Re: HP42s Memory Upgrade Questions. Message #5 Posted by randy on 16 Oct 2007, 5:16 p.m., in response to message #1 by Thomas Chrapkiewicz
Quote: Is the 32kx8 SRAM from a dead HP48 or HP38 a satisfactory device or is the current consumption prohibitive?
They are CMOS static devices and as such the standby current is, in the scheme of things, insignificant. Active current is not a concern either...
Quote: Are there more modern SRAM ICs available that could substitute for the 62256
What's wrong with the "older" devices? IMO, there is absolutely no reason not to use the older Fujitsu/Winbond/Sony/Toshiba 256kb devices found in the 48 and 38G's. I've used them all, along with some Cypress parts I bought early on. I found no difference in battery life regardless of which device was used.
The bigger and more important question is the one you should be asking yourself: Why do I need 32K in a 42S?
The thought of having to enter even 8k's worth of programs is enough to put me off the task. Loosing that much work would be very, very painful.
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