C=1940 800x600?

[trixster]

I think the C=1942 (and the 1940) can handle 800x600 resolution but does anyone know what the maximum refresh rate is at this resolution? I tried 60hz (running from an rtg card, not a native screenmode) and I got a garbled picture.

In picasso96mode I made sure 800x600 was set up in accordance with the vesa spec for 800x600, so I can only assume the monitor is struggling with the requested refresh rate?

[Thomas Richter]

The critical part may not be the resolution itself, but the size of the sync pulses. You can try to enlarge them somewhat and see whether this helps. Also try to alter the polarity of the sync pulses.

[trixster]

I’ll try that, thanks. I did wonder about sync. Might 800x600 require a different sync polarity to 640x480?

[Jope]

I seem to remember my 1942 couldn't quite get to 60Hz at 800x600. It was something like 54 or 56.. Try starting from 50Hz and work your way up.

I seem to remember it did manage it and I didn't have to use interlace. It has been over 20 years now though.

Sync polarity shouldn't matter.

[trixster]

Thanks Jope, I’ll try that

[fgh]

A french guy named Marc Guthmuller wrote about modding the super72 mode to match 1942 specs back in 1994:
(Google found several reports of terrible flicker in 800x600 but according to this article that's due to super72 using 23kHz, which is in between the monitor's two supported frequency bands)

https://obligement-free-fr.translate..._x_tr_pto=wapp

[Kin Hell]

@ Trixster

Page 7 of the manual bud....

https://bigbookofamigahardware.com/b...9401942man.lha

At least you'll know how far to push. - Good luck not popping something. (re-capped?)

[trixster]

Thanks pal. I had a look in the manual and saw the specs including max refresh rate of 75hz, but it won’t get even close to this at 800x600. Sadly it doesn’t give you the rate for each resolution, rather it states generically what the monitor is capable of.

[Kin Hell]

Originally Posted by trixster

Thanks pal. I had a look in the manual and saw the specs including max refresh rate of 75hz, but it won’t get even close to this at 800x600. Sadly it doesn’t give you the rate for each resolution, rather it states generically what the monitor is capable of.

What can u get @ 800 x 600? - Knowing your verticals will help.

& it's been a while, but iirc, there were specific Drivers for the C= 1940/42 Monitors. - Are you on those? - Do they have info on Resolutions via Icon Information?

[trixster]

Monitor Drivers are only useful if I’m using the aga chipset to drive the monitor but I’m using a graphics card. So I’m dialing the details into Picasso96mode directly.

[trixster]

I think Jope has got the right idea with 54 or 56hz. I need to just get round to trying those when I’ve got a spare moment!

[robinsonb5]

Maybe these timings will help?
http://tinyvga.com/vga-timing/800x600@56Hz