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wileyc last won the day on February 17 2014

wileyc had the most liked content!

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About wileyc

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    Chopper Commander
  • Birthday 03/08/1970

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  1. I'll also keep an eye on the Yahoo Japan auctions. Controllers seem to come up pretty frequently for between ¥1000 and ¥1500; I'll grab 'em as they come around.
  2. Bad news, folks ... ... I hit both Super Potato and that smaller place out towards Ueno on Chuo-dori, and neither of them had any of the NTT controllers in stock (although they had some controllers with additional sliders that I had never seen before). They didn't know when they'd be back in stock. I'll keep checking every week or so, buy them when they appear, and let you all know when that happens. Sorry again ...
  3. I was going to hit Akihabara on Tuesday anyway. I intend to buy up as much as they have in stock and offer them to the community for cost plus shipping plus maybe five bucks for my efforts. I'll post back to the thread the results. I was thinking cost + shipping + maybe five bucks for my efforts per order for total. If anyone wants anything else from Super Potato (a partial online catalog is at www.superpotato.com ), let me know and I'll see if it's in stock. Worst case we can order online and have it shipped to my place from their warehouse in Osaka. This is all dependent on them actually having stock available -- I didn't see them on the website, so as I said I'll go in person and ask the staff.
  4. I live in Tokyo, not too far from Akihabara (and thus Super Potato). I don't have a problem with grabbing a few controllers and shipping them over to y'all.
  5. Well, I'm certainly on the fence now about buying a TI. Even though I love Bill Cosby, who was the best father figure a kid could want
  6. This is appropriate for a TI-99/4A forum? Shame on you.
  7. Out of curiosity, how much EE chops do you have? I don't know what level I should use when talking hardware here.
  8. *laugh* I learned a long time ago in Shenzhen: when schematics are published, the whole shebang is public domain. Keep your IP close and safe if you don't want it cloned. the original Ron Giles board and software was public domain the enhancements the Bud Mills service made where not.
  9. Well, you could try the Murata replacement for the 7805 and replace the diode to ground with a wire. That'd run the whole board at +4.3VDC, though, and I'm not sure the TTL parts on your board would like that. My testbed is 100% CMOS, so it interoperates with the rest of the system okay (the logic highs are within TTL tolerance, at least) but for the time being go with a high-current 7805 please. (the Murata datasheet has interesting disclaimers when used in a circuit like the HRD+: "The output is not intended to sink appreciable reverse current", for example
  10. ... which puts me on a design tangent track. The voltage output as measured from the output pin against board ground is actually +5.7VDC (on the HRD+ at least, IIRC the other variants too). This is done to compensate for the voltage drop across the battery backup protection diode, and is done by connecting the 7805 ground pin to ground through a same-spec diode. It's a neat trick to make a non-adjustable VR output a custom voltage, but drop-in switching replacements for the 7805 don't like it (definitely the CUI, maybe the Murata too). The Right Thing To Do is to replace the 7805 with, say, a switching LM317 workalike and set it for 5.7. That would require reworking the board, hence my silence when Opry99er mentioned the immediate heat concern. If folks want, I can speak to the germanium diode wired-OR mess in a future post. End design tangent
  11. Get CMOS Alliance 62256 from Mouser. The battery-backup circuit will be happier thereby.
  12. Hey, don't sweat it. I was a machinist's mate, for crying out loud -- needs of the Navy, etc, and I picked up EE because I thought that knowing the teardown procedure for a Rix lube oil pump was fantastically boring. Gotta start somewhere. Thanks for picking the HRD+ -- it's a good example of 99% good engineering with 1% compromise.
  13. *laugh* It's only 2130 here. Not time to sleep yet. A TL866 is a Chinese EPROM programmer that also can perform dead-chip tests on most 74xx logic (most notably omitting the 74xx245). If you're getting into the TI, I strongly recommend getting one. They're less than fifty bucks on eBay. Get one of those, plug it into a Windows machine, install the Chinglish software, and do a logic test on all of your chip pulls (including memory). Replace the bad stuff with either HCT or ACT chips (power saving, rail-to-rail, yadaa yadaa yadaa). Enjoy the goodness thereby.
  14. So, to use my one gig scheme, you'd pull all of the memory chips except for the ROS 6264, as well as the '154, and run what used to a) be the chip-enable for the '154s (plural) from the 259 stack to the daughterboard, and the synthesized address lines from the same stack to the same board. We're basically taking advantage of the board originally being designed to handle memory in 512k chunks; plug in 512k/8 SRAM and the 154 nonsense goes away. All that is for later, though. Let's get your board matching the HRD+ spec and working before we Frankenstein it. I'd really recommend picking up a cheapo TL866CS (and crossflashing it to the -A variant if you're up to it) to see what all you have to replace.
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