Great job fixing MSPLAN! I have never heard of a reason for the pin to be bent under. All I can think is that perhaps this machine used to be attached to something over the System Bus connector and the ROM had to be disabled to not interfere.
For the missing RAM, you may already know this, but one of the interesting things about the Tandy 200 is that it doesn’t differentiate between storage and memory. So, if you save a file that is 1,466 bytes, your working RAM will be reduced by the same amount. Try hitting F1 from the MENU to switch to a different bank of 24K and see if that changes things. … wait a minute! Actually, now that I’m writing it, I am realizing that you said HIMEM was reduced, so forget what I said about files. HIMEM marks the start of the portion of memory which is off-limits to BASIC and it can be changed with the CLEAR command. This is useful to stash machine language programs, such as AsciiPixels <http://club100.org/memfiles/index.php?direction=0&order=&directory=Ken%20Pettit/AsciiPixels>. To reset BASIC back to using the maximum amount of RAM you can do this: CLEAR 256, MAXRAM —b9 On Wed, Aug 7, 2024 at 9:37 AM Tom Blum <[email protected]> wrote: > I'm having fun now. And success getting MSPlan running. Plus a new > mystery. > > A close inspection of the T200 insides found the following: > > 1. Light corrosion on the negative terminal of the backup battery; will > replace that as soon as the new NiMH battery arrives > 2. a bit of the coating on thermistor TH2 chipped away, component still > functioning (see below) > 3. no signs of leaking capacitors or fluid/liquid intrusion > 4. no signs of degradation or consequential damage to traces > 5. on the bottom of the main PCB, some surface mounted components with > discoloration around the mounting pads and on parts of the components: > R185, M30, M32, T17-T19 in particular (see below). All of my vintage > computer experience has been with Ohio Scientific boards manufactured > before 1980 and not involving components at these small scales. I can't > tell if the discoloration is due to excess flux or some sort of discharge. > Whatever the cause, the system is functioning. I'm certain I don't have > the skill/steady hands to work with components on this scale. > 6. No sign that anyone previously mucked around inside the system > > 7. The MSPlan ROM (M14) was installed with pin 10 bent all the way under > the IC. Before reseating the ROM, I bent the pin back out. > > Once the M14 ROM was reseated and the unit reassembled, MSPlan launched > just as it should. And all other ROM-based applications launch as they > should. BUT.... > *New mystery*: the system now reports in BASIC 17,868 bytes free -- > that is 1,466 bytes fewer than should be the case. HIMEM is also reduced > by 1,466 bytes. > > Now I am wondering if pin 10 was supposed to be left bent under and the > ROM just needed to be reseated. Exactly how that would relate to the > availability or non-availability of 1,466 bytes I don't know. > > Tom > > > > On Tue, Aug 6, 2024 at 9:40 PM B 9 <[email protected]> wrote: > >> Brian is right that whatever happened to make tge builtin ROM disappear >> is pretty serious. Birt has some good videos >> <https://www.youtube.com/watch?v=1adlQo3UI90> on fixing up such problems >> on his YouTube channel <https://www.youtube.com/@HeyBirt>. Even if you >> don't have the time right now to completely fix it, it would be good to >> open it and clean up any corrosion. >> >> One last thing to try, although I'm pretty sure it will be exactly like >> running it from the menu: On my Tandy 200 you can launch MSPLAN from BASIC >> by using `CALL 61167, 1`. What does it do on yours? >> >> —b9 >> >> On Tue, Aug 6, 2024 at 8:00 AM Brian K. White <[email protected]> >> wrote: >> >>> I can only confirm that MSPLAN works with no option rom installed. >>> >>> Could be either bad ram or bad rom. There are two rom chips inside >>> besides the option rom socket outside. Or anything else like a corroded >>> trace making a stuck address line. These units all have leaking caps and >>> batteries by now, even if they are still working. >>> >>> Don't be loath to open it, run to open it to arrest the development from >>> getting worse as soon as possible. >>> >>> -- >>> bkw >>> >>> >>> On 8/5/24 09:51, B 9 wrote: >>> > That's actually pretty cool and I'm curious what GTE's firmware does. >>> > What software version are you seeing? >>> > >>> > I'm not sure why they would overwrite MSPLAN yet leave it in the menu, >>> > but if they added an "option ROM", I believe you can run it with `CALL >>> > 61167, 2`. >>> > >>> > —b9 >>> > >>> > >>> > On Sun, Aug 4, 2024 at 6:10 PM Tom Blum <[email protected] >>> > <mailto:[email protected]>> wrote: >>> > >>> > Hello, >>> > >>> > New to the community and apologies if I'm raising a question/issue >>> > already addressed. Just purchased a working T200. Power cycles >>> > nominally and shows classic menu options. Selecting Multiplan from >>> > the menu places the T200 into a frozen state. LCD screen appears >>> to >>> > fill (shaded) completely but program does not start, no visible >>> > text/graphics. Resetting and power-cycle necessary to get back to >>> > the main T200 menu. Noted that this T200 has a property label on >>> > the bottom indicating that GTE, Inc. (the telecom company) was a >>> > previous owner and appears to show a unique GTE software version >>> #. >>> > Is it possible that the original/built-in Multiplan ROM was (or >>> > could be) removed from the T200. As a newbie to the T, am loathe >>> to >>> > open up a working unit to see if a ROM is missing. Is there a past >>> > or present ROM option module for the T200 that would have Multiplan >>> > installed (or installable)? Tom >>> > >>> >>> -- >>> bkw >>> >>>
