C= A3000T no video from db15

[alexh]

It has to be in NTSC mode to produce a picture on most LCD monitors

[alexh]

Alexh: NTSC is only for native modes iirc, which I am getting output to my 1084S.

It's not a separate RTG graphics card it is a native mode scandoubler. The output is just a scandoubled version of what you're getting on the 23-pin (1084s).

Whatever mode you're in (PAL/NTSC) is what you get on the 15-pin output but with a Horizontal refresh of 31KHz rather than 15KHz.

If you are in a PAL mode the vertical refresh rate will be 50Hz, which is outside the capabilities of most modern monitors. You need to switch to NTSC to get 60Hz before most LCD monitors will work.

I bet money there is nothing wrong with your AMBER chip.

[alexh]

I have seen LOTS of LCD monitors which will not sync down to 31Khz properly.

Strange. I've never seen this. I thought every monitor was rated to 31KHz?

I've seen something similar with the software DBL_PAL and DLB_NTSC screen modes (even with CRT) and you can improve it using the VGA monitor driver but I've never seen it with a hardware scandoubler in NTSC mode (60Hz).

trying to source a TFT that will. Although that is becoming harder by the day!!

?? All LCD's are TFT aren't they?

[alexh]

Interesting...

For me it has always been the other frequency... the vertical. Most LCD panels are rated to 56Hz vertical and so don't sync to PAL refresh rates.

[alexh]

If you're not fond of changing the jumper you can use the early startup screen to switch temporarily (hold both mouse buttons before powering up, wait for a bit and then hit the space bar).

FYI : This is a Kickstart 3.x feature