I see that there are component changes around the Telephone Modem interface.
Here in Australia, we used CCITT for our modem standards, so I modified my M100 to use CCITT V.21 tones (1750/1850Hz) instead of Bell 103 tones (1270/1079Hz) - It was a massive undertaking for a Trainee Technical Officer, but I was pretty pleased when it worked. Direct Connect M100 - No need for my Acoustic Coupler any more!... Of course it didn't meet the Australian Standard for line isolation ;-) Kindest regards, Doug Jackson em: [email protected] ph: 0414 986878 Follow my amateur radio adventures at vk1zdj.net On Wed, 25 Oct 2023 at 09:20, Ken St. Cyr <[email protected]> wrote: > I don't think you're wrong - all of my M100s are 110CH1X. 1010 certainly > seems to be an earlier revision of the board. Just curious - what's the > date code on the CPU? I can't make it out with the cap in the way. Also, > if you're up for dumping the ROM, it would be interesting to compare it to > a 'released' version. > > //Ken S. > ------------------------------ > *From:* M100 <[email protected]> on behalf of Josh Malone > <[email protected]> > *Sent:* Tuesday, October 24, 2023 12:07 PM > *To:* [email protected] <[email protected]> > *Subject:* Re: [M100] Possible M100 prototype. > > Off the top of my head, I don't recognize that artwork number: PLX > 1010H1X. Am I wrong here? > > And, wow, this thing is bodge city. Almost like the Tandy 1400FD that I > have. (that I still don't know the story behind the bodges) > > -Josh > > On Tue, Oct 24, 2023 at 11:38 AM <[email protected]> wrote: > > All, > > > > I recently attended Tandy Assembly 2023 and Eric Dittman asked me to recap > an M100 that had belonged to Frank Durda an engineer at Tandy. I did not > pay much attention to it at the time but when I took it apart last night, I > was not sure what I was looking at. The PCB is a US type but has dozens of > modifications and is a bit different than any other one I have seen. > > I then noticed it was missing the TRS-80 Model 100 badge, the FCC label > and it had no serial number. Now I’m thinking this might be a prototype > machine. I took a few quick pictures, link below. I plan to take some > higher quality images and document the modifications as well as I can. The > goal it to get it working but not alter it more than required. The only > caps that look like they are leaking at the 10uf (which are normally the > worst ones), so I will start with those and the memory battery and see if > it springs to life. > > https://1drv.ms/u/s!AtH4vpaZnzX7mKBV07xl8qlMDuc6QA?e=UfFBVx > > Thoughts? > > Jeff BIrt > >
