A1200 PAL vs NTSC

[nyteschayde]

I recently purchased a nice A1200 complete in the case and a NTSC unit (which I wanted). The problem is that the mobo revision doesn't support Subway USB adapter I bought (the clock port is on the wrong side). I have another A1200 motherboard that is PAL and has the right clock port pins, but my question is, how can I make the PAL motherboard a NTSC one? Are there chips I can swap out? Traces I can cut or build?

Anybody have an idea?

[nyteschayde]

Yeah I can always go back to doing that but I was hoping that I'd somehow be able to swap something and make it happen more easily. We'll see if anybody else has any ideas.

[nyteschayde]

I am in San Jose, CA USA. Actually I'd like to get another Indivision when one crops up but given I live in the States all my games and software are NTSC versions and it's always been a pain for me. Not to mention I hate the flicker of a 50Hz resolution. I can swap at boot but doing that all the time is also a pain.

[nyteschayde]

@OP

How do you know if you have the wrong clockport or not? I have an escom a1200 should it be ok? Or were the non cbm 1200s the problem? I'm wanting a subway.

The documentation for the Subway says if the clockport pins are on the left it won't work. I also tried hooking it up to find it doesn't work. Ergo, the documentation is right. To cement this idea I also have another A1200 in a tower that also has a Subway that has the pins on the right and it works fine.

[nyteschayde]

Yup.

Ground Pin 41 of the Alice chip and the A1200 will boot it up in NTSC mode. If you enter the early startup menu you will see that the machine has defaulted to NTSC. Likewise with a NTSC machine if you lift Pin 41 from its solder point, thereby un-grounding it, the machine will boot to PAL mode. You could even install a toggle switch to control if the machine boots into PAL or NTSC mode. Just don't flip it while the machine is powered on otherwise Alice would probably be toast.



If you are using an RGB monitor everything will be perfectly fine. However the composite video and RF jacks will display incorrectly or black and white (results depends on the TV as some are more tolerant - especially older CRTs). Kipper2K recently posted directions for a full conversion which would make the composite and RF display correctly, but if you are using RGB I wouldn't bother. Full conversion involves a lot of component soldering and desoldering and expense.

Considering the composite and RF video out on them is crap anyways, this isn't much a lost. You could always purchase one of the NTSC/PAL Composite/S-video adapters from Amigamaniac that plugs into the RGB port. I had one and the s-video out is FANTASTIC. Very close to RGB quality. Kipper2k is also working on one that does component video as well.


HOWEVER - Might I ask WHY you want the machine in NTSC mode? Unless you plan on doing genlock video work or hooking it up to a regular TV or similiar, I personally see no need for NTSC. Almost all the good software and certainly nearly all games are in PAL. I like many have been using PAL Amiga's here in the states for years and have been a lot happier with it. More compatible and software runs and plays the way it should. No more speed up music or missing parts of the screen like you normally get with NTSC machines trying to run PAL software. All those excellent Demo's from Europe would play perfectly unlike on NTSC machines. So unless you have a mountain of NTSC software or some other burning desire I wouldn't worry about it.


Also, in case you aren't aware, if you are using an RGB monitor like the 1084, it will display just fine with the PAL A1200. The RGB inputs on them will display both NTSC and PAL fine. Likewise with many (most?) other RGB monitors. I use a JVC broadcast quality monitor via RGB and works fine with both 50 and 60Hz inputs.



Bottom line - If using an RGB monitor, ground Pin 41 of the Alice chip to force the machine into NTSC mode if you really need it. Otherwise hold down both mouse buttons at bootup and switch to NTSC via the early startup screen.

Thanks for the info. I don't have an RGB monitor for my Amiga's which is why this is more important, that and the ridiculous amount of flicker you see when running anything at 50Hz instead of 60Hz in the States. I've always been especially bothered by lower refresh rates, even when there wasn't anything but the two in my world.