I have a Mac RGB monitor sitting right
>here...

I do not know the exact details, but Jim Poore, who
used to answer technical questions here on csa2, has
done the mod before.  He basically goes in and
changes several components which regulate the sync.
The result is that the Mac monitor's new sync is 15Khz.

>Can it also be done with a VGA monitor?

Yup.  Mac monitors and VGA monitors are the same,
both analog RGB.  It is just the connectors that are
different.

>And (although comp.sys.amiga is probably the place to ask this, but here
>goes) what exactly is the ScanDoubler that can be used with an Amiga and a
>VGA monitor (duh, a device that takes the Amiga 15KHz sync video output and
>doubles it to 30KHz to drive the VGA, right?) Is it a card or an external
>box/ Does anyone know whether one could be used to enable a VGA monitor on
>a GS?

Sadly, all the Scan Doublers for the Amiga are internal
cards.  The principle is sound and if an external device
existed for the Amiga, you could plug it right into the
IIGS.

There was a discussion here several months ago
about what it would take to build a similar device for the
IIGS.  Apparently, it would have to buffer the scan
lines and resend each one twice.  Some of the timing
signals are available from the motherboard but not
from the IIGS video connector.  This is probably
the reason why Amiga Scan Doublers themselves
are slot cards.