ok, then from what i can guess, you have a rev6/6a mainboard with a 1Meg agnus onboard. it seems to have had the jumper/cut mod done on it to get 1Meg chipram. converting what would have been a 512/512 chip/slow to a 512/512 chip/chip config. the first 512 being the motherboard ram, the 2nd 512 being the trapdoor / empty motherboard spaces.
to get more ram in the trapdoor, you'll need either, (and i have seen these) a trapdoor ram expansion that has a pass through that you bolt your existing trapdoor expansion onto, or something like an ICD adram 540, or solder chips to the mainboard and route some signal lines from gary to the trapdoor. either way, you'll need something that grabs some addressing signals from the gary chip.
best thing to do is get a sidecar expansion if you want more ram. plus it'll be faster as the cpu isn't having to go over the custom chip bus to get to the memory, which is what it has to do for "slow" fast ram, and why "slow" fast ram is convertable to chipram, as it is on the chipram bus.
you'll never get more than 1Meg of chip ram in there without upgrading to a 2Meg agnus which doesn't fit the socket you have., hence the minimegachip upgrade boards
thinking about it as i type this, i think for the 1Mb chip / 512k (slow)fast you are asking about, still needs a 2Meg agnus as it is the agnus chip that controls access to memory in that address range. and i guess this would not be possible without a minimegachip 2Meg agnus upgrade board. but then, how did the Adram boards work putting 1.8Mb into the trapdoor slot? :crazy:
forget adding more ram to the trapdoor, get a 2-8Mb side expansion off of ebay for 30 quid or something :-)
