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Bruce Tomlin

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About Bruce Tomlin

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    River Patroller

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    CD C9 01
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    San Antonio, TX

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  1. I think there was also an update to the hi-res graphics for more colors. This seems to be the same as the mod in a Byte article from June 1979, which used the 8th bit to shift the pixel color of the other seven bits, adding blue and orange.
  2. FWIW, in San Antonio we've been having the remnants of XCSSA (eXotic Computer Systems of SA) meeting at the 10bitworks hacker space on the second Saturday at 1-3PM. (with the first Saturday as a fall-back since there have only been two of us for a while now) It started out in its deep past history as an Amiga user group, now it's mostly what cool thing Charles and I can come up with to show each other and work on for a while. A few months ago Charles was refurbing a couple of old Amigas, then lately an old Windows 95 era computer with some special ISA card that he wanted to get working again. And I've brought my recently acquired Mac Pro 2009 a couple of times to show some of the upgrades I'd been doing on it.
  3. Also adjusting the infamous white gear can make it work. Basically it controls the focus distance and it's loose enough that it will come uncalibrated with use. But it's such a pain to get in there that I stopped bothering. At least you can use a lens cleaner disc without taking everything apart.
  4. And where does that output go? To the controller port, where not only can it be fed back through the controller, but through accidental shorts with input pins/wires. That's a male connector, all it takes is something metal brushing against two pins. It could also possibly happen with non-standard controllers. (what happens if you plug in a 2600 paddle controller?) But this is all speculation about a dubious design decision. It's not the outputs that are in danger, it's the inputs. (otherwise it wouldn't be the '541 that gets damaged) TTL has protection diodes on its inputs that are reverse-biased, and can be very easily blown with negative voltages. What is not speculation is that I have actually encountered (and replaced) '541s with blown inputs. It is a real problem with the Colecovision that these chips can get damaged, in spite of being TTL.
  5. Not sure what brand of equipment RS relabeled, but if you google for 64-053 you can find replacements for sale on Amazon. And apparently it works with Hakko tips. https://www.amazon.com/Baitaihem-Replacement-Solder-Soldering-Station/dp/B06XW5HDHY
  6. I would say yes. However it's also worth just doing the same with aluminum foil and double-sided tape. I found that you can get a roll of sticky foil tape from Wal Mart and use a hole punch to make a lot of circles. Put the circles on the rubber keypad dots. First a word of warning about opening 5200 controllers: ALWAYS REMOVE THE BEZEL OVER THE START BUTTON ROW FIRST (those 3 buttons at the top), failure to do this can mess up the flex circuit! They aren't just the worst controllers ever, they even have a self-destruct trap! Now an explanation of what happens. The flex circuits are tin plated (or some other crap metal) which oxidizes to the point where the resistance of them plus the black rubber dots is not enough to register as a button press. Putting foil over the rubber dot lowers the resistance enough to make the button work. It is entirely possible that almost every 5200 controller ever made could have gone bad within a few years of being new! The only exception I have ever seen is on a pair of controllers with a "REV 8" flex. I found them in a thrift store, and they worked properly as-is. What is so special about that flex? Have you ever opened up a TV remote control? If you haven't, find a junk one and open it. Now look at the circuit board. Either the pads on the board are gold plated, or more likely they are coated with some black stuff. That is some kind of high-carbon epoxy or something. The important part is that it is conductive, but it doesn't oxidize. Those two REV 8 flexes are the only ones I have seen which had that black stuff on it. And think about this: I have also seen REV 9 flexes which are tin plated. So someone at Atari finally got it right, and yet they made another revision which went back to the crappy old tin plating! The other thing to watch out for with 5200 controllers is that sometimes the CMOS chips on the motherboard that interface to the controllers get zapped, so one of your controller ports will have some inputs not working. That requires the chip to be replaced. But you have to figure out which one to replace, so you want to have 3 or 4 sockets ready to put the old chip back into if you don't have a schematic and it wasn't the bad one. And yes, they are in a matrix, so you can't just press an arbitrary combination of number keys simultaneously. Every system comes up with its own matrix layout, so there is no way to make one controller that can work with multiple systems unless you put in a microcontroller that detects the scanning and responds accordingly.
  7. In my experience they can and do get zapped. It's so much fun having to take apart a Colecovision, desolder the old chip, then replace it, oh and don't forget having to order replacement chips first. And a socket, because of course it could happen again. My guess is that the -5 bias that gets put on the controller mode select line (assuming the schematic I have is correct) can eventually zap the LS541 inputs, though it may take a short in the controller cable for it to happen. TTL very much does not like negative voltages on its inputs. This is sort of the hardware equivalent of the WTF in the ROM where they made a subroutine to do the EX HL,DE operation. WTF were they thinking?
  8. Going to try to make it, will also try to find something cool to show off.
  9. My point is that rating logos like the ones that MPAA and ESRB use are trademarked to prevent some random guy from falsely using them without permission. They can throw lawyers at you for doing that.
  10. A bit late here, haven't been checking AA often lately, but more than in the past. The main thing I got was 45 junk Sega Genesis sports games for their cartridge shells at the Game Over $1 surplus booth. I'm still staying with Sega Genesis as my homebrew system of choice once I finally get back into it (life is finally starting to get back to semi-normal for me). But it looks like the cartridge boards I made 10 years ago won't be so useful in this era of 3.3 volts, so I'll have to do it again for SMT parts. Anyhow, the square with Bitgod and other homebrewers, and Ianoid's booth were really about the only memorable things this year. Maybe next year I can finally do something cool.
  11. I have the only Vectrex "color test" ("colors reveal your personality") unit that I know of, unless someone found another in the past 20 years or so. Naturally I dumped it right away back in the day. Just tried a google search, vectrex color displays kept getting in the way.
  12. Sounds more like a bug in the game startup that is simply incompatible with the earlier model. You'd think they would have tested on both, but ehhhh.
  13. I was talking about SG-1000, which doesn't have much RAM either.
  14. >ESRB Did someone actually go through the trouble of getting an ESRB rating or did they just plaster it onto the artwork like it was a pretty picture?
  15. On a Model 1 you can just use a 5-pin DIN plug (the other two pins are for RGB, IIRC), I think you even get stereo audio. On a Model 2, the connector is fiddly enough that you want to buy one already made. Anything better than RGB/stereo needs mods or circuitry to derive the picture from RGB.
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