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rmzalbar

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About rmzalbar

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  1. I do have my limits: I will leave the cardboard shield out of a breadbin C64 so those hot chips will live longer; however, I always at least replace the bottom shield since these old PCBs lack even a ground fill. I'll try those pokes next time I have the 1200XL up on the desk. I can definitely confirm the faint herringbone is not my imagination, though I don't notice it unless it crosses my mind and I look for it. I finally ordered a DS1054Z today after having been without a scope for several months (I was only borrowing one, I never owned one.) So pretty soon I'll get down and dirty with some ceramic capacitors and see what I can do about it.
  2. I doubt the saturation boost would do anything in the black areas of the screen like that. I believe all it does is crush the colorburst reference on the front porch during hsync, which shouldn't cause anything to appear in the black areas of the screen. Any noise leaking into the composite signal from elsewhere in the Atari that raises the level up from black might cause it to look like that in the darker areas of the screen. You can see that the noise covers the entire screen and seems to have patterning that changes in different areas of the screen. I'm not clear on which areas of the screen are not addressable by the display on an Atari (borders of the screen?) but if the noise is visible in such areas, it wouldn't be a logic problem (like video ram.) The patterning suggests that digital noise from other operations is leaking into the video signal, either from failing digital componnts (GTIA, transistors, diodes) filtering components (capacitors) or poor grounding somewhere.
  3. Is this why I usually see a yellow screen during a power-on or reset of my 1200? It doesn't appear to have any ill effects.
  4. No. In the photo, the Traco is not attached to the heatsink. I left the heatsink there for the benefit of the rectifier.
  5. I would like to cap this off by saying that I did contact Lance, and he was very helpful. We had some issues with USPS delivering to the wrong address and slowing things down, but ultimately, he was able to provide me with a Venture cart that works! I'm completely satisfied now.
  6. I was mistaken when I said the Vic-II handles RF generation. That's not true of course, it generates Luma and Chroma.
  7. There is a similar project for the C64 called VicII², and indeed, it has every single one of the problems you are listing here. To get around all of the issues, they had to go with relays instead of solid state logic (in part so the power is switched) and a side-by-side board as opposed to a stack; and even with the side-by-side layout, the need for heatsinks on the ICs means that it will only fit in the taller breadbin-style models that have enough space under the keyboard. Perifractic has a great video on how they developed it and dealt with each of the challenges that is worth a look as there are a lot of parallels there. The end result was a brute-force approach that turned out to be physically imposing and pretty expensive. And, of course, for North Americans we need a monitor capable of full PAL decoding, not just 50hz capable as the case would be with the Antix. I have one in just one of my breadbins and I really like having the convenience of it, but it was a little finicky to get going. Crucially, the Vic-II also handles direct RF generation, so switching and tuning the clock generator and switching the RF output also had to be done which isn't really the case with the Antic since some of those functions are on GTIA. Given the expense and limitations, I could see where an FPGA Antic implementation could be the right drop-in solution in this case.
  8. Nice, thank you for coming back to post the solution.
  9. Hi Everyone. A lot has happened in the thread since I posted my issue. I thank everyone who is concerned on my behalf; paying a retail price for a cartridge game and finding out it isn't quite ready go isn't an optimal experience. Coming here and seeing that the author has stated it would be fixed is concerning because, while I didn't see this thread beforehand, someone else who did would have been making a buy decision with false information. Regarding dumping and sharing - Yes, certainly when I was younger I pirated the heck out of games, but I'm not the same person I was when I was a kid. I evaluate things differently now. I care about the health of the community and the fortunes of others, even those who aren't perfect, and being trustable is important to me as well. So I have formed principles based on that, and they don't change even if the author's behavior is not perfect. I see that as an issue to handle separately, it is not for me to mete justice in that way. I did send an email to Lance, and he is providing support. I'll let you guys now how it works out. Thank you!
  10. It looks like a common issue with the 6-switcher models using the 4050 to buffer the firebuttons. The reason 4050 is set to 3.6 volts must be to set the video levels, which is mostly what that chip is concerned with. The firebutton doesn't need to be level shifted, though. A few people "fixed" it by bypassing the 4050 with the firebutton lines (which is fine, as the 4-switch models did simply that.) Why is 3.6v not good enough to prevent firing in the first place? Not sure, but possibly an aging TIA chip or still a marginal 4050 or socket. Here's the thread on the issue:
  11. Oh, crap. The 4050 gets its power from a voltage divider composed of resistors R231 and R232, with a result of 3.6 volts. So that is normal. I'm sorry I didn't check this earlier. So it looks like the purpose is to intentionally level-shift the 4050's output to TIA to a range of 0v - 3.6v. I'll think about this a bit more..
  12. Hi! Yesterday I bought 4 separate items (all of them carts,) but at checkout I sent an invoice request for combined shipping. That request is still pending, but today eBay is auto-warning me to pay to avoid an unpaid item claim. If you can't do combined shipping, please let me know. Thank you.
  13. I really went to get Xenophobe, and added this to my order on a whim because I've always liked Venture. If I seen this thread before buying, I probably still would have made the purchase because the last couple pages seem to indicate that the bug was fixed for all future cart orders. Putting the bug aside, the game is good, graphics are colorful, controls are easy, and I like the addition of music. I do find it to be on the easy side compared to arcade Venture (will playtest MAME real quick to confirm.) I will drop a note to Video61 to see what they say about the fixed version supposed to be available.
  14. Floating pin 9: Pin 9 is the trigger line coming from the joystick port, which is always fed +5 volts from a pullup resistor. It should be near 5v when firebutton is not pressed. 4.8-4.9 is fine (there will always be some losses, which is why you'll not see the full 5v anywhere distant from the power supply). It shouldn't be "floating" as it should be actively fed 5v through a resistor, which you can see on your schematic. Do you mean that the value drifts around? Make sure you have a firm connection with your probes. You can confirm presence of ~5v at this pin with 4050 unplugged. 3.5 - 3.6 volts on pins 6 and 10: The 4050 should be capable of feeding enough current to raise the outputs to close to the input, i.e. it should be near 5v when 7 and 9 are 5v. These lines go straight to the TIA. A multimeter adds some parasitic load (a few milliamp) and some capacitance. This can only matter if the circuit is not actively fed or drained, so leakage currents cause the voltage to passively float up to some level, easily drained away by your multimeter. However, the output of the 4050 can only be at +5v or ground, so there can be no float on the outputs while that chip is powered up and functional. Again its looking like the 4050 isn't strongly pulling the output circuit high or low. Check the socket for good contact on all pins. You should be getting a strong +5v power supply to the 4050 on pin 1, and a good ground on pin 8. You can prove the TIA is working by jumping +5 volts over to pin 10. Firing should stop immediately. Its trigger point, by the way, should not be anywhere near 4.9v, it should be much lower. I can't find a spec on the TIA logic levels, but the trigger point should be somewhere between 0 and 5v, but closer to the middle than near one of the extremes.
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