retroclouds

Nice project! I like it very much. If memory serves me well you cant run assembly language from 32k memory expansion while speech is playing. That is why you have to put the speech playercode in scratch pad memory in the console. Wonder if the same apllies here.

no, I do not have the 32k mod.

Hope your PEB and cards are ok doing well. As far as my HRD is concerned, did some measurements with my multimeter on the diodes and I believe to have an issue with both CR4 and CR5. I repeated my measurements multiple times to be sure. CR4 and CR5 seem to be conducting in both ways. Also checked CR6, CR7, CR3, CR8, CR9; no issues there. On whtech I found the horizon 3000 construction guide. At some point it says: We have found the germanium diodes CR4-CR7 can be the problem. The diodes can be replaced with Radio Shack Cat. No. 276-1123 So my question is, what is a good replacement for these germanium diodes in 2018 ?

I tested the switch with my multimeter and it's looking ok so far. Don't expecting any issues there. Did order a few switches as this one is not in a so good condition, waiting for these to arrive, just to be safe.

No, no conflicting cards. Also tried removing all cards except 32K and Disk Controller, no difference. Tried different CRU's already, no difference.

RickyDean, would you mind taking a short video of the Horizon Ramdisk 3000 in action? In particular I'm interested in seeing when the the LED located at CR1 is on and when it is off. I have a still non-working HRD 3000. The behaviour I'm seeing is that the CR1 LED flickers in irregular intervals as soon as I boot up the TI-99/4a, which I don't think should be happening. If the switch in location SW1 is turned off, the TI-99/4A works as expected and there is no conflict with the Disk Controller, but ofcourse CFG834 doesn't recognize the HRD. By now I have replaced the following components U24 - SN74LS245N Motorolla I8514B ok U23 - 74LS244 PC F 8534 KOREA ok U22 - 74LS244 PC F 8534 KOREA ok U21 - SN74LS156N Motorolla I8543 ok U20 - SN74LS138N Motorolla I8049 ok U19 - SN74LS138N Motorolla I8049 ok U18 - SN74LS138N Motorolla I8049 ok U11 - JAPAN 8703 HM6264LP-12 U0422YY0 ok U10 - SN74LS259N Motorolla FFXG8945 ok U9 - SN74LS259N Motorolla FFXG8945 ok U2A - AD +B9024 G MM74HC154N ok U1 - SN74LS138N Motorolla I8049 ok After replacing these components, the card still doesn't work. Only difference being that the TI-99/4a no longer locks up on boot up. It does lock up while loading anything from disk drive 1 (e.g. CFG834). So by now I wonder if there is some electrical leakage that messes with one of the busses causing CR1 to flicker like a christmas tree. EDIT: The HRD 3000 is in slot 4.

I read on Thierry's page, that there are 2 utilities available for testing the HRD after building. They are called MEMTEST and MEGTESTare these available somewhere ?

Can you elaborate on how you tested the 8k dsr sram chip? I obtained a HRD 3000 and it immediately locks up on the title screen. Already did multiple tests and this leads me to believe, either the sram or one of the logic chips has died Batteries are ok, tested outside and when installed in the ramdisk as well- dip-switch settings checked and ok as well. If I do manage to get pass the title screen and run CFG834, it either locks up or shows bogus information. I've now gone so far to get new logic chips and an SRAM so I can replace one by one if required.

I was under the impression that the p-system is a pure software solution on hardware (peripheral card on the TI-99/4a, onboard on the TI-99/8), with the p-code (virtual) machine running on the TI CPU. Or am I missing something?

Very cool. Like the idea of combining cart and SAMS. Ive been toying around with the idea of doing something similar. My idea is to go for the first revision of Minix, as it matches hardware of that time. This is more of a personal project as I like to learn more on OS concepts and dont have any code developed at this time. Particular interesting is how you would handle preemption. For my minix project I was thinking about a small sidecart board that has software controlled HW timers that generate load interrupts. As said only ideas floating around in my mind. Good luck with the project! I am very interested seeing how this further evolves.

This is the second one he has up for sale.I got the first one last week and am looking forward to its arrival. Also got the gramulator card. For me this year is the best year for getting TI and Tutor gear so far, so very pleased with that. If only I could find more time to play with it :-)

Indeed, the file C99_in_PC99_format.zip went missing. This probably happened while moving to my new provider. Checked my backups so far, but was not able to find it. Before I do a lot more digging in my old backups; if anyone has downloaded the ZIP file before and has it at hand, then please send it to me so I can upload it again. Thx. By the way, http://aa.ti994a.oratronik.de is not a website really. It's just a container for holding files, so you have to know the exact path (as referenced in the Development Resources thread).

Thanks for the hint. Will check what went wrong there.

I will check what went wrong there

ok, have to ask this; what does autocomplete mode do?

I read about that. What was TI thinking not to carry the LOAD line.

The idea is to have a software timer on PI side that periodically triggers the load interrupt. That way preemption could be implemented with a higher rate as the 60 times a second for a VDP interrupt.

Hi, just wondering. Is there a possibility to trigger a load interrupt via software on the TIPI ?

Are the physical paths the same as well? I mean would it take a lot of effort to for example turn Ralphs final rom cartridge in a tutor compatible version?

I would definitely go for SAMS support. Quite sure that when the hardware is there Software will follow.

Reminder for myself that I should add CAMEL99 Forth. https://github.com/bfox9900/CAMEL99-V2

Do I understand correctly that there is a Pitfall 2 port available for the Tutor?If yes, are there any videos or pictures available?

Joystick cable dongle? Can you give some details on that. Would be interesting to know how the protection was implemented.

Could you not have some kind of custom breakout box outside the console/computer that you could use for splitting the audio signal and which has the hdmi/dvi/vga or whatever is dediced for. That way you could have your own protocol into the breakout box and go from there. I know this does not solve all issues. Sure, it would increase costs but it would open some possibilities without having to do a major redesign. Could even have the possibility to add hdmi at a later stage.

ok, people so a while a back I got the Tutor delivered from Japan. This is a though one, got it on ebay real cheap compared to the prices you normally see. The thing is, it's in such a good condition. The operator manual looks brand new and I'm pretty sure the unit was never (or barely) used at all. Joysticks are in pristine condition too. This makes it hard for me to tinker with it. Anyway I'm still in the process of getting a voltage step-up regulator so that I can run it in Europe. Here's some pictures. Oh, and big thanks to @tanam for his great gifts. Really looking forward to play with these.