Thanks for your answer. I have found NTSC video to PAL video or PAL-RF
converters for Playstations, for less than $10each. Unfortunatelly, they do
not support RF input, but only Composite input. I am not sure, but I suspect
that I might be able to hack the PS/PS2 connector and replace it with a
standard female RCA connector, and use it as the NTSC input port.
I had found quite a long time ago, a generic device, that was used for the
conversions, for far less than E100 (~$100), but I had no need for it at
the time.
My problem is that I have some micros, like the Ti99/4a or Commodore MAX,
that use NTSC only standard output and I have is RF. Using a custom cable, I
could bypass the Ti99/4a modulator, and use the composite video (in NTSC
format) as the modulator is an external device.
But for the USA version of the ZX80, I need to hack the motherboard, to get
the video signal, unmodulated. And I do not want to alter or modify a
"museum" item.
I also do not want to use 3 different TV sets. It's very silly to do so. I
have a SONY VCR that can playback NTSC video tapes, but it's not capable of
translating the NTSC to PAL, and output it on PAL TVs.
I know that there is professional equipment, and it's very complicated to
convert the SECAM to PAL, as well as the NTSC to PAL. But I recall a small
do-it-yourself kit (From Vellerman?) many many years ago that was supporting
this function costing only a few Euros.
What you are in need of is a video standards converter, and these are
usually found under broadcast equipment. Input composite video is
decoded into its constituent parts (luminance and either chrominance or
component information), stored digitally, and regenerated with the
encoding needed.
PAL is an enhanced but incompatible version of NTSC, and SECAM is a
wholy different encoding system, and I don't have the time or space to
go into detail here. I do know of multistandard VCRs that will play
back different system's tapes; whether that would work as a standards
converter is unknown. For what you are seeking, you are looking at a
substantial investment, probably far in excess of what a separate TV for
each system would cost.
Also, as you've found out, the horizontal and vertical scan rates vary.
I do know that a black and white NTSC monitor will after a fashion
display PAL video, albeit without color.
My Amigas are set up for either 525/60 or 625/50 scan outputs, but they
are also RGB separate outputs, and the encoding method becomes a moot
point there.
I'd say just keep a television set that is multistandard, or have
separate NTSC/PAL/SECAM sets compatible with the computers you have, and
the RF frequencies each needs. One television set that does it all is
probably available, but more costly than the previous solution.
Gary Hildebrand
St. Joseph, MO