thad@cup.portal.com (Thad P Floryan) (01/12/90)
Peter Fales comments: "Or (perhaps easier/safer) performing a solder gun upgrade on the .5 MB card." referring to adding more memory in the UNIXPC. I've received several requests regarding a 1MB-to-2MB upgrade after my 512K- to-2MB "How to do it" posting. I've never seen a 1MB-only motherboard and am still researching the answer; it probably IS very easy, but I want to check the answer before posting, and am looking for a 1MB motherboard in this area. It's "probably" going to be "only" a matter of adding sockets and the chips, since the address decoder (on the 1MB board) is already setup for the 256Kx1 chips. Concerning the 512K RAM expansion board modification (to become a 2MB exp. RAM card), I'm working on that, too. Yes, John Milton has posted very clear instructions in the past (and they're available in his HWNotes series of articles), but I've just noticed there are (at least) TWO variations of the 512K expansion RAM card: the "Rev.B" and the "Rev.D" ... there are some trace and "jumper" differences which are immediately obvious to the eye. I'm still looking for a "Rev.C" card. What "may" need to be done is to upgrade a "B" (and "C" ?) to be a "D", then upgrade to 2MB; I've at least one of each board and will be experimenting. Results and "how to" will be posted for both the above. BTW, if anyone is looking for RAM chips, I've never seen the prices any lower than they are presently: at a "consumer" electronics store in this area (Fry's Electronics), 80nS 256Kx1 brand-new, last-week's production code, DRAM chips are only $2.19 each in quantity ONE! These chips (Samsung) work perfectly in the UNIXPC and its expansion cards. Fry's also carries the proper sockets and batteries for the UNIXPC if you need to do the battery replacement, and Fry's also handles telephone and mail orders (they already have two stores here in Silicon Valley), and they accept cash, checks, VISA and M/C Ref: Lithium battery holder, Fry's part# 60050, $1.29 each Lithium battery, Ray-O-Vac "Lifex" Computer Clock Battery BR2325, Fry's part# 12810, $1.99 each "1 Meg-x-9-70nS SIMMs" at $99 each ===> "256K-80" at $2.19 The RAM prices are guaranteed until Jan.16 (per their ad). I just bought some, and I highly recommend Fry's when they have special deals like this. Fry's Electronics 541 Lakeside Drive Sunnyvale, CA (dunno ZIP, it's not in their newspaper ad, but they're within 1 block of the AT&T West Coast Training Center) (408) 733-1770 Mon-Fri 8am-8pm Pacific Time Sat-Sun 9am-6pm Thad Floryan [ thad@cup.portal.com (OR) ..!sun!portal!cup.portal.com!thad ]