Xerox 820-II component parts were available from Xerox outlet stores at quite reasonable prices, and it was not uncommon to convert surplus (but new) 128 kiB 16-bit processor cards to 512 kiB by the substitution of sixteen 41256 DRAM chips for the card's usual sixteen 4164 DRAM chips (both are 16-pin DIPs—pin 1 is unused on a 4164 and becomes A8 on a 41256), plus the addition of two ICs (one 74F02 and one 74F08, or two user-modified PALs) for controlling the 41256's 9th address row and column (not found on 4164s), thereby achieving a four-times increase in RAM without the use of a "daughter" card (which can only achieve a two-times increase in RAM).