A1200 UK Mobo => NTSC ?

Hi to all

Today I decide to test some A1200 boards I want to sell.

Time a go I bought, at Ebay, one A1200 mobo ID4 labeled as UK one. All components, traces, looks very clean.

Everything works but I have some strange flicking on the screen (I'm using IndiAGA). I tested all conections, power, and everything I know......

Flickin continues.... So I started Scout and....... ¡Surprise! Agnus (Alice) is detected..... NTSC ??????

NTSC mobos from UK? Maybe is a "renamed" mobo? I don't understand...

My old mobo (now is dead :() as worked great without any flicking for long time and if I don't remember bad detectad as PAL by Scout.

Any idea? Maybe I need to buy other mobo?

Thanks

Hi merlinkv

As far as I recall there is some hardware hack to change A1200's alice to PAL mode as default, something about a resistor soldered to some of the Alice's pins and cutting that track.

Keep in mind that it will only change it on the RGB output (i.e. using RGB monitors, Scart or flickerfixer/scandoubler solutions) as the RF and composite outputs will still working with NSTC signals.

And for the labelling don't take it literally, for instance my A4000 is is one of those made ​​in UK, but with U.S specs on labeling (NTSC, 110 volt etc) an then somehow refitted at factory with an a 240V euro spec PSU and that U.S. specs on the labelling crossed out with a permanent marker!:ROTFLOL2:

http://eab.abime.net/showthread.php?t=37701

Pin 41 of Alice.

http://amibay.com/showpost.php?p=60732&postcount=15

desiv
Dang it, Blankstare beat me, but I demand points for using a post on Amibay... ;-)

Hi to all

I'm using IndivisionAGA, not needed RF output or composite.

Quote:

---

- On A1200, route the pin #41 of Alice to either GND or +5V (via a pull-up resistor) and swap the main crystal and RF modulator.

---

So, If I understan well I need to connect the Alice pin 41 to GND and thi is all? One small cable to any GND point in the mobo?

Also I need to "swap" (change?) the main crystal? Is the big one near to the ROM sockets?

Thanks in advance & Best wishes

Yes & yes.

Don't bother with the RF & composite sub-systems, they don't worth the hassle. In fact, sack the RF box out of the Amiga and leave as is.

A bit less power consumption and a good place for external accessing gear (the Indy VGA connector is a good example).

@rkauer

Thanks for the info. I will try next week.

I don't have experience with very small components, but I think I can change the crystal for a new one. :roll:

You can tell me any model/specs of the new crystal I need? I will try to buy one :)

Thanks & Best wishes

14-pin DIL (aka "full can"). PAL is 28.37516MHz and NTSC is 28.6363MHz.

I'm pretty sure someone here can toss one in your general direction from a dead A500+ board.

Hi

Ok, thanks.

Maybe I have one dead A1200 PAL mobo. I will search it... :whistle:

This mod converts the machine in a real PAL A1200?

Changing the resistor on Alice's pin 41, replacing the crystal and nothing more, yes, pretty much.

Only the TV output subsystem will be kept a sort of PAL-60. Just don't bother, not worth the effort to convert this part of the board.