Brainstorm's unlabeled replacement chip for Apple's TSM on the Mac Plus logic board, taking over control of DRAM refresh timing.

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1. Keith Kaisershot (blitter@mastodon.social)'s status on Wednesday, 31-Jan-2024 04:43:04 JST Keith Kaisershot

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   Elsewhere on the Mac Plus logic board, the TSM-- a PAL16R4A-- is replaced by its unlabeled Brainstorm equivalent. This chip controls the frequency of DRAM refresh and its timing is coupled to that of the CPU. (I tried running my Plus with this replacement TSM but without the Brainstorm board, and while the Plus did attempt to start, its chime was razzy and the video display was unrecognizably scrambled.)