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asommer

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About asommer

  • Rank
    Space Invader

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Profile Information

  • Custom Status
    Livin' the Dream!
  • Gender
    Male
  • Location
    Boone, NC
  • Interests
    Atari, Arsenal, web development, electronics repair, game development.
  • Currently Playing
    River Raid, Shovel Knight, Tie Fighter
  • Playing Next
    X-Wing, Indiana Jones Atlantis
  1. I'm not in Raleigh, but I'm in Boone
  2. Maybe a fiberglass pen would help? Could also try a dab of isopropyl alcohol. Err ya, what @flashjazzcat said
  3. I've replaced the 138 demux with a new 74LS138 and have the same issue with the ROM test. When the machine works (usually when it's cold and only for a few minutes) the CE pin on the ROM has 0.9 volts (low) and when the ROM test happens the voltage is 1.5v. The same can be seen on the OS pin of the MMU. Not sure what to try next? Thinking to get a new MMU from Best Electronics cause they're pretty inexpensive and either way it may be nice to have a spare. Also, the traces between the MMU and ROM look good and test fine for continuity.
  4. I switched out the memory and the same ROM test failure occurred, I've ordered some 74LS138 replacements, so I'll report back when they get here. Thanks again
  5. I have the 64k upgrade kit, would you recommend doing that?
  6. Christmas update, I finally received my 74HCT08 and replaced the 74LS08. Have the same issue unfortunately. The 2nd ROM test still fails. I've burned EPROMs, but I think I've made some type of mistake during the process because when I use one of the EPROMs I get a greenish/black screen and no boot at all. I'm pretty sure I've not burned the EPROMs correctly. I programmed the EPROMs by loading the .bin file I saved from the ROM and clicking Device > Program > then the Program button. Does that sound correct? Thanks all
  7. I like the hardware angle personally. I think Atari development comparing and contrasting modern microcontroller development would massively interesting. I may be biased as that is what I'm interested in though :-)
  8. shoestring, thanks for the reply. Since I'm new to EPROM burning and the software for the burner I wanted to make sure I'm not making some silly mistake first. Nezgar, also thanks for the reply. I tried with the "Check ID" unchecked, but it didn't work until I unchecked the "Pin Detect" checkbox... totally should have noticed that before. But like I said I'm new to this :-) So I was able to extract a 16k .bin file and ran the MD5 on it and it matches the 06daac977823773a3eea3422fd26a703 - SYSROM_BB01R2. From the comment: I take it that the ROM is for an 800XL and may not work with a 600XL? It could totally be that I ordered the wrong part :-) On the upside with the checksum matching that seems to indicate that it is a good chip... right?
  9. I've received the EPROM burner, but the chips are on back order or something. I'm trying to read the chip, but I'm not sure I'm doing it right. I've got a Minipro TL866 II+ and I set the "Select IC" to 27c128 @DIP28, then when I go to Device > Read it gives me a "Pin Detect error!". Not sure if I'm doing something wrong in the software, or if that means the chip is bad and unreadable? Thanks again for all your help and suggestions.
  10. tf_hh, thanks for the info about pin 14, I appreciate it. The pin did read a strong 5.09 volts so I guess it's good. _The_Doctor__, Nope, no broken swipes, bent pins or cold solder joints. Also, don't see any through hole leads touching. 1050, thanks for the suggestion have some 74HCT08s on order and will be here in a few days. Also, still waiting on some new EPROMs and burner.
  11. DrVenkman, I appreciate the reply and apologize for the confusion. The memory error was happening before I did the video mod. I used the TV out with both a 2600 cable and an RCA cable and the picture was super touchy. If I unplugged it and plugged it back in I had to wiggle the cable to get the picture back. So since I was going to do the video mod anyway (though I would liked to have the system working first to rule out any mistakes I potentially made) I went ahead and did the video mod. Since doing the video mod the video out to a modern flat screen TV has can worked absolutely fine. So the memory problem was definitely happening before the video mod. That being the case there could definitely be a problem with my execution of the mod. Here's some pics of the mod area and the ROM socket. If you can determine a problem with the install please let me know. I'd totally like to fix it :-) Also, great to know about the capacitors, after watching a bunch of YouTube videos on old 8-bit computers I didn't want to rule anything out. but I am far from an expert. shoestring, I checked the +5V on the ROM it was good and there is no short to ground. Thanks for that suggestion, I was curious about the voltages too.
  12. Thanks again shoestring, I appreciate your help. I switched the MMU with the one from a 800XL and the same memory test failure happened in the 600XL. The MMU from the 600XL did work in the 800XL too. I'll report back in a few days when the EPROMs arrive :-) Thanks again!
  13. So tried contact cleaner in the socket and it did boot to BASIC one time, but then after that the same memory test failure. I then replaced the socket and it got the same memory test error. It's almost like it it's completely cold it'll boot, but once it heats up (or if there's electricity recently through the board) it errors out. Could it be a capacitor problem? None of the caps are bulging or leaking that I can tell. Also, have some 27C128 EPROM and burner on order so maybe it's a ROM chip issue...
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