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    Stargunner

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  1. My input would be to place some ferrite beads on the output leg and glue them on with super glue. Then perhaps place a couple .33 uf chip bypass capacitors to shunt RF signals on both the power to ground planes and output to ground plane. Seems to be areas quite available if you'll scrape a bit with a sharp knife. Don't think this one is radiating EMF too much, that's pure operating loss and while it's always possible, the effective field is well constrained in the inductor design from day one and I don't expect it's being overpowered to any significant degree to cause uncaptured magnetic lines of force to heat my coffee up with. Selecting Decoupling Capacitors for Atmel’s PLDs http://ww1.microchip.com/downloads/en/Appnotes/DOC0484.PDF A decoupling capacitor is also known as a standard bypass cap when you shut off the aggrandizement double speak filter. Why people insist on the buffalo approach as a way to explain something pretty basic is a curse of the ego run amok. At any rate, our Atari are using the glass encapsulated (bodgy/dodgy) .1uf standard unit, commonly marked as 104 (10 and four zeros for 100,000 pico farads) very often and they always were inadequate in the first place. They took a perfectly good chip capacitor and put axial leads on it and then rolled it up inside a glass case such that it looks very much like an old school diode.
  2. Hi Mathy, Yeah, that'll work, thanks. Don't worry about the page layout too much, it's a common thing to need a table top sized document when reading the fine print on these anyway. Not as bad as the 130XE version, but I can only read it in places where I already know what it says, they didn't try very hard did they? Where you been keeping this one at? Is there a story about how you came to be keeping it to yourself all this time?
  3. Thanks for posting that. Well I did miss that one somehow and it's a pleasant surprise to see Matt the rat connected to it from way back in the BBS days. No doubt this one was popular in certain circles. USA high school wrestlers are known by the moniker mat rats and Matt was one of us so he went by the handle Matt the rat. Doesn't sound like it, but it's coming from pure respect in the first place and second, this guy earned his high ranking on the Atari side of things too. So nothing else is wrongly wired that I can pick up on at the moment. It appears that there is no official XEGS version schematic either Atari or Sams which is a pity. It means we are stuck with double guessing on the XEGS. There is somewhat faulty engineering done to the 130XE as to port B pull up resistors (the four on the underside of the PIA(and elsewhere)). They are NOT needed on any of the XLs so why did Atari use them on the XE? Dunno, but in my book it's stupid to use them and just not needed. On par with the SIO "filter" caps that just get cut off all the time. The PIA has pull up resistors inside it on port B, the chip itself has provisions to power on in the high state and then the Atari OS programs port B to also be all high on top of that during boot up. There are no issues to fix here by doing that, so why they did it is beyond me. But my gut feeling is it's way too much, so I would pull those four resistors underneath and ignore the "fix" Atari has done to port B that just isn't needed at all. It is possible that soldering flux in that area might be doing things with those signal levels, so if nothing else please use a toothbrush and some strong IPA on that solder work underneath. The picture provide by Matt's team looks pretty rough in that exact area, which is why I would try it with removed resistors there and all cleaned up with IPA.
  4. https://www.ezsbc.com/product/psu3-5/ https://www.ezsbc.com/product/psu3-12/
  5. Just an early report, but it seems yellow and green from Freddie are backwards at one end or the other. Higher pin count on one chip is the higher pin count on the other and yours has it backwards (high for low)? And also not sure this would make any difference as I haven't looked at that aspect yet at all. Just checking the wiring so far... Where is project main page at? I must have missed this one as I'm going by the photo above and a 130XE sams schematic so far. Confused, never mind.
  6. Thanks for the feedback, well I was half right... That's a new one for me on the HC51 NOT doing as well as the HCT08. Going into my files too. I have to suspect something is special about this one, but since I'm shooting blind anyway, I have no way to know where to look first. Have you tried the selftest memory section and does it show any problems? Any better diagnostic tools at your disposal? I got one of Jurgen's Sys-Check devices somewhere, but I've yet to actually use it. Don't know if it would help anyway either. http://www.van-radecke.de/STUFF/tfhh_HW_info.pdf One of the benefits of having a modern PC run eprom burner is that they often can ID AND check these kinds of logic chips for proper function. Maybe that HC51 is what they call dodgy?
  7. I would have long ago changed out U18 for a 74HCT08 AND gate and since I bought a stick of them and the other one I like to change, U30 for a 74HC51 chip as well. Can't get the latter one anymore so it looks like someone will have to make something functional out of two smd AND gates and a smd NOR gate perhaps? U18 is often enough alone to give it a solid system clock, U30 just added to the RAM stability since it's creating /CAS and /RAS signals.
  8. I remember a short piece from Intel back in the day stating that it would take 7 years of 24 hours sitting in standard office florescent lighting to have any effect. My observation is an encounter with static electricity will make them do anything conceivably possible, no waiting at all.
  9. File compares show that the github rom file is the first version that Eyvind offered. BUT functionally identical applies to all of them.
  10. From this post https://atariage.com/forums/topic/122470-ram-upgrade-applications/page/2/?tab=comments#comment-1481893 I believe it to be the only form of it ever published in the wild as I've not seen either a whizz or ICD version anywhere, but the above is it just the same.
  11. Your memory has been upgraded and you don't need a sysinfo program to check it, the built in self-test will show four larger bars at the bottom of the standard memory test screen when it's done with the standard ram test with the smaller green or red squares. Those larger blocks underneath the standard display indicate one 16K bank window each, but the original code for that test is defective and it only shows two repeated blocks as the four and only the two banks are thus "tested". This extended memory test (defective as it is) was the last OS version used for 130XE so was included in the XEGS as is, even though the stock XEGS doesn't have extended memory usually - the code for it is still there and if extended memory is not detected, then the memory test code just cycles back to the beginning to start all over again. Just like it also does when extended memory is detected and the code does the four bars at the bottom, it also ends with a jump back to the start to repeat the testing.
  12. Just jumper them until you get some 33 ohm replacements. You might even get lazy and leave them in the package while using the machine. They were never necessary in the first place is the point. More on point some things are done for engineering "etiquette" and 33 ohm ram resistors are just that. Keep that pinky in the air kind of deal.
  13. The way it was originally is left bank (unchanged) is the main system ram and the right bank only has to do with the extended memory talents. You've changed the wrong ram if you want to boot it. Might as well change it all out now? One bad chip effects that one bit of all 64K of memory BTW so you found one bad chip in the extended memory side and changed all of them out while resistors were swapped, and now it doesn't boot indicating a bad solder bridge/connection somewhere in the swapped ram section. It could always have been Freddie, they go south on occasion too. The resistors only swap memory in 64K chunks and only the system ram boots the machine, extended memory does nothing until you call upon it with ramdisk software for example. So extended memory resistor could be left one legged and the machine would boot up fine, but it will fail to function any use of the extended memory unless that resistor is attached. Not sure which resistor supplies /CAS signal to which column of ram, but if you've got a datasheet for your memory chip you can find that pin number and test it with a VOM meter to the resistor pad responsible for that column of ram chips.
  14. You can pause the display with CTRL + 1 keypress combination, but 64 files won't fit on a 40 line display, no how, no way. So you'll have to take notes of files with names that look interesting as you pause and restart the display with the CTRL + 1 toggle. And then do whatever after the display is done scrolling. Otherwise post #2, instruction 1? There should be BASIC programs that will print out the directory, but I've not even looked for one in 20 years if you were after a hard copy.
  15. Pin one does NOT connect anywhere so good to go. Can you wash the board with 90+% isopropyl alcohol in order to clean up rosin, flux residue? Sometimes they produce a battery of sorts with the mixture of metals involved and that can cause a good soldering job to perform in the strangest manner, especially completely brain dead. Use a toothbrush to scrub around some while sloppy wet with the alcohol. I always tried to use my sisters toothbrush if at all possible, but you can buy one too. Pin one would have a purpose if the chips for a 256K expanded memory were installed. 64K just doesn't need pin 1.
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