Super Agnus 8375 2MB ChipRam in A2000

[Stormrider]

Hi All
What advantage would it be to install a Super Agnus 8375 2MB ChipRam
in a A2000?

[BinoX]

Umm.. It gives you 1MB more chipram...

[RetroMan]

No, the install of a 8375 Agnus will NOT give you more Chipram, it only makes the A2000 capable of Adressing 2MB ChipRam but you will need to Hack the Board to do so !!!

I dont even know it that is possible to an A2000 Board ... better get a Mini-Megi Chip for your A2000, theres the 8375 on it and 1MB Chip to expand the A2000 ...

[alexh]

The 3875 comes in two flavours, PAL and NTSC. Make sure if you buy one or a Mini-Mega that you get the right one for you.

[billy]

It did come in two flavors, but couldn't you short two pins on the PAL version to fool it into thinking it was NTSC? Or maybe the other way around. I seem to remember something about that but those brain cells are swimming in the darkness right now.

[alexh]

That was the previous version, the 8372, where there was one ASIC for both PAL and NTSC

[billy]

Ah, thanks! I do have the 1MB version in my A2000.

[Malakie]

Since this has not been answered in forever, figured I would ask again... What is the final step to access 2 meg chip ram with the 8375 Agnus on the A2000?

j101 has been switched, j500 has had the jumper removed (rev 6 mainboard, NTSC)

It works fine at 1 meg chip ram with just that, but I would like to also access the other 1 meg this Agnus can address if possible.

I have checked for Mini Megi kits and am unable to find any for sale which leaves me with altering the board myself. Since I restore systems, A1000 and on up, this is not an issue if I can find the procedure to complete the upgrade for the A2000 now.

[SkulleateR]

Should work like this : https://blitterwolf.blogspot.com/201...for-a2000.html

Never did this myself so be warned ....

[Malakie]

Originally Posted by SkulleateR

Should work like this : https://blitterwolf.blogspot.com/201...for-a2000.html

Never did this myself so be warned ....

Thanks will take a look.. I have not done the 2 meg upgrade either. But since I have a machine with the 8375 NTSC 2 meg ship, might as well give it a try.

My only concern.. that hack is for the 8372B chip.. I have an 8375...

[jbilander]

Originally Posted by Malakie

I have checked for Mini Megi kits and am unable to find any for sale which leaves me with altering the board myself. Since I restore systems, A1000 and on up, this is not an issue if I can find the procedure to complete the upgrade for the A2000 now.

You can use LIV2's adapter for A2000 as well. There are two different versions. One is soldered directly to the Motherboard and one uses a PLCC-84-plug.
https://github.com/LIV2/A500-2Meg-Chip-ram/tree/PLCC

Note that it uses the DRAM chip onboard the adapter for the 2MB chip. The motherboard DRAM is not used.

[Malakie]

Originally Posted by jbilander

You can use LIV2's adapter for A2000 as well. There are two different versions. One is soldered directly to the Motherboard and one uses a PLCC-84-plug.
https://github.com/LIV2/A500-2Meg-Chip-ram/tree/PLCC

Note that it uses the DRAM chip onboard the adapter for the 2MB chip. The motherboard DRAM is not used.

K thanks.. am checking for this now.