Help Identifying RAM Chips

From: John R. Keys Jr. <jrkeys_at_concentric.net>
Date: Sun Nov 2 20:22:33 1997

Your chip #1 is a 64k chip speed of 30ns, chips 2&3 are 256k at 150ns speed.
The last set of tell the the size and speed (64-3 and 256-15). John
At 06:48 AM 11/2/97 -0600, you wrote:
>I have two original Compaq Portables, both of which are giving POST
>errors when they boot which indicate bad RAM. I have gone through a few
>rounds of swapping RAM chips between the machines to identify the bad
>chips, but have come up against a potential roadblock.
>
>My problem is that there are a number of different chips used in the
>machines. As I don't have any data books on these chips, I am not sure
>if the different numbers are simply different manufacturer's numbers for
>the same chips, if some of the numbers are simply date codes, or if they
>are really different, incompatible chips.
>
>If someone is familiar with these numbers, or can look them up for me, I
>would really appreciate it:
>
>Chip #1:
>Hitachi
>1818-3006
>Japan 8332U
>HM4864P-3
>
>Chip #2:
>NEC
>8539PF513
>D41256C-15
>
>Chip #3:
>Fairchild (I think; has an "F" with a bar above and below it)
>MB81256-15
>8548 M79 BC
>
>Chip #4:
>NEC
>8538PF532
>D41256C-15
>
>If you could let me know the size of each chip, as well as the width of
>the memory, it would help me determine what size of RAM I should be
>setting the motherboard DIP switches for. Also, would I be correct in
>assuming the "-15" appearing on most of the chips specifies 15ns?
>
>If anyone is familiar with adding RAM to the motherboard on the Compaq,
>I would appreciate your input on the following:
>
>The machine has 4 banks of RAM, consisting of 8 chips each, plus 1 chip
>for each bank marked "BIT 0". The first two banks of chips (0 & 1) are
>soldered, the other two (2 & 3) are socketed.
>
>1) Is the "BIT 0" chip a parity chip?
>2) Can RAM be installed in Bank 2 without having to populate Bank 3?
>
>Any help in regards to the above is much appreciated!! Thanks in
>advance.
>
>
>
Received on Sun Nov 02 1997 - 20:22:33 GMT