Keep in mind that supercaps have a high self-discharge rate. From the measurements I did when I put a 2.5F cap in my M100 I’m guessing it would back up the full complement of RAM for about 2 days. The original NiCad would last about a week will 4 option RAMs. That being said I don’t see a huge problem with a 2 day backup incase the AA are completely dead.
Jeff From: M100 <[email protected]> On Behalf Of Josh Malone Sent: Wednesday, July 25, 2018 11:17 AM To: [email protected] Subject: Re: [M100] New User - Resurrected T102 Welcome to the club! Congratulations and Thanks on/for restoring a M102. I have a 102 as my "daily driver" and hope to also repair a couple of problematic 100s in the near future. Thanks, also, for the part numbers. I'm debating cap-vs-nimh for my restores. My recent experience with a capped 100 is leaning me in that direction. -Josh On Wed, Jul 25, 2018 at 12:11 PM, Andy Lawrence <[email protected] <mailto:[email protected]> > wrote: Hello All, I was born in 1975, and throughout the 80s I looked forward to the annual Radio Shack catalogs, each year drooling over the T100/2s etc! Well a couple weeks ago I was cruising eBay and ran across a busted T102 and snatched it up cheap. Completed the following to fix it up: - Restored normal functionality by re-soldering the DC jack. - Burned y2k ROM, thanks to GregS for pointing out the file location. I was planning to burn on a stash of old 27c256s, but appears I've used all of those, rather than eBaying surplus I simply ordered an AT27C256R-70PU-ND from Digikey for $1.38. This also saved me 2mA. - Swapped the leaking NiCad for a 4F Supercap, Digikey part 4704PHBK-ND. - Swapped the original 32.768k crystal for a Digikey part 300-8763-ND, which is 4PPM part, though I didn't test the original this new part should help keep better time. - Followed the 8-Bit Guy's YouTube's guide to "Retro Bright" the yellowed plastic, which turned out great aside from slightly damaging the Tandy T102 black plastic emblem by getting it too warm. :crying: Anybody have one of these laying around? I was utilizing a halogen lamp to warm the solution, got it too close... Though I don't have any specific plans for the T102 (right now it's calculating prime numbers), I've already acquired a T200, which will receive similar treatment! I'm really glad to see communities like this still active, brings back such great memories! I might even start a retro Z80/68000/etc or similar build, fun times ahead. Many thanks to all and have a great day. Andy
