|Re: hp 9815a/s repair|
Message #26 Posted by frankabc on 26 Sept 2009, 3:31 p.m.,
in response to message #25 by Joel Setton (France)
Dear Eric and Joel, Saturday, 9/26/2009
Here are the numbers of the white ROM IC's for our 9815a and our 9815s. As for the position of the chips, I am viewing the keyboard section inverted (i.e. upside down), and rotated so the white ROM chips are at the top. I then read left-to-right for the uppermost bank of four ROM chips, followed by, left-to-right, the lower bank of one empty slot, followed by three ROM chips.
G1818, 2605, 2693
H1818, 2602, 1363
D1818, 2603, 2696
B1818, 2604, 2801
B1818, 2608, 2668
D1818, 2607, 2783
E1818, 2606, 2455
H1818, 2605, 5640, SINGAPORE
H1818, 2602, 2581, SINGAPORE
D1818, 2603, 5454
B1818, 2604, 5174, SINGAPORE
B1818, 2608, 5633
D1818, 2607, 6149, SINGAPORE
E1818, 2606, 5915
General question: Why has 'most EVERYONE spoken of 2111 memory chips on the 9815a, whilst our 9815a has 2112's (hp 1818-0140)? Is our 9815a unique, or (heaven forbid!) are some recollections foggy?
Thank you, Eric, for the information on possible replacements for the unreliable 2114's, and thank you, Joel, for the patent reference for memory assignments for the RAM chips. Maybe we can order some replacement RAM's soon.
Endless details: Also Joel, when you refer to the two ROMs of your 9815, I assume that yours is an "s" version? So it is interesting that our 9815s has 7 white ROM chips, like our 9815a, while your 9815s has two ROM chips. Our "s" CPU board is REV C, 09815-66514, while you notice that your board is the service part 09815-69512.
Edited: 26 Sept 2009, 3:41 p.m.