Re: faulty 41cv memory chip Message #4 Posted by Tony Duell on 24 Jan 2005, 4:02 p.m., in response to message #3 by g. fernandez
If you take the memory module apart, you can desolder the connector from the PCB, leaving 12 pads in a line. 2 of those (or equivalently 2 of the pins on the connector) are B3 and B4.
I assume you have an HP41 service manual. The pinout of the port is shown there. B3 and B4 are labelled. If you can't find it, I'll look it up for you.
The memory chips inside the 41 are designed to respond to particular addresses. That's the difference, I think, between the -0004 and -0005 chips. Corresponding pins on the different RAM chips are linked together on the PCB, there is no external chip select logic.
|