Jump to content

mytek

+AtariAge Subscriber
  • Posts

    6,538
  • Joined

  • Last visited

  • Days Won

    30

mytek last won the day on October 14 2021

mytek had the most liked content!

About mytek

  • Birthday 02/28/1956

Contact / Social Media

Profile Information

  • Custom Status
    Releasing Magic Smoke
  • Gender
    Male
  • Location
    Santa Rosa, CA
  • Interests
    Electronics, Computers, Cryogenics, Embedded System Design

Recent Profile Visitors

21,251 profile views

mytek's Achievements

Quadrunner

Quadrunner (9/9)

10.6k

Reputation

  1. I got my boards from JLCPCB, and got one set built for my Long Board 250407 motherboard. I built it so that it could use an 8562R4 HMOS VIC-II chip instead of the original NMOS (it's fairly easy to configure it for this). Gives a nice picture on my 55" HDMI monitor using a cheap S-Video to HDMI converter. And does a good job outputting Composite video as well (that top to bottom gradient doesn't exist in reality, just a side effect of the camera). I used one of these to break-out the audio and composite video. White = Audio Red = Composite Video This is also configurable giving you a choice of signals on the right channel (red) output: Right channel Audio with Stereo SID, Mono to both channels, Composite video, or LumaCode (if you have the Digitizer).
  2. That does kinda look like what I saw when running my experiments using an AHCT chip, but I can't say with certainty that is what's happening on your end. In the 576NUC+ I used a 74AHCT14 and didn't see any issues with using it as the oscillator stage. For all I know it might have looked like your waveform, but if it did the over/under shoot wasn't a problem for GTIA.
  3. Well at the time I was really looking for a no-change drop-in replacement for the 74LS08 that would improve things. But I wasn't adverse to having to add parts if needed. However when I discovered that the 74F08 would do the trick on its own without creating big under and/or over shoot spikes I was sold, and got my drop-in replacement - no resistor needed. Correction: In the beginning I was really looking at the need for any buffering, but after discovering that it was necessary, settled on the 74F08. Later still in the 576NUC+ since I also needed a few inverters for other parts of the logic this got changed to a 74F04 chip, with a couple of it's gates back-to-back for the buffering. For some reason on that same system I went with a 74AHCT14 for the crystal oscillator and CSYNC buffering instead of a standard speed HCT part (might have been a problem sourcing an SOIC version at the time).
  4. Since a 74F14 is still a Schmitt Trigger inverter, albeit a TTL output type, it will have similar characteristics when used in an oscillator circuit but simply not go to the full positive output as an HC equivalent part. However I wouldn't think this would be a problem for the GTIA oscillator input pin since that works fine with the original 2 transistor oscillator circuit which also can't switch to the full +5V rail either. But this is all conjecture on my part, and this is about your board design, not mine, so you get to call the shots based on your experience with it. On a side note, if the reset circuit is based on an RC delay, I would also think the 74F14 would be OK for that as well, once again because it's Schmitt Trigger in nature and the NMOS chips that need it work fine with TTL level outputs. Since my curiosity is now peaked, I will have to do some tests later today to verify for my own satisfaction and future reference. EDIT: Hold your horses. This likely does not need to be high speed for your specific application. I've used 74HC14 chips for the same thing in the past (1088XLD), and most likely a 74HCT14 would also work, especially since you originally spec'ed a higher speed version of that without incident.
  5. Just my 2 cents... When I did some evaluations of alternatives for the 74LS08 many years ago, I discovered that AHCT was indeed too fast, causing severe under and over shoot (aka: noise). This could be tempered with an inline resistor, but that was more like a band-aid. Whereas the standard HCT part was actually slower than the LS part previously in play. Hence the reason I settled upon using a 74F08 instead, which was faster than the LS or HCT equivalents, but not so fast to cause other issues. EDIT: for the particular use case being talked about in this thread, a 74F14 would be my suggested replacement for U19.
  6. No worries. You're new here and it can take a while to navigate all the topics and forums, plus understand how things work. You should have seen me the first few weeks after I joined AtariAge
  7. Curious as to why Lotharek chose to do this. Presumably to keep the AKI from dislodging from the motherboard. However I've found the Atari supplied sockets to grip very tightly to the machine pins on other upgrades that use a similar set-up (e.g., UGV and TK-II-PBJ). Perhaps there is a variation on the sockets that Atari used, and in some cases the grip is less adequate. In all cases if one replaces the stock socket with a high quality machine pin one, the grip is almost too good, making it difficult to remove the upgrade after installation without the chance of bending and/or breaking off pins. But assuming the upgrade works as intended this shouldn't be an issue, since there would be very little reason to remove it.
  8. This reminds me of trying to save money on such sockets and buying a bin full from a Chinese source for pennies on the dollar, thinking I was getting a great deal. as it turned out they quickly became useless after only 2-3 insertions exhibiting the same problem you are seeing. As the saying goes... "you get what you pay for". Now days I stick to buying these primarily from a reputable source such as Digi-Key or Mouser. And since you presumably got the AKI with the included socket from @lotharek I've tagged him in this post. I've found both of these to be very reliable after repeated insertions, and they are sold at a reasonable price... Digi-Key P/N: ED3032-ND Mouser P/N: 575-1104764041001000 EDIT: I just re-read your post and apparently it is the extra solder that was put on the AKI pins that caused the issue.
  9. Welcome to the AtariAge forums However your first posts have definitely been made in the wrong topic. This topic is about a non-Atari produced product called the 576NUC+ (a fan based production), and not about the 800XLF. I would suggest you open a separate topic to discuss your unit and the issues it apparently has. After doing that, I would request that @Albert or some other moderator move your posts to that new topic.
  10. With all the recent swapping of the Atari's 74LS08 for a 74F08, and the introduction of the Phi2 Fixer board based upon this chip - all in an effort to improve stability, I remembered doing an in-depth study of this back in 2017. That led me to this topic which came out of research being done during the development of the 1088XEL where minimization of components was key, and specifically the necessity of the 74LS08 was the focus at that time. So here's a BUMP in case anyone is interested in where the use of the 74F08 really started to take hold as a substitute for the original 74LS08, and some of the other possible alternatives that led up to choosing it in the end. By far the 74F08 substitution turned out to be as simple as it gets to fix many a problem with modern upgrades in our old Atari systems.
  11. Once again a failure in my communication. Although probably not the best way of saying it, what I meant was that the demo appeared to only let one mouse around (very well in indeed), click on a few menu items with some allowing drop-down selections, and able to open multiple active task managers and/or text boxes plus move those windows around. This was all very impressive, and is what enticed me to create a PS/2 mouse aspect in the 1088 series systems I designed, thinking to future proof those systems so to speak. However it was far from a working desktop with the conspicuous missing file manager window. So in other words no non built-in applications could be launched, and what was built-in was very minimal from a usability point of view. The missing file manager was what I specifically meant by no underpinnings (e.g., a set of ideas, motives, or devices that justify or form the basis for something). Without a working file manager there really isn't a whole lot one can do with the GUI, so to me that meant it lacked a practical basis at this time, no matter the possible future potential. Like I said perhaps underpinnings was a poor choice of words on my part. Now I think I'll shut up before I really get in trouble 🤪
  12. I didn't regard that as the least bit ambiguous, but if it was, I apologise and thank you for clarifying. Well to be clear let me re-post the full context where that was snipped out of... As can be seen I wasn't saying that Open Source was the only way this could get done. Instead what I was trying to say is that if you weren't able to get to it due to other obligations -AND- what you had accomplished thus far wasn't Open Sourced, that the chances were 'bleak' that it would ever see completion. Seems pretty logical to me, and wasn't the least bit derogatory about your abilities, unless you consider yourself to be Superman and like him can execute multiple things at light speed without ever needing to take a break. BTW, although English is my first and only language, I will be the first to openly admit that I butcher it quite frequently, and many times people misunderstand my intent. I'm sure that almost anyone better versed than I, such as yourself could have done a far better job of conveying what I meant to express (thank goodness I'm a subscriber and can re-edit my posts, otherwise a lot of it would end up being word salad for sure).
  13. Interesting. Although I made no such insinuation, at least not that the project or said software application would already be done if it were open sourced. I merely implied that in the present scenario with only you being privy to the details of the actual code, and the ongoing necessity to focus your talents elsewhere in order to make a living, that it hadn't seen much 'shared' progress as in any new demo releases that I was aware of. Although you did mention work that had come out of the SIDE3 project being applicable to the GUI, this was not apparent until your mention of it yesterday. And just so we are all perfectly clear, nothing I posted was meant to disparage the GUI project or yourself in any way, or to suggest your best course of action on getting it done. It was simply an observation that other things and life in general had seemingly side tracked the project for the last several years, and that perhaps open sourcing it might have had some positive affect on this, but apparently that assumption was of a 'specious' nature (I had to look that word up to know what it meant). The written word on forums can conjure up so much confusion and/or misunderstanding if one is not extremely precise in what is written, which in itself can become tedious in nature. Now I wish for that time machine so that I could go back and stop myself from running this topic off course 🙄 No reply necessary. Time to let the discussion get back to where it was before my interruption.
  14. I didn't see any hornets nests coming out of what you posted, or for that matter what I posted. But I guess everyone has a unique way of looking at things.
  15. I had to chuckle when I read this Although the demo that's been out there for many years looks very enticing, it is after all just a proof of concept with no underpinnings. Essentially just window dressing at this stage. However it was so convincing at the time I first saw it, and the potential was there for it to become something truly usable and great, that I even worked on the hardware side of things to bring a PS/2 mouse aspect into some of my creations starting in 2017. After 14 years since this topic first got posted, and not much traction over the last half of that, chances are looking bleak that this will ever see fruition as a completed workable GUI desktop application. And probably due to it being closed source pretty much insures that to be the case (the only guy working on it has gotta make a living doing other things). Don't get me wrong... What Jon accomplished in the demo looks absolutely incredible! However for anyone to hold out hope for something more beyond what the demo currently does, is in my opinion wishful thinking, which is something I was guilty of for many years myself
×
×
  • Create New...