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Defence Force
@DefenceForceOrg
Game Developer (Adeline, Heliovision, Eden, Funcom), Retro Enthusiast (Oric, Atari, Audio), YouTuber (youtube.com/c/Dbugsstuff)
Norwaydefence-force.orgJoined September 2014

Defence Force’s Tweets

I'm wondering... should I keep the name on Twitter "Defence Force", or switch to "Dbug" or even to my actual real name? Originally I made the account to indicate the downtimes, maintenance and updates of defence-force.org, but we are far past that point now. 😅
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Since I was not able to find a pinout for the 36 edge connector, I used a combination of scope and contact check to find more of the pins. Some feels so random, like why are the difficulty switches for the left and right players and "speed" grounded, but "serve" uses two pins🤔
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I'm glad to see that all the work done to scan Oric books and magazines to make them available to everybody publicly is actually useful. I just wish they were showing at least some examples of what their reprints look like, and somewhat mentioned the source.
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I watched an upgrade video yesterday by where the audio circuitry of the Sinclair/Amstrad ZX Spectrum+3 is modified to fix sound issues. Generally improvements are modest, but here it's quite a change. Can hear at the bottom of that page:
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That explains the somewhat convoluted logic on the boards: To detect that the user pressed "1" by testing for a contact between the violet 🟣and green 🟢 lines, while green and gray would be "2" and green and orange would be "3". This reduces the number of required contacts.👍
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The RESET button works as expected: It does a contact between ground and some pin. 😅 All the other works in combination, which means they are not designed to handle multiple buttons being pressed at the same time: You either press 1 or 5, but not both at the same time. ⤵️
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I was wondering how the game select buttons were handled, it did not look like from the cartridge side there was a clear logic on why they would use a specific button for a specific game, but I guess that makes sense considering how they did it. ⤵️
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Today I traced another game, which was using only half as many connections on the bus, easier to check if I got anything wrong. Let say I want to try to build my own card, what would be the easiest way to have such a double sided cartridge connector attached to a breadboard?
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I opened the second light gun (the one which had a complete wire), and interestingly the trigger mechanism is different (uses a proper micro-switch), and the PCB is identical... except that one has actual components (a CD4011BCN / Quad 2-Input NAND) instead of holes 🤔
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This is possibly related to the presence of "Bat Position Adjustment" knows on the Super Sportif cartridge... but then, why don't the later games have any of these drift compensation knobs?🤔 Feel free to provide ideas, there are no stupid suggestions as far as I'm concerned 😇
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The analog joysticks on this console are using a pretty neat system, it's still working flawlessly after more than 40 years. What I'm wondering is why would you use a 100 k ohms resistance on the vertical axis and a 50 k ohms resistance on the horizontal axis. 🤔 ⤵️
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Always nice to get new colorful Oric games :)
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In honor of the #Oric's official 40th birthday we release our remake of the classic game #PUTUP (demo)! Download: forum.defence-force.org/viewtopic.php?
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Tracing even simple circuit boards is not particularly trivial when you take into account the messy solder blobs, non insulated bodge wires, glued over components, and tracks that pass under large components.🤔 I've too many "Ball Speed Inhibit" connections, so done for today 😅
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If there is any #oric owner with a working Microdisc, Jasmin or Cumana 3" drive around Manchester, maybe you can help?
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Does anyone have a 3" disk drive I could buy/borrow - preferably in UK/near Manchester? I seem to have lost mine and I have some archiving I need to do. Just to clarify I'm after a 3" drive as used by Amstrad CPC6128 / PCW and Spectrum +3, not the common 3.5" ones in PCs/Amiga/ST
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Basically it means you need to keep a list of redirects, that you never rename pictures or pages, that you keep the same technological stack so old links still resolve to something valid, even when they use parameters on the url, etc... this is not trivial at all. 🤔
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I guess anyone who has to use StackOverflow and find an answer of 5 or 10 years ago already know that most of the links in the answers are pointing to things that have vanished. I've tried to keep working links for Defence-Force.org these last 25 years, and it's hard! ⤵️
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Whoever claimed that the "internet is forever" didn't have to go back to the internet of 2009 for a research project only to find that 75% of the links go nowhere now.
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The final "cheat" is to use some label paper to reinforce a bit the box. It's not particularly pretty, but at least now the box can close, and actually keeps a proper shape, so the manual and the cartridge can be stored in it. ⤵️
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Second step, flatten the cardboard into submission by spraying some water on the back side and sandwiching it between two bits of cardboard, then use the power of books to let it rest during the night. Same method for the manual ⤵️
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A common issue with these old Pong games, is that everybody has the "Shooting Gallery" but without the gun. I found one which was used by kids, but they cut the wire, so I'll need to rewire it, but since it's super dirty, time to clean-up and look inside. ⤵️
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The main issue, is that most tape software did not really care about some important locations in memory, like the page 4 (which contains important DOS thing), or your own ripper program, so I had to relocate. But it's working, I've a DSK with the file now. 😅
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Fortunately, Symoon wrote some routines to call Sedoric from assembler (can find that in CEO-MAG issue 153), so I reworked the program to automatically load from tape and save to disk without human help. ⤵️
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My original ripper was kind of lame: Because I did not know how to call SEDORIC functions from a C or assembler program, instead I printed the command to the screen, so the user would run it from the interactive shell. That often worked, but in some case would get corrupted.⤵️
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No I just need to find my ripper/saver, which loads a program block by block without running it, and save that as Sedoric files on the Cumulus, then load that on the PC, but I guess that will be for tomorrow :)
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