Hi Jerry, Your cable matches what I would expect for an M100 going to a DVI and it makes sense. There is some pin numbering weirdness because the IDC connector numbering scheme is different than the IC socket numbering scheme, but the pins go straight through as you describe. The cable set I just purchased might have the IC socket incorrectly oriented. I've sent an email to Gregory to try to understand if I'm looking at it incorrectly.
I figured out my confusion with the M102 system bus connector. The machine shows a small arrow on the top side of the connector near the reset button. Looking at the Tandy 102 service manual, that arrow is clearly in the wrong place and pin 1 really is on the bottom row. So that is cleared up, and I'm going to ignore that arrow. Pin 1 is on the bottom row closest to the reset button, and that's consistent with the machine behavior. So back to the cable setup. There is a standard 40 pin IDE cable and then a "twist" adapter. The twist adapter seems to be wrong though - the male pins should just be passing straight through, top to top and bottom to bottom. The twist adapter was switching the top and bottom rows. So I just simply undid the pins and wired them straight through, as Brian White does in his pictures. That got me further. The DVI now detects when I reset the M102 and it appears to by trying to load disk BASIC into memory, but the machine always crashes and becomes non-responsive. Cold starting it recovers it. This is not a good thing. I rewrote the diskette to be sure it wasn't that, and I've checked all of the continuity on the wires. Both machines behave this way. At this point I'm concerned because the cabling that I ordered seems to have been wrong, and god only knows what damage it caused to the two M102s that I was working with. This shouldn't have happened; I purchased the cables to avoid having something like this happen. On Mon, Nov 18, 2024 at 10:27 PM Jerry Davis <[email protected]> wrote: > I sent you a direct message with an image of the cable I'm using. I refer > to the cable I have as a "straight through" cable as the pins on the > M100/M102 match the pins on the DVI. When I lay the DVI cable flat on the > table with the M100/102 connector pins up (as it would be when installed in > the M100/102), pin 1 on the M100/102 is pin 1 on the DVI. Pin 20 on the > M100/102 is pin 20 on the DVI. And so on. > > Jerry > > On Mon, Nov 18, 2024 at 7:20 PM Michael Brutman <[email protected]> > wrote: > >> I powered on the M102 first, then the DVI. After the copyright message >> came up I tried the reset button, power off and then power on, and a cold >> start. The machine restarted but the amount of free memory remained the >> same and the DVI disk light did not turn on. I'm fairly certain the DVI is >> not seeing the reset signal from the M102. >> >> Going to BASIC and using SCREEN 1,1 fails because I'm still on the >> built-in BASIC at this point, as DISK BASIC never got moved into the memory >> on the M102. >> >> >> -Mike >> >> >> On Mon, Nov 18, 2024 at 3:20 PM Jerry Davis <[email protected]> wrote: >> >>> After executing the power-on sequence and getting the "Microsoft" >>> message, did you execute the BASIC command "SCREEN 1,1" from the Model 102? >>> >>> The above command switches output to the CRT on the DVI and displays the >>> key labels at the bottom of the CRT. >>> >>> Jerry >>> >>> >>> >>> On Mon, Nov 18, 2024 at 11:39 AM Michael Brutman <[email protected]> >>> wrote: >>> >>>> I've tried all three methods - power off/power on, Reset, and cold >>>> start. There is no difference. Also, the two machines have no options or >>>> expansions that would alter their behavior. >>>> >>>> The technical service manual has a reasonable troubleshooting guide >>>> which gives specific pins and behaviors to look at. I'd still like to find >>>> a known good cable before breaking out an oscilloscope, but at least the >>>> schematics and behaviors are documented. >>>> >>>> The length of the cable is kind of freaking me out a little bit - for a >>>> bus that's a long stretch. Do you know the length of the original factory >>>> cable? >>>> >>>> >>>> -Mike >>>> >>>> >>>> On Mon, Nov 18, 2024 at 9:19 AM Royce Taft <[email protected]> wrote: >>>> >>>>> One other thing you could try is a cold start (CTRL+PAUSE+RESET). It >>>>> will wipe all your 102’s memory, but maybe it will help? >>>>> >>>>> Royce >>>>> >>>>> Sent from my iPhone >>>>> >>>>> On Nov 18, 2024, at 08:34, Michael Brutman <[email protected]> >>>>> wrote: >>>>> >>>>> >>>>> I had checked the connectors and pins before I wrote, and I was even >>>>> going to check for continuity on each pin but that's going to take a while >>>>> and be error prone with 40 pins. The connector on the underside of the >>>>> DVI >>>>> has the snap-in latches which are engaging. I can't push any further and >>>>> I >>>>> haven't bent any pins. The cable is new from Gregory (Arcade Shopper), so >>>>> I don't have a lot of reason to suspect it. >>>>> >>>>> Besides trying two different 102s I've also tried batteries and wall >>>>> power for the 102s, and I even upgraded one to max out the RAM just in >>>>> case >>>>> I was missing a memory requirement. >>>>> >>>>> The DVI unit itself was pristine on the inside when I first looked at >>>>> it. I'll have another peek inside to check the connector; perhaps it >>>>> experienced some trauma and there are broken traces on it. But I really >>>>> don't want to look for problems where they are unlikely or fix things that >>>>> are not broken .. I've learned that every time I disturb something there >>>>> is risk involved. >>>>> >>>>> Is there anybody in the Seattle area (northern suburbs) with a known >>>>> good cable? If I can eliminate the cable as a possibility then there is >>>>> only the DVI connector, as the rest of it seems to function normally. >>>>> >>>>> >>>>> -Mike >>>>> >>>>> >>>>> On Mon, Nov 18, 2024 at 7:10 AM Royce Taft <[email protected]> >>>>> wrote: >>>>> >>>>>> When I had this issue, it turns out I hadn’t snapped the connector in >>>>>> fully on the underside of my M100. I would disconnect it and ensure no >>>>>> pins >>>>>> became bent and flattened out. If the pins look good, carefully replace >>>>>> the >>>>>> connector and snap it firmly into place. >>>>>> >>>>>> When making my cable, to figure out the location of pin 1 on the M100 >>>>>> and the DVI, I think I used a multimeter and the pin outs in the various >>>>>> manuals to look for ground pins which gave some insight into the >>>>>> orientation of the connectors. >>>>>> >>>>>> Seeing “please wait” followed by a Microsoft copyright is a very good >>>>>> sign that your boot disk was successfully read. >>>>>> >>>>>> Royce >>>>>> >>>>>> Sent from my iPhone >>>>>> >>>>>> > On Nov 17, 2024, at 21:20, Michael Brutman <[email protected]> >>>>>> wrote: >>>>>> > >>>>>> > >>>>>> > Ok, here is the part I hate ... getting things put together and >>>>>> then not having it work. >>>>>> > >>>>>> > I'm using Greg's cable kit with a Tandy 102. I have the twist >>>>>> adapter on the 102 side, red stripe oriented as in the pictures on the >>>>>> Wiki. (The red stripe closer to the 'S' of "System bus".) That goes >>>>>> into >>>>>> the IDE ribbon cable, which is connected to the DVI also using the >>>>>> orientation in the pictures from the Wiki. >>>>>> > >>>>>> > I used Teledisk to create the disk image. I powered on the 102 >>>>>> first, as per the DVI user manual. When I power on the DVI I get the >>>>>> "Please wait!" message, and then I get the Microsoft copyright message. >>>>>> All of this is good so far. >>>>>> > >>>>>> > Where things fail is when I try to load disk BASIC onto the 102. >>>>>> The instructions say to use the Reset button or to power the machine on >>>>>> and >>>>>> off. Neither has any effect, and I've tried it with two different 102s. >>>>>> > >>>>>> > What am I missing here? >>>>>> > >>>>>> >>>>>
