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Author Topic: Amiga 500 rev. 6A 1 MB chipRAM + 0,5 or 1 MB fastRAM possible?  (Read 6527 times)

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Offline RiP

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Quote from: Blizzard 128 MB;799094
I saw all of the expansion here:
http://www.bigbookofamigahardware.com/bboah/CategoryList.aspx?id=28
A Gary adaptor and wire+GAL is needed for the all 1,5, 2, 4 MB trapdoor fastRAM expansion card.

Rev. 6 motherboard 1 MB chipRAM (1 MB Agnus) + 0,5 or 1 MB fastRAM possible with trapdoor card, but how?
A500+ rev. 8 motherboard with 2 MB Agnus = 2 MB chipRAM simple. 1 MB chipRAM on motherboard + 1 MB expansion card.
I use in 2010  a rev. 6 motherboard (0,5 MB chipRAM) machine + a 1 MB expansion card.
The result: 0,5 MB chipRAM and 0,5 MB fastRAM.
A500+ rev. 8 motherboard 1 MB chipRAM + 0,5 or 1 MB fastRAM how possible with trapdoor card?
The same may be the solution both motherboards.

1 MB chipRAM + 2 or 4 MB fastRAM possible with rev. 6, or rev. 8 motherboards?
Or 0,5 MB chipRAM + 2 or 4 MB fastRAM possible only with trapdoor card?
Example:
http://www.bigbookofamigahardware.com/bboah/product.aspx?id=1067
http://www.bigbookofamigahardware.com/bboah/product.aspx?id=1015

I connected the 0,5 MB fastRAM card to the trapdoor slot (1 MB chipRAM rev 6 motherboard), the fastRAM not exist.
The J7A jumper cut (0,5 to 1 MB operation) = trapdoor slot off.
I restored the J7A jumper to the original state, but the machine did not work.
I cut J7A, A500 work. The Gary wire necessary.
Without Gary wire 1 MB chipRAM + 0 MB fastRAM, or 0,5 MB chipRAM + 0,5 MB fastRAM possible only.

I  do not want to buy a RAM expansion card, or rev. 8 motherboard. I want  to use my rev. 6  1 MB chipRAM motherboard + 0,5 MB fastRAM only.
There may not be big disadvantage, if I expand the motherboard onto 1 MB.


How to wire Gary? :confused: