jewell@athena.mit.edu (Darrin B Jewell) (12/29/90)
I have a true B series IBM PC that originally had 256k on the motherboard in four bank of 64k chips. I am attempting to upgrade this to 640k on the motherboard. Banks 0 and 1 have been replaced with 256k chips already, and i left the 64k chips in banks 3 and 4. To complete the upgrade, i believe i have to add address lines to the new chips. I heard that this involved replacing a PAL (programmable array logic chip) and possible adding a few lines. These are procedures i can handle, however i need the info on how to carry out this upgrade. I also may be wrong about the method, but i know the procedure can be done, and is not too complicated. The ROM on board is, to my knowledge able to handle this upgrade. If anyone has any information regarding this upgrade, I would appreciate it if they could please forward it to me. E-mail is appreciated, and a summary will be posted Thank you all in advance. -darrin -- Darrin Jewell ----------jewell@athena.mit.edu-----------------KA2ZLZ------ 4 Ames Street | Massassachusetts Insttute of Technology | Darrin B. Jewell Cambridge MA | Senior House -- Runkle 304 | 8 Thomaston Lane USA 02139 | check out twin peaks color gif files | Orchard Park, NY (617)225-6771 | in /pub/twin-peaks | USA 14127-2526 (617)225-6624 | at anon ftp freebie.engin.umich.edu | (716) 662-9440