NTSC Fat Agnus Part Number?

[jasenr]

I apologize if this is answered somewhere. I looked for a little while and can't find a definitive answer. I have an NTSC Amiga 500. I am wanting to upgrade to the Fat Agnus...? I can't find a clear answer on if the PAL and NTSC use the same chip. People tell me to get the 8732A, but I saw an article that made it sound like that was for PAL machines. I have been upgrading my Amiga as much as I can without going to modern upgrades. That will be my other A500! ;-) I already have an A590 HD and have bumped to an 86010 and 3.1 ROMS. Now I want to get chip RAM up so that I can run WHDLoad on more than a basic Workbench ( I haven't tried yet, but have read that I need 1M chip for it to run ok ).

Thanks for helping!

[hese7]

Here is a list of different Fat Agnus chips:
http://bboah.com/index.php?action=artikel&cat=51&id=2174&artlang=en

[mechy]

I apologize if this is answered somewhere. I looked for a little while and can't find a definitive answer. I have an NTSC Amiga 500. I am wanting to upgrade to the Fat Agnus...? I can't find a clear answer on if the PAL and NTSC use the same chip. People tell me to get the 8732A, but I saw an article that made it sound like that was for PAL machines. I have been upgrading my Amiga as much as I can without going to modern upgrades. That will be my other A500! ;-) I already have an A590 HD and have bumped to an 86010 and 3.1 ROMS. Now I want to get chip RAM up so that I can run WHDLoad on more than a basic Workbench ( I haven't tried yet, but have read that I need 1M chip for it to run ok ).

Thanks for helping!

the 8372A is the correct Agnus for the NTSC 500. Have you upgraded the A590 roms to 7.0 yet?

[Oldsmobile_Mike]

1MB of chip ram is minimum for WHDLoad.  I found a lot of stuff required 2MB, because the operating system consumes a portion of it then you need some left over for games.  1MB chip is easy to do on an A500 though, plug in an 8372A and then do the motherboard mod to convert the trapdoor memory to chip.  People worry too much about this PAL vs. NTSC stuff.    Here's another list of part #'s for you to peruse:

http://en.wikipedia.org/wiki/MOS_Technology_Agnus

[psxphill]

the 8372A is the correct Agnus for the NTSC 500. Have you upgraded the A590 roms to 7.0 yet?

You can also officially use 8375 318069-17 if you rework the board.

http://www.amigawiki.org/lib/exe/fetch.php?media=de:parts:agnus_reworks.pdf
 
 I don't know if any shipped with an 8375, but if it was or the board has already been reworked you'll need the 8375 instead.

[jasenr]

Wow! Thanks for all the replies! I dug around and found some pics of my board I took at the beginning. I have a Rev 6A board. It looks like my Agnus chip is 8372A PN 318069-02. Also, I have indeed upgrading my A590 to the latest ROMs.

Thanks!

[Oldsmobile_Mike]

Great!  In that case all you need to do is the motherboard mod.  Now people on here are gonna tell you there's lots of different ways of doing that, which is true.  Personally I like the method that changes the 512K in your trap door slot into chip ram.  Other folks will tell you to add sockets, or solder chips onto your motherboard, to fill up those blank spots you see now.  Whichever is easier I guess depends on your technical aptitude and amount of time you want to invest in this project.  

If you do a google search there's plenty of threads already on this subject, also docs on Aminet.  Good luck!

[spaceman88]

The trapdoor mod is fairly easy. I think it's just 1 trace to cut and a small solder bridge plus moving a jumper on the trapdoor card.

[psxphill]

Other folks will tell you to add sockets, or solder chips onto your motherboard, to fill up those blank spots you see now.

 I've never heard anyone recommend doing it as nobody seems to have gotten 1mb chip on the motherboard and 0.5mb @ c00000 working. I had a 2mb megachip upgrade that left the trapdoor working though (IIRC it was the one fitted with 2mb so it didn't need to use the motherboard or trapdoor ram for chip ram at all).