mikeh_nz wrote: ↑Sun Feb 05, 2023 4:05 am
- Should I leave my zx81 without R30 and at UK 50Hz. That is, is it better to have more resolution with scan lines and instead use a solution like rgb2hdmi with an analog front end to render the screen in hdmi?
Only you can decide. Obviously the vast majority of ZX81s in Europe run their video at 50Hz. Hence most games are designed for this. That does not always mean that they will not work okay on 60Hz video. It’s not something that I’ve tried much.
As I have TVs that work with my ZX81, I’ve never actually tried using a composite (or RGB) to HDMI converter with one. Note that if using a RGB type, all three channels plus the sync input need to be connected together. That
may be enough to get it to work. Otherwise the sync signal needs separating from the composite video from the ZX81.
I did once try a very cheap composite to HDMI converter with another computer, but the quality was poor.
mikeh_nz wrote: ↑Sun Feb 05, 2023 4:05 am
- If I leave it at UK 50Hz, can I get it to display on my USA Tv?
Ahh, that depends. Are you feeling lucky?
In Europe, a lot of modern (as in LCD) TVs use chips and circuitry that is actually multi-standard compatible, hence can display a 525 line 50Hz NTSC video picture.
But as the U.S.A. is such a big market all on its own, it’s worthwhile producing TVs that are only compatible with the video standards in the U.S.A.
However, despite this, it has been found that some will actually display a 625 line 50Hz picture without problems, even though there is no mention of this in the specification, instructions or manual.
There will also likely be some where the capability to display a 625 line 50Hz picture was included in the specification, instructions or manual.
Hence, the only way to know, if it’s not already stated, is to try. You cannot harm a LCD display by feeding it a ‘wrong’ video standard signal. And the original reason for the vertical frequency being the same as the mains frequency is no longer relevant.
Also, if you want, you could use a switch. You only need a simple SPST type.
Mark