PAL & NTSC Via Holding Down Mouse Buttons

[crazyegg]

Hi All,

I have a NTSC Amiga.

What exactly is outputed from the NTSC Amiga when I boot into PAL mode (by holding down both mouse buttons during bootup)?

I have read many forums and the general consensus is that (if using the above situation), the NTSC Amiga will output a 50Hz PAL scan rate but the colour system will still be NTSC (i.e. NTSC 50?) Is NTSC 50 even a standard?

If so, why on earth would Commodore do this? What were they thinking?

Ideally, the Amiga in question should be outputting a 50Hz PAL scan rate AND a PAL colour system (i.e. true PAL or PAL 50).

Am I missing something here??

Regards,
ed...

[meega]

Are you sure it stays in PAL? I think that boot-screen flip thing might just be for getting an image to start with. I'm sure my miggies would toggle the display by pressing the space bar, but flipped back to system default when actually booting. You might need the PAL monitor driver in DEVS:Monitors to get a proper display when Workbench loads.

PAL60 is a standard, no idea about NTSC50.

[Toni Wilen]

Originally Posted by crazyegg

Hi All,

I have a NTSC Amiga.

What exactly is outputed from the NTSC Amiga when I boot into PAL mode (by holding down both mouse buttons during bootup)?

I have read many forums and the general consensus is that (if using the above situation), the NTSC Amiga will output a 50Hz PAL scan rate but the colour system will still be NTSC (i.e. NTSC 50?) Is NTSC 50 even a standard?

50Hz + NTSC color encoding. NTSC50 and PAL60 are some kind of pseudo-standards..

If so, why on earth would Commodore do this? What were they thinking?

I guess cost was the only reason, NTSC/PAL color encoding needs different components and it would also require some switching components and extra (cia?) io output. (at that time)

Ideally, the Amiga in question should be outputting a 50Hz PAL scan rate AND a PAL colour system (i.e. true PAL or PAL 50).

Possibly. Use RGB connection and there is no need for PAL or NTSC color encoding (yes, I know it wasn't really available in non-euro countries)

[stefcep2]

Not sure if its 50 hz NTSc that is outputed as there is definately less flicker ie higher refresh frequency and less scan lines when booting in NTSC mode on a PAL A1200. And games run faster, with less flicker. My eyes are particulalrly sensitive to refresh flicker, so I have always preferred NTSC screen modes, even if I have less screen real estate.

[Toni Wilen]

OP was talking about color encoding, not refresh rates. Refresh rate does change, color encoding does not (color signal get comes from composite or RF out. RGB out have... RGB color encoding )

PAL Amiga in NTSC mode still outputs PAL encoded color signal ("PAL60").

NTSC Amiga in PAL mode still outputs NTSC encoded color signal ("NTSC50")

[crazyegg]

Hi All,

Thanks for all the replys.

As Toni pointed out:

- PAL Amiga in NTSC mode still outputs PAL encoded color signal ("PAL60").

- NTSC Amiga in PAL mode still outputs NTSC encoded color signal ("NTSC50").

Are there any TV's that can support NTSC50 mode? I have tried several multisystem TVs on my NTSC Amiga (booted into PAL mode) and the resulting picture (while correctly scanning at 50Hz) is black and white (i.e. outputting in NTSC colour signal).

Did Commodore expect customers with NTSC Amigas to enjoying playing PAL games in black and white?

As such, why did Commodore even have the PAL/NTSC boot option in the first place (since there was the option of using the RGB connection which would not encounter these issues)?

Regards,
ed...

[deicidal]

Something that ive always wondered about is why did the a500 have a mono output on the back? I expect there is an obviouse answer for this.

[meega]

Here is something that I recall distinctly.

I used to have a Sony Trinitron 20" video monitor - not a television - intended for conference hall use, etc. I used it with composite output from my UK-spec A1200. When I selected a genuine NTSC screenmode, I got Never Twice the Same Colour hue swings. Yummy. When I set a PAL screenmode it was correct colour.

Just throwing that in here.

[meega]

Originally Posted by deicidal

Something that ive always wondered about is why did the a500 have a mono output on the back? I expect there is an obviouse answer for this.

It was cheaper. It is also very sharp. If you just want to do spreadsheets, text editing, et al., it's good.

[Toni Wilen]

Originally Posted by meega

I used to have a Sony Trinitron 20" video monitor - not a television - intended for conference hall use, etc. I used it with composite output from my UK-spec A1200. When I selected a genuine NTSC screenmode, I got Never Twice the Same Colour hue swings. Yummy. When I set a PAL screenmode it was correct colour.

I checked A1200 schematics, it looks like Alice has PAL/NTSC output signal (OCS/ECS Agnus only have input signal) that is connected to to video encoder's (CXA1145) PAL/NTSC pin. Surprises never end

A600 has same encoder but PAL/NTSC pin is hardwired. Older models use old video encoders that need different external components for PAL and NTSC.

But there is one remaining problem, schematics also shows "PAL Only" circuit before the encoder chip that most likely isn't included in NTSC models (for cost reasons) Perhaps it can also (partially?) mess up PAL Amiga 1200 in NTSC mode?

If schematics are correct, it should be really easy to convert PAL A600 or A1200 to NTSC (bypass the PAL Only part and rewire A600 PAL/NTSC signal line) but NTSC to PAL is more difficult. Except... perhaps it also requires NTSC main crystal..

[meega]

Originally Posted by Toni Wilen

But there is one remaining problem, schematics also shows "PAL Only" circuit before the encoder chip that most likely isn't included in NTSC models (for cost reasons) Perhaps it can also (partially?) mess up PAL Amiga 1200 in NTSC mode?

Boot and get into Workbench, set NeverTwiceSameColor screenmode, launch a program that opens a new screen, flip back to the Workbench and check the colours. They are likely not the same as they were. Repeat ad nauseam.

That's what used to happen, and it's precisely correct behaviour, which is why American televisions (years ago) had hue controls - so you can adjust the green/blue/purply faces after changing channels.

PAL screenmodes were stable.

[Toni Wilen]

Originally Posted by meega

Boot and get into Workbench, set NeverTwiceSameColor screenmode, launch a program that opens a new screen, flip back to the Workbench and check the colours. They are likely not the same as they were. Repeat ad nauseam.

That's what used to happen, and it's precisely correct behaviour, which is why American televisions (years ago) had hue controls - so you can adjust the green/blue/purply faces after changing channels.

PAL screenmodes were stable.

I know but I think that extra PAL circuit can make colors even more uglier.

[meega]

They were pretty enough.

Just not reliable.