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sm3

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Posts posted by sm3

  1. Posted

    Another thing you can try is starting it up in 64 mode. Hold the Commodore key on power on. Sams Computerfacts has troubleshooting info for no video, but it requires a multimeter and o-scope.

     

    You may want to look here and download some repair manuals:

     

    http://www.bombjack.org/commodore/books-commodore128.htm

     

    Unfortunately the 128 is more complicated than the 64 for repair work since it's 3 computers in one. The Z80 CPU in the 128 is actually part of the power up sequence so if it's bad, you'll get nothing out of it. But it's odd you would have 3 128's with the same issue.

     

    I know on a 64 bad RAM will cause a black screen. You can usually test for that using a cartridge like radar rat race that bypasses the RAM. Any Ultimax mode cartridge will do.

     

    If you use a 64/128 a lot, you can always invest in a dead test cartridge and also a diagnostic harness/cartridge. This helps with troubleshooting issues (including no video (w/ dead test cartridge) ) greatly.

     

    From Sams Computerfact for the 128:

     

    "No video when using the RF modulator. Use a scope to check for a video waveform at pin 17 of IC U21 (this is the VIC). If the waveform is missing at pin 17 of IC U21, check IC U21 by substitution."

     

    Looks like you've posted about this on lemon64.com too. Seems we should try our efforts on one site instead of 3.

  2. Posted

    There is also the emulators and development tools by Matthew Reed: http://www.trs-80emulators.com/#DevelopmentTools

     

    While there is no IDE for it like Eclipse, you can just use your favorite text editor or something to build your source. Only the registered version allows you to interact directly with virtual disk files, however, his TRStools software allows you to insert files, create virtual disks etc.. so the limitation isn't that bad to me. I went ahead and licensed my copy though. I wanted to encourage him to continue to make and support this software.

     

    www.trs-80emulators.com/

  3. Posted

    Hi, I'm glad you were able to get your Model III working 100%, that is great news!

     

    I'm sure you've seen these 2 items, but I'll share them here anyway. I'll say up front, these are not super cheap.

     

    First, there is the FreHD: http://ianmav.customer.netspace.net.au/trs80/emulator

     

    For FreHD, Ian sends along 2 (1 for boot 1 for backup) floppies that you boot from to start up the FreHD and then once it boots, you can remove the disk from the real drive. He sells (or you can burn your own) a ROM that will allow you to boot without a floppy, but I have no experience with that. You can place disk images from the internet onto the SD card and copy them back to real floppies.

     

    Second, there is the M3SE http://bartlettlabs.com/

    The creator of this item sells them on eBay along with the Model 1 version (MISE) http://www.ebay.com/itm/222018785069 (you may be able to get a few bucks off if you buy direct from the seller outside of eBay)

     

    I don't have the Model III/4 version, so I can't speak about that, but the Model 1 version boots without a real floppy in the drive and then you can also copy disks back to the real floppy drives if you wish.

     

    Maybe someone else can recommend cheaper options.

  5. Posted

    Great! I really hope you can get it working again. I have a Model 4 myself, but I really love the look of the III and 4.

     

    Just remember to be very careful when you pull the case apart so you don't catch the back of the picture tube on the housing for the PCBs. But sounds like you have already pulled yours off, so you are probably aware of that.

     

    I think the older Model IIIs came with 2 power supplies if they had the disk drives, but I don't claim to be a TRS-80 expert.

     

    Good luck.

    • Like 1

  7. Posted

     

    Are you on firmware version 3.0 or 2.6. I'm trying to do some research and I've found some sources saying 3.0 breaks JDos. I also can't seem to find any specific instructions on how to roll the firmware back to 2.6. If you guys know how, please let me know.

     

    Yeah, I'm still on the 2.6 series. I haven't tried the beta versions of 3.x yet.

    • Like 1

  8. Posted

    Hey Larry, well, I personally like and use the XRGB-mini Framemeister. But it's a little pricey, we are talking over $320 US. It even allows you to add scanlines ;)

     

    I don't use it daily though since I still have working CRTs, it was mainly to use when the CRTs fail. It can even do RGB with the right connectors.

     

    Here is one on Amazon.com: http://www.amazon.com/DP3913547-Framemeister-Micomsoft-Upscaler-Japan/dp/B00QUBK6RK/

  10. Posted

    There's absolutely no way I could choose two Model I/III games; I used a TRS-80 every single day for 10 years and there's a ton of great games.

     

    Starting with a Level I, 4K system I played Flying Saucers, Tandy Invaders and Time Trek to death!

     

    Of course every Big Five Software title written by Bill & Jeff was top notch! Computer Shack/Michtron rarely put a foot wrong either, even if 3 of their later games were essentially the same game. Time Bandit was a stand-out from them. Ditto for Adventure International; Eliminator and Donkey Kong examples from them. I especially liked Penetrator, it was an amazing Scramble clone given the capabilities of the machine. Funsoft had Apple Panic. Fun Division had Donut Dilemma. Acorn had several... there's dozens I can't recall now...

     

    Cool, I didn't know about "Penetrator" until now. It looks pretty nice! I'll have to download it for my real TRS-80. My time with the TRS-80 was mostly about BASIC programming and had very little exposure to games on it. If I remember correctly, we only had "Cosmic Fighter" on tape in my school.

    • Like 1

  13. Posted

    Hi 1050, well, you certainly have a better grasp of what is going on than me. As far as room, there isn't much room between this board and the next RAM module really. The chips ride pretty high when they are inserted into the PCB.

     

    I'm attaching a picture of the back side of the board. The FP math ROM is the 3rd from the right side (looking at the back).

     

    At this point, if it's going to take a lot of jumper wires or modifications, I really don't think it's worth the effort to me though. The board works now as it is with OSN, the Stock Atari FP math package and Omnimon. That really is good enough for me.

     

     

     

    post-35256-0-92680800-1441308269_thumb.jpg

  19. Posted

    My CMOS 27C16's came in today, I programmed them with the FastChip.rom and still nothing! When I use the stock FP ROM, everything works as is expected though.

     

    While searching for information on the Fast Chip I read a thread stating that the math package is a custom masked ROM. So I guess there is no use in attempting to swap an eprom for it. The stock OS math package is probably that same custom mask ROM.

     

    I don't know. I will quite while I'm ahead. At least I have OSN now and Omnimon on my 800. I will just buy an OSNXL from B&C and put it into my 800XL ;) At least then I know I have all 3, OSN, FastChip and Omnimon.

  20. Posted

    Hi Larry, thanks for the tip! I can't say I really looked at the legs on them before I attempted the programming. I did order a batch of CMOS 27C16s as well so maybe the 2 NMOS '77 EPROMs I have are not good.

     

    Since this is the first time I've ever tried to do this, I was super excited when I found that the OmniMon worked as expected ;)

  21. Posted

    Yeah, OSN is the Newell RAMROD OS. I didn't try the FastChip rom using the stock OS ROMs, so I can give that a shot. It could be possible both of my 2716s (I only have 2) are bad. They are dated '77 but it programmed without an issue in this last run. They both are in great looking condition for 1977 EPROMs and are supposed to be NOS.

  22. Posted

    Thanks, yeah, excited to finally get some use from this board!

     

    I played some Pac Man on it with the cartridge from Tep392. This should prove the OSN is working shouldn't it? The lack of the "Atari Computer - Memo Pad" on first power on has me concerned, but it may be normal for OSN.

     

    Doesn't appear to be much information out there on OSN that I can find. I also need to figure out why the FastChip.rom provided by 1050 doesn't work. Maybe I'm doing something wrong with it during programming.

     

    I appreciate the assistance and guidance everyone has provided while I worked my way through this.

  23. Posted

    Fantastic! OmniMon provided by 1050 in this thread works just fine! I used one of the extra 2732 ROMs I had, placed it into the RAMROD and started it by holding OPTION and hitting SYSTEM RESET.

     

    AtariGeezer, I did find a "Blank Check" option and it showed the chip was empty, but then I tried to program it and it still failed. I tried another, and it worked. Go figure.

  24. Posted

    At your eBay link you can click on the devices list and read which adapter is needed for what, plus the breakdown on the 2732 (25+), 2732A (21+), and 2732B (12.7+) chips, so it's a matter of buying 2732B and not buying a 2732 if your programmer doesn't do 25+ volt programming. That device list is quite informative.

     

    So I can cook you up some FastChip rom code, turns out Bob Puff fixed it in his US+ OS release. I never noticed before this moment, but grabbed a segment out of omnimonXL OS and did the same with US+ OS to find one byte difference between the two segments. A little investigation at offset 1E0h shows good (Puff fixed) code is E9h - SBC #$09 and older bad code there is E5h - SBC $09. The first is subtracting an absolute value of nine, the second is subtracting what ever the value that is held at memory location 0009h, otherwise known as the BOOT flag which is usually one. And not too likely that 0009h (BOOT flag) holds anything of value that the math pack needs. Very common late night programming error to make leaving out the # sign, surprised no one said anything before this.

     

    attachicon.gifFastChip.zip

     

    This code goes into a 2716 or similar sized 2K EPROM for the 800 only for life at D800h region. You can overwrite 1800h thru 1FFFh offset region to transplant this code into a standard 16K OS file if you want the Puff fixed Marslett FastChip code there too. I believe this should be called FastChip.rom as our own ClausB has done a better version which most are calling FastMath. Am I right here? Then I see a FastMath posted before ClausB even writes this one so I am confused some to say the least. Where is the source for that one?

     

    http://atariage.com/forums/topic/124761-fast-math-rom/

     

    It won't work on the normal 800 though because it has code residing also in the CC00h region as I understand it. But the normal 800 doesn't use code in that region so it might be made to work after all. A bit out of my comfort zone at the moment, but the linked to somewhere above 800 board appears to be doing just this, but with Omnimon code there which will probably not like being stepped on by FastMath code so we have gained nothing again? Other than maybe getting a clue on how to enable a larger rom in that region for FastMath to live and work all by itself? In the XE/XL this code replaces some international character set and most consider it a good switch out, Omnimon most likely set up shop in that same region on the 800 to make full use of the area so it's not going to want to play well with others as they say. Yet again I'm at a loss for all the Omnimon naming conventions, can't keep one straight with another and still don't know what one does over another similar named offering by the same company. View, 80 and other variants aren't helping my feeble mind to keep things straightened out.

     

    My first attemp with FastChip.rom didn't work. Should I have specified an offset or just let it burn with the defaults? I used a 2716 EPROM for it.

     

    I'm going to try the OmniMon now and see if that works.

  25. Posted

    Your eprom programmer software should have an option to check it...

     

    Ah, OK. I'll have to take a closer look then. I was kind of excited to get cracking on this!

     

    This second attempt seems to have faired much better, no failures this time after the UV erase run.

     

    I've discovered 2 things:

     

    1) OSN doesn't appear to have that "Atari Memo Pad" screen?

     

    2) The FastChip.rom in this thread doesn't seem to work. When I put the stock math ROM on the RAMROD with the 2 OSN ROMs I'm able to use the BASIC cartridge and play Star Raiders. But the math ROM I created, no joy.

     

    Does this mean my OSN ROMs are working? I'm not really sure at this point ;)

     

    One point to note if anyone is going this route, you'll need the external power supply for the GQ-4X to burn the ROMs. The software actually tells you as well when you select the chip type.

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