A1200 rev 1D4 NTSC motherboard to PAL conversion

Hello dear Amiga enthusiasts,

I have recently bought an new A1200 mobo to replace a malfunctioning one I had on my A1200.

However, since a PAL (like my old one) is not so easy to find (out of stock), and knowing there was a hardware hack available to convert the NTSC to PAL (disconnect Alice's pin 41 from mobo), I ordered a NTSC board.

As soon as the board arrived, I unwelded pin 41 hoping to get my machine to boot in PAL mode per default. This seems to be the case, however I'm afraid something went wrong: I get no color (black/white) and vertical stripes on the screen (and jumpy image sometimes).

If I select a NTSC screen-mode on WB it all works fine (color-wise), but my WHDLoad games (PAL) do still have a problem.

I have read all the threads I could fine here on the topic, and I'm a bit confused :

-sometimes it is mentioned that the lift-up pin 41 needs to be connected to +5V with a 4k7 resistor;

-sometimes it is mentioned that lifting pin 41 suffices (no need for resistors or +5V). Furthermore, Paulo_Becas has performed this hack this way (simply lifting 41) a couple of times, including on a 1D4 board, and has been successful in getting PAL. I've read about several other people that were also successful in it;

This without having to replace the crystal NTSC/PAL...

I really don't know what's going on, especially because I have the same revision (1D4)... the only difference I can state is that my Alice chip has another reference number: 391010-01 8374-ALICE 3593 23 than Paulo's...

Can someone please shed some light on what I'm doing wrong? what do I need to do to get my PAL games and everything working with my new mobo?

Thanks

[prowler]

Hi vasco_matias, and welcome to EAB.

Have a good read through this thread:
Needed: Info on A1200 NTSC to PAL conversion

[bbond007]

Originally Posted by vasco_matias

Hello dear Amiga enthusiasts,

I have recently bought an new A1200 mobo to replace a malfunctioning one I had on my A1200.

However, since a PAL (like my old one) is not so easy to find (out of stock), and knowing there was a hardware hack available to convert the NTSC to PAL (disconnect Alice's pin 41 from mobo), I ordered a NTSC board.

As soon as the board arrived, I unwelded pin 41 hoping to get my machine to boot in PAL mode per default. This seems to be the case, however I'm afraid something went wrong: I get no color (black/white) and vertical stripes on the screen (and jumpy image sometimes).

If I select a NTSC screen-mode on WB it all works fine (color-wise), but my WHDLoad games (PAL) do still have a problem.

I have read all the threads I could fine here on the topic, and I'm a bit confused :

-sometimes it is mentioned that the lift-up pin 41 needs to be connected to +5V with a 4k7 resistor;

-sometimes it is mentioned that lifting pin 41 suffices (no need for resistors or +5V). Furthermore, Paulo_Becas has performed this hack this way (simply lifting 41) a couple of times, including on a 1D4 board, and has been successful in getting PAL. I've read about several other people that were also successful in it;

This without having to replace the crystal NTSC/PAL...

I really don't know what's going on, especially because I have the same revision (1D4)... the only difference I can state is that my Alice chip has another reference number: 391010-01 8374-ALICE 3593 23 than Paulo's...

Can someone please shed some light on what I'm doing wrong? what do I need to do to get my PAL games and everything working with my new mobo?

Thanks

What you did is convert the machine from 60 to 50 HZ.. What you know have is a hybrid standard (NTSC 50). Your color signal information is still NTSC. This is the same as picking "PAL" from the early boot menu...

Truly converting the machine to PAL is more involved and you'll need to replace some surface mount components to make the composite signal PAL. I'm pretty sure you just need to change a few caps or resistors, not the ALICE...

I would suggest using a converter than uses the RGB port such as the AmigaManiac SVIDEO adapter.

I learned this from reading the CD32 FAQ. CD32 users are SOL because they don't have RGB ports...

Hope that helps...

Originally Posted by bbond007

What you did is convert the machine from 60 to 50 HZ.. What you know have is a hybrid standard (NTSC 50). Your color signal information is still NTSC. This is the same as picking "PAL" from the early boot menu...

Truly converting the machine to PAL is more involved and you'll need to replace some surface mount components to make the composite signal PAL. I'm pretty sure you just need to change a few caps or resistors, not the ALICE...

I would suggest using a converter than uses the RGB port such as the AmigaManiac SVIDEO adapter.

I learned this from reading the CD32 FAQ. CD32 users are SOL because they don't have RGB ports...

Hope that helps...

Thanks, this clarified some things... still I don't understand why the pin 41 hack worked in some cases but not in mine... probably related to the fact that I'm using a TV (scart or RF) to visualize the signal. Probably a monitor will have another behavior...

Ultimately, my aim is to get a flicker-fixer (like this one: http://www.vesalia.de/e_indivisionagamk2.htm) to connect my A1200 to an LCD PC monitor. Would you reckon this would work without problems with my NTSC (now hybrid) board? the flicker-fixer is kind of expensive and if I doubt it's going to work I'll hold my order...

[TjLaZer]

Not sure why is has been so hard for you to find a proper PAL 1200 motherboard. They are so much more common than NTSC!!! I see the PAL ones on eBay all the time. Hardly ever do I see NTSC. Maybe you can sell it and just get a PAL one. (and even make a huge profit!)

Edit, here are THREE for sale right now:
http://www.ebay.co.uk/sch/i.html?_tr...board&_sacat=0

[bbond007]

Originally Posted by vasco_matias

Thanks, this clarified some things... still I don't understand why the pin 41 hack worked in some cases but not in mine... probably related to the fact that I'm using a TV (scart or RF) to visualize the signal. Probably a monitor will have another behavior...

Ultimately, my aim is to get a flicker-fixer (like this one: http://www.vesalia.de/e_indivisionagamk2.htm) to connect my A1200 to an LCD PC monitor. Would you reckon this would work without problems with my NTSC (now hybrid) board? the flicker-fixer is kind of expensive and if I doubt it's going to work I'll hold my order...

I went through all this with a NTSC CD32 which is worse because there is very little NTSC software.

The results were different on different screens... Some worked perfectly well, some B/W...

I feel your pain... I would have been better off with a PAL CD32, and I'm in the US.

The Indivision will make it all better hopefully. I love mine, but be aware it may not be 100% compatible with your screens either... until the firmware is done. It does not work at all in VGA or HDMI with my LG TV. Works perfectly with my Samsung monitor in HDMI...