exxos's Atari, Amiga & retro forum

Hello!

Im wondering how you enable the MONO resolution on a H4 ? I have seen the jumper and tried switching them but when i do the screen is all black.

/zChris

Firstly does your monitor support high resolution ?

Yeah, at least other ataris have worked on it in mono mode with ube switch.

zChris wrote: 17 Jan 2022 06:17 Yeah, atleast other ataris have worked on it in mono mode with ube switch.

Have you tried the UBESwitch with the H4?

I think I known what the problem is..

https://www.exxosforum.co.uk/forum/viewt ... =50#p30655

The jumper on the H4 only enables the MUX to output mono, it doesn't switch the video to mono. If you plugged in a mono monitor then that would switch the video to mono. Currently you are telling the MUX to use mono, but the shifter is still outputting colour, so you get a black screen.

On later boards it was fixed that plugging in a mono monitor would automatically switch the MUX as well. But on the H4 you have to switch the MUX AND switch mono on pin, on the monitor port to switch the video to mono mode.

There was a proposed fix using an inverter but nobody came forward to test the idea out.

What exactly does the mono monitor do in order for it to switch over to mono? Ground the Mono pin?

/zChris

zChris wrote: 18 Jan 2022 17:27 Ground the Mono pin?

Yep.

So when i have the jumper on MONO and ground the MONO pin i should get into mono?

zChris wrote: 19 Jan 2022 07:01 So when i have the jumper on MONO and ground the MONO pin i should get into mono?

Yes.

Alright. Is getting MONO the same as high res? Maybe i have mixed that up. Anyway when i ground the mono pin and jumper the MUX i get a blank screen. Is there something else thats needs to be done in order to get MONO / high res ? Atm there is a VGA connector soldered on.