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Old 19 September 2009, 21:19   #1
xlar54
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A2000 PAL / NTSC change?

Hey guys, I have an A2000 that is set to PAL on bootup. I can change it via both mouse buttons, but thats annoying. Is there a jumper or something to set it permanently to NTSC?
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Old 20 September 2009, 00:20   #2
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Yes, but it is not apparent.

It is a solder pad on the motherboard and depends on the A2000 model where it is and if the hack will work (depends on the Agnus version you have).

8370/8371 (512kb Agnus) must be swapped to the hack work on the old (pre-6.x revision) boards. ECS Amigas (2Mb Agnus) also have this limitation.

Just the 6.x board with the 8372A got this "ability". I did the contrary: converted a NTSC machine to PAL because most games are PAL.
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Old 20 September 2009, 02:46   #3
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If you can afford one, it would be easier to get an Indivision ECS so you can use a PC monitor instead of a TV.
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Old 20 September 2009, 06:33   #4
xlar54
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Quote:
Originally Posted by alexh View Post
If you can afford one, it would be easier to get an Indivision ECS so you can use a PC monitor instead of a TV.

I actually have a 1084 monitor. Ill have to see if the hack mentioned above is something i can do.
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Old 20 September 2009, 07:59   #5
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It's just removing the pin 41 of Agnus from ground and routing it to +5V, but the other above requirements must be sated.
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Old 03 January 2020, 06:04   #6
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I realize it's been 11 years, but I must correct Rkhauer in regards to"Just the 6.x board with the 8372A got this "ability". Like he suggests, with the exception of the original "German" A2000, All Rev 4 & later (B2000) have the J102 jumper (cut type) to set PAL/NTSC booting. However, the limitation in all cases (excepting the exclusive A500+/A600 Agnus's) is based on whether or not an 8372A is present, and that too, applies to rev 6x boards. All B2000 boards were made with 1MB Agnus upgrade in mind, accomplished by replacing Agnus, cutting J500 and moving J101 to position 2. It is recommended to also replace the main XTAL accordingly, since a "switched" Agnus performs a little better at full frequency, and the difference may even be noticeable with certain programs. If anyboy out there knows for certain (officially, not guessing) that A2000 PAL/NTSC boards are identical in all other respects, please let me know. As of now I'm certain that A500 (at least rev 5) is different in at least 3 missing components on the PAL version, A600 & 1200 are different not only in the RF box but also in other areas. The presence of a socketed main XTAL in the A3000 & A4000 (at least the ones I've had) suggests they are indentical. Please comment.
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Old 03 January 2020, 09:26   #7
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All the component changes you need are the correct Agnus and the correct crystal to convert the A2000. I recommend using the crystal that corresponds to the screen mode the machine will mainly be used in.
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Old 04 January 2020, 02:22   #8
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You should definitely make sure you have the correct NTSC or PAL crystal. Both the custom chipset and AmigaOS set their internal timers based on the assumption that the crystal matches the NTSC/PAL pin/jumper.

If they don't match you can get random glitches/slowdown on stuff that assumes an exact correlation between I/O and system ticks, and your system clock will also drift off of real time (breaking stuff that demands clock synchronization like encrypted network connections and such).

I used to jumper my NTSC A4000 to boot into PAL without realizing the xtal difference, and slowly noticed the weird issues and didn't understand why they were happening. (My first warning was ssh stopped working after a few hours, and some games would glitch frames sometimes).
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Old 04 January 2020, 04:41   #9
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I can verify, with no uncertainty, that just grounding a pin, or closing a jumper won't work. I just built an A2000 from a replica board, in which I installed a PAL oscillator crystal. I forgot that I had, and, the next weekend, when I finished up all the soldering, I closed the NTSC jumper pads. Well, nothing worked correctly -- all the RAM would not be detected, I had all sorts of random graphical glitches and the computer crashed randomly. I also had incorrect color on all screens. After tinkering with it for another weekend, in which I reflowed all joints, looked over every single point on the board, and still had issues, it dawned on me that the crystal speed was PAL, and I forgotten using it instead of an NTSC speed one! Once I opened up the jumper, the 8732A (bimodal) Agnus functioned perfectly and the computer has been flawless since then.
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Old 09 January 2020, 05:58   #10
Ric
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Kirk M, are you sure J500 was open in the beginning? (although that shouldn't have caused such a mess). Being in The States, I must admit that I've never tried switching an A2000 with a PAL oscillator & 8372A to NTSC, but the opposite I have, and the A2000 will behave in both PAL & NTSC, except for the aforementioned timing problems with certain software. I don't know, maybe the road is a lot rockier when Agnus tries to derive faster frequencies from a slower crystal, or maybe some of your re-build components were different.
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