Mr Robot Posted January 19, 2019 Share Posted January 19, 2019 When the Multijoy game Sails of Doom was released late last year I decided I should make a Multijoy8 and use it as a learning opportunity for KiCad and PCB layout. It was harder than I thought! Here is version 1 It looks good but it doesn't work. I had got the wrong footprint for one of the Joystick Port connectors and the pin assignments were wrong. I manually fixed that and it now worked on my 800XL but didn't work on my 1088XEL, that turned out to be a similar problem to the SDrive MAX diode problem; I switched out one of the 1N4148 diodes for a 1N5819 Schottky diode and it worked properly now. Here is the hacked up board. Great! so I went off and ordered a batch of corrected boards and made one to test, here it is. It worked great so I made a few for people on Twitter That's when I noticed the error on the Silkscreen . The joystick ports that connect to the Atari are labelled 1 & 2, they should be labelled 2 & 1. This is the fix I came up with. So there we are, I now have a couple of Multijoy 8's for multiplayer gaming and a few leftover boards as spares. I'm happy to let other people have these if they would like one. It's a simple board with easy soldering and forgiving components but there is a fair amount of soldering required so it's great as a learning option if you are new to soldering and would like to get some practice before you attack a piece of history! I have some spare components left over as well, so I'm happy to supply kits or if you are not into DIY I can make one for you. In the unlikely event that I get more interest than I have parts, I'm willing to produce another run. PM me if you are interested. The parts required are (Including Digikey part numbers):- 4x 10K ¼w Resistor (CF14JT10K0CT-ND) 1x 0.1uf Ceramic Capacitor (1109PHCT-ND) 40x 1N5819 Schottky Diode (497-7053-1-ND) 1x SN74LS138N IC (296-1639-5-ND) 8x Male 9way DSub (AE10972-ND) 2x Female 9way DSub (AE11063-ND) If you don't have a 1088XEL you can use 1N4148 diodes which are much cheaper 14 Quote Link to comment Share on other sites More sharing options...
ivop Posted January 19, 2019 Share Posted January 19, 2019 (edited) As somebody who also did a MultiJoy8 board a few years ago, I love this form factor Re: 1N4148, do you mean using these won't work with a 1088XEL (and perhaps XLD?)? Why? Should this be considered a bug in the XEL design? Or am I understanding things wrong, which is entirely possibly of course Edited January 19, 2019 by ivop 2 Quote Link to comment Share on other sites More sharing options...
Mr Robot Posted January 19, 2019 Author Share Posted January 19, 2019 (edited) Thanks! Seeing your board and they no longer being available was the final push for me to make mine That's right, when I used 1N4148's the Multijoy worked with my 800XL but didn't work with the 1088XEL, directionals were OK, the fire button didn't register. Remembering the discussion about the SDriveMAX (which used to be built with a 1N4148 on one of the SIO lines) not working with the 1088XEL because the voltage drop was too great. The solution was to swap out the diode for a Schottky diode as the voltage drop was much less. I tried that on one of the Multijoy fire button lines and it worked. When the 2nd batch of boards arrived and I made one using just Schottky diodes it all worked great on both machines. I don't know if I'd call it a bug in the XEL, it's probably just way more precise than the original Ataris were. If the joystick 5v on an 800xl is actually 5.2v there is more room for the voltage to drop across a diode and still hit the 4.75v needed by the multiplexer than the exactly 5v on the XEL Edited January 19, 2019 by Mr Robot 4 Quote Link to comment Share on other sites More sharing options...
+Stephen Posted January 19, 2019 Share Posted January 19, 2019 PM sent. Love that board design. 1 Quote Link to comment Share on other sites More sharing options...
+mytek Posted January 21, 2019 Share Posted January 21, 2019 It's probably a bug with the XEL actually it really is a bug, but is not easily fixable (there is a way... see note below). Nice of you to say it's more precise, but that isn't the case. Luckily a diode change fixes that for you . BTW, I love your board design... very creative. --------- So what's causing the problem? To reduce individual components on the XEL design (as well as the upcoming XLD), a resistor network was used for the paddle and trigger inputs. Problem is due to the paddle requirements the resistance had to be 1.8K, which was too high for the triggers to register. So to make things better, and because I had a couple of extra resistors in the network, I doubled them up for the trigger lines. Turns out this worked perfectly fine for mechanical switches being used for the trigger, but apparently with a typical diode voltage drop it was once again a no-go. Changing to a schottky diode puts things back in range. However a better fix might be to piggyback individual 220 ohm resistors across the network for the trigger circuit. 4 Quote Link to comment Share on other sites More sharing options...
Mr Robot Posted January 21, 2019 Author Share Posted January 21, 2019 Nice of you to say it's more precise, but that isn't the case. I don't pretend to be an electronics engineer, I'm more an artist learning a new drawing program, before being able to draw. I'll probably cause Skynet when I design my first Schematic! BTW, I love your board design... very creative. Thank you! From a man of your skill, I take that as high praise indeed Quote Link to comment Share on other sites More sharing options...
+orpheuswaking Posted January 22, 2019 Share Posted January 22, 2019 PM sent!!! 1 Quote Link to comment Share on other sites More sharing options...
+Stephen Posted January 28, 2019 Share Posted January 28, 2019 Ooh - got my two boards in. I might try to get them soldered tonight. 1 Quote Link to comment Share on other sites More sharing options...
Brentarian Posted January 28, 2019 Share Posted January 28, 2019 Ooh - got my two boards in. I might try to get them soldered tonight.Got mine in too. Nice design! 2 Quote Link to comment Share on other sites More sharing options...
Mr Robot Posted January 29, 2019 Author Share Posted January 29, 2019 Excellent! I sent out five packages on Saturday Quote Link to comment Share on other sites More sharing options...
+orpheuswaking Posted January 29, 2019 Share Posted January 29, 2019 Hope mine comes today Quote Link to comment Share on other sites More sharing options...
Mr Robot Posted January 30, 2019 Author Share Posted January 30, 2019 Yours was one of the five. Quote Link to comment Share on other sites More sharing options...
+Stephen Posted January 30, 2019 Share Posted January 30, 2019 First one is assembled. I still need to clean the flux off the boards before installing the IC. I am going to blame poor lighting for the front shot. It looks like some of the lower legs (resistors in particular) are piled up with solder. That is not the case. 2 Quote Link to comment Share on other sites More sharing options...
Mr Robot Posted January 30, 2019 Author Share Posted January 30, 2019 Looks great! If you socket the IC it will stand proud of the d-sub edges, I left the socket out so the IC is protected whichever way up the board is laid. I don't think that IC is ever likely to need replacing. Quote Link to comment Share on other sites More sharing options...
+Stephen Posted January 30, 2019 Share Posted January 30, 2019 Looks great! If you socket the IC it will stand proud of the d-sub edges, I left the socket out so the IC is protected whichever way up the board is laid. I don't think that IC is ever likely to need replacing. Yeah - I know. I have a bad habit. I cannot physically bring myself to solder an IC to a PCB. Confession since I cannot tell a lie. I made a huge mistake. I soldered a male jack to one of the inputs, and the female jack to output #4. Now I have a quandary. Do I try to fix it and risk damaging the board? Do I just cut out the two bad jacks and replace them? Or, do I show the world my stupidity and use 2 gender-benders to fix, but also highlight my ineptitude? Should I start a poll? 3 Quote Link to comment Share on other sites More sharing options...
_The Doctor__ Posted January 30, 2019 Share Posted January 30, 2019 Geordi says any engineering worth doing should be done right! 1 Quote Link to comment Share on other sites More sharing options...
Mr Robot Posted January 30, 2019 Author Share Posted January 30, 2019 I did the same thing when designing the board, thats why the first go had all the pins reversed. If you like I can send you another male and female dsub. 1 Quote Link to comment Share on other sites More sharing options...
+Stephen Posted January 30, 2019 Share Posted January 30, 2019 I did the same thing when designing the board, thats why the first go had all the pins reversed. If you like I can send you another male and female dsub. Thanks - that would be great. I can't see any possible way of removing them without cutting the pins. I don't have a hot air rework station and they were a really tight fit even before soldering. Quote Link to comment Share on other sites More sharing options...
Mr Robot Posted January 30, 2019 Author Share Posted January 30, 2019 OK go ahead and cut them ill put a couple of connectors in the mail. 1 Quote Link to comment Share on other sites More sharing options...
_The Doctor__ Posted January 30, 2019 Share Posted January 30, 2019 a careful run with a dremel cutting disk, a few touches with the iron and it will be fine... You are right, watch the built up heat.. if you are careful, no one will ever know. It will still be perfect. 1 Quote Link to comment Share on other sites More sharing options...
+orpheuswaking Posted January 30, 2019 Share Posted January 30, 2019 Yours was one of the five. GRRR it didn't come (and I'm not that far from Stephen) - stupid USPS Quote Link to comment Share on other sites More sharing options...
Mr Robot Posted January 30, 2019 Author Share Posted January 30, 2019 Tracking says delivered... I'll PM you the tracking info. Quote Link to comment Share on other sites More sharing options...
yannsolo77 Posted August 26, 2019 Share Posted August 26, 2019 Hi, Do you still have one Multijoy8 available ? Quote Link to comment Share on other sites More sharing options...
Mr Robot Posted August 26, 2019 Author Share Posted August 26, 2019 I do, PM me your details Quote Link to comment Share on other sites More sharing options...
rmzalbar Posted December 5, 2019 Share Posted December 5, 2019 I would like a Multijoy8, if you have any available. Sending you a PM. Quote Link to comment Share on other sites More sharing options...
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