The Sinclair QL Forum

Doing the calculations, the crystal in US QLs should give you four of those "sweet spots" per line. You can see 3. the fourth being off the screen. The 15.36 should give something like 16.

It didn't seem to change anything. BTW looking at the plans for the QL, it has what I believe is the main crystal as 15 MHz. Is this accurate. The crystals on mine seem to be different. The main crystal being 15.10489 MHz. So the VGA issue was still there after you removed the board? Yes, the probl...

I am reasonably handy with a soldering iron. I'll try that. What does the 74HC mod do? Well, I've yet to meet somebody who knows, nobody has ever documented it. If it is what I think it is (again, I only know the one grainy photo) it's technically redundant, like Bwinkel my guess would be that it w...

Do you have a soldering iron and are you adventurous enough to disconnect the upper two wires from the QL board? Should be easy enough to re-attach after the fact. The lower wires are just for power as far as I can see and can stay. The upper wires are directly connected to the crystal, so it does ...

Sorry opening up the machine, there is definitely a daughter board in place.

I'm still not sure what to make of it. QL-VGA v2 can handle pixel clocks from 9.976 to 10.024 MHz, so even if the crystal is way off it should cope. But then in your example picture we see that the lines are complete, which I think means that the correct clock is detected. It looks more like a freq...

mk79 wrote:Is the picture static or does it change over time?

The distorted sections of the screen (at least at their edges) shimmer between adjacent pixel values. It is very much like the pixels go in and out of sync a few times for every scan line.

The distorted sections of the screen (at least at their edges) shimmer between adjacent pixel values. It is very much like the pixels go in and out of sync a few times for every scan line.

Well, good news and bad news on my QL-VGA (v2) issues. I got a new ZX8301 and a ROM switcher. So, my QL works again. Yay!! Unfortunaely Using either Minerva or the JS (instead of the JSU) ROM. I have the same timing issue corrupting the display. Obviously there is something odd about the timing on m...

Yeah, I guess the QL-VGA "screen-saver" is displayed well when the QL is switched off, this is not a monitor issue. Amazingly little details are known about how exactly NTSC QLs really work, and I don't have one either, so QL-VGA probably cannot handle them as-is. But when you switch to a...