The Sinclair QL Forum

Hi,
Sinclair QL was never officially launched or imported to Argentina. It's a very rare computer to find here and I only know about a very few here and less of them working like mine. At that time relationship with UK was broken because of the war. We had our stron contact with Sinclair's products ...

Finally!!
I miss the line linking the GND at https://github.com/holmatic/video_if_ql_vga
I just added a small wire, there are several GND pins at the Pico that can be used.




Thanks to everyone that took a minute to read and answer helping me so much..

Connecting.png
OK, I followed exactly this wiring but using a DB9 as input as I usually use a DIN->Db9 adapter to my OLD CRT.
I 'll ad a wire Linking all three GND (all coming from different PSU, that scares me a little) and try again.
I don't have another pico at hand but I'll get one or two ...

The junction of all your 680ohm resistors don't appear to be at a ground (OV) pin on Pico. Either way you insert the Pico they appear to be connected to GP0 or GP16 ? Could we see underside of strip board to confirm the apparent wiring from the topside?


Hi, they are connected to the GND pin at ...

I come from.
https://theqlforum.com/viewtopic.php?p=50691#p50691
trying not to get in the way of that thread

I built my own board using a conventional Raspeberri PI pico, the long plate.
20230319_183224.jpg
and I got this kind of result,
GIF-230318_014332.gif
please click to see in motion

i ...

Output channel levels are about 4v.. isn't that too high vor a VGA?

If "output channel levels are about 4V" means RGB signals: Much too high. Did you forget the output resistors? Together with the termination resistors inside the monitor, they scale down the output voltage. Or did you measure ...

Hi all,
Mine is a UK, 50Hz ISS 7 QL.
I have a humble hanheld oscilloscope that I hope is good enough for this.
I measured the QL output at the cable adaptor end without the Pico connected..
Signals are TTL level.. perhaps a bit high?
I did ground the probe to the composite output with a perhaps ...

Well I reviewed all connections, cleaned up the board looking for any flux residue.. added the rgb gnd connections to the dsub15 output (my old CRT doesn't like any pins soldered together) then wrapped anything whith tape and then aluminum foil with a wire I soldered to the db15 metal case and to ...

You didn't even write which module you used.

I'm sorry about that... I used the conventional raspberry Pi Pico, the larger one, and downloaded the firmware from the github page

Are you aware that different binaries are needed for the (small) RP2040-Zero and the (larger) Raspberry?
Did you keep ...

Hi,
I've just finished my QL pico VGA using a strip board (it didn't look so difficult) I guess I have some Sync problems.
Screenshot_20230317_025359_Gallery.jpg
Image is not steady with some horizontal jumps and the rainy band moves from top to botom, then the "signal?" Screen apears briefly ...