DRAM chips

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Model A/B

The Model B uses a total of sixteen 4816 DRAM chips to give it 32K of RAM. These chips are arranged in two banks of eight chips, /CAS0 and /CAS1. Each chip provides one bit of storage for 16,536 (16K) memory locations. The Model A uses only one bank, /CAS1. The use of either or both memory banks is controlled by selection jumper S25.

Errors in a particular bit will correspond to a specific IC:

Model A/B
/CAS0 /CAS1
D0 IC61 IC53
D1 IC62 IC54
D2 IC63 IC55
D3 IC64 IC56
D4 IC65 IC57
D5 IC66 IC58
D6 IC67 IC59
D7 IC68 IC60