50hz slow, 60hz even slower.
Hard to tell the difference display wise on my monitor. I thought the K looked a bit lower and the screen maybe a bit greyer?? But I couldn't tell.
So to see if my switch was working, I decided to run a speed test.
I found a basic program on this forum talking about 50hz and 60hz Zeddiesto be used for a speed test, so I typed it an and tested.
(Glad I could flip the switch without power cycling and re-typing. It was only like a 6 line program, but still. )
With the switch one way, it completed in 19.73 seconds.
(Well, not completed, as I stopped it when I saw the first result number display on the screen, but it still works for the test.)
With the switch the other way, it completed in 30.06 seconds. (Well, again I stopped it when the first result showed up.)
So, I am guessing the first switch direction is 50hz and it is about (at least for that test) a third faster than the 60hz test.
Wow. That is significant!
(Which makes me wonder if I will ever use it in 60hz mode. Perhaps there is a game that I need to slow down a bit? )
And it looks like my switch worked! Yay!
Sinclair's BASIC ROM reads the 50/60 position, to create the right picture.
But some software made in machine language might not read the position and hardcode/assume 50 or 60.
ZX81, Lambda 8300, Commodore 64, Mac G4 Cube
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Yes, the Sinclair ROM code reads the 50/60Hz pin every time it generates a TV line. So if a switch is connected to this pin, you can switch between 50Hz and 60Hz on the fly when using BASIC.
Thinking this might be the case for me with swaotch basic hi-res graphics demos... not sure.