HP Forum Archive 11

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HP 9810 Message #1 Posted by olivier croissant on 25 Mar 2003, 4:24 p.m. Hi, I am thinking about buying a HP 9810 with the basic memory configuration. I have two questions: Does someone know a way to add memory using market devices to reach its full potential? Are such machine rare ? How much should i expect to pay for such a machine? Thanks

Re: HP 9810 Message #2 Posted by andy on 25 Mar 2003, 4:38 p.m., in response to message #1 by olivier croissant There's one on ebay right now: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=11713&item=3014516072 I've seen 1 or two on ebay in the last year.

Re: HP 9810 Message #3 Posted by Tony Duell (UK) on 25 Mar 2003, 6:39 p.m., in response to message #1 by olivier croissant The memory in the 9810 is consists of Intel 1103 DRAM chips. These are 1K bit devices, and 3 of them are used for each block of program memory. Hardware in the memory cage does 2 physical accesses to the memory for each CPU memory access, and fiddles with the bits so that the 1K*3 physical memory appears as 512 6-bit 'program steps' to the CPU and to the user (the 9810 stores the program as 6 bit keycodes). The 1103s are early PMOS memory chips and have strange supply rails (+16V and +19V) and logic levels. In the 9810, the TTL signals used by the rest of the machine are converted to/from these strange levels by circuitry on the memory timing/address/data PCBs -- the RAM PCBs are just the 1103 chips, and the signals at the RAM PCB edge connector are at these strange levels. It is therefore non-trivial to use anything other than 1103s in the 9810. And I have no idea where you'd get those from these days.

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