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retroclouds

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Posts posted by retroclouds

  1. Posted

    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.

  2. Posted

    Well, the PEB PS will need to fixed or replaced, and in the process of trying another P-box, I had my SAMs card blow a couple chips, it was regulated so, it must have been feeding on the ground plain or somethng, especially the 612 chip. But in that process I saw my SAMS acting like you video, so it begs the question, does your HRD 3000 have the 32k mod on it? that may explain the flicking light.

     

    no, I do not have the 32k mod.

    • Like 1

  3. Posted

    Well the video didn't happen, sorry, on Wednesday night, waiting out the hurricane I was trying to get my HDX, that I had built plugged into the PEB, so I could load the DSR, and try it out. It is tigt in that bow and I didn't see that an aluminum brcket that was mounted to the RS232 was bending in while I was plugging it in. The result took out a couple of components as well as the PEB. It still powers but it will not light up any cards, though those same cards plugged into another PEB do light. My PEBs have been stored a long time and I have to work out bugs. I do have a switched PS in one and will jumper regs to see if I can video this for you, over the weekend.

     

    Have you tried running Megtest on it? With the HRD814F disk you auto load with XB, then click on the 3rd item on the list and go into megtest then it will ask you how many 32k chips you have, common HR 3000 Ramdisks usually have 12 and if you are using 128k chips, they each = (4) 32kchips. If you don't get the this far check the transistors first. I think there are two on the 3000, but would have to look at the construction manual. Also, I don't have any knowledge of CFG834, have only used 814F, but you might try the config option, # 1 on the menu and see if it show the cards cru address, if not this would also point to a hardware issue, such as a bad switch.

     

    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 ?

  4. Posted

    Now one other thing that you might try is using another switch.If it's doing the same thing in either position, the switch might be non-functional, have seen it happen. Meanwhile I will get a video tonight.

     

    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.

  5. Posted

    Yes I can take a small video. But I do have one question, switch 1 is cru 1000, do you have any conflicting cards with that cru?

     

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

  6. Posted · Edited by retroclouds

    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.

  8. Posted · Edited by retroclouds

    Well, last night I finally found that the 8k dsr sram chip had 17 errors show up on the U11 test, this would explain the locking up condition. After I swapped the sram with the one from the Horizon 3000 board, the 4000 works, but needs battery work and the 3000 works, but needs a new 8k sram. One of my, I guess '2000' series, works, but needs a new CRU switch and battery holder work. Progress is being made, one diode at time.

     

    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.

     

    post-16219-0-10413900-1538627889_thumb.png

  9. Posted

     

    ..

    It may not be unreasonable to expect no better performance in Pascal on the 99/8 versus the 99/4A. As I understand it, booting into the p-system is effectively bypassing the TI CPU in favor of the p-system. If that is true, the faster 9995 would be of no benefit except for assembly language routines.

    ..

     

    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?

    • Like 1

  10. Posted

    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.

  12. Posted

    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).

  23. Posted

     

    Usable and executable, but not editable by standard means. IIRC, I used an XB utility called Super Extended BASIC to remove line 0. I still have the joystick cable dongle for that program somewhere in my parts bin.

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

  24. Posted

    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.

    • Like 1

  25. Posted

    Hi people,

     

    today I bought a Tomy Pyuuta Tutor (japanese version) for cheap (118 USD including shipping)

    Normally they are a lot more expensive, I've been watching ebay for more than a year now.

     

    The idea is to tinker with it and I would at least like to see my Pitfall version running on it ;-)

     

    So the question is, can someone point me to the direction where I can get a homebrew cartridge board?

     

    Also does anyone know, if it would be possible to turn a japanese Tutor into the american version by swapping ROM's ?

    Ofcourse would be great if I can swap keyboard too, but I guess that won't be so easy.

     

    Also have been wondering; what is the TI machine that comes closest to the Tutor? Would that be the TI-99/4a, TI-99/5 or TI-99/8 ? :grin:

     

    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.

     

    post-16219-0-71942400-1530821851_thumb.jpg

    post-16219-0-16541000-1530821926_thumb.jpg

    • Like 3
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