# Yet another use for the Radica Space Invaders joystick :)

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### #76 remowilliamsOFFLINE

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Posted Tue Jul 18, 2006 8:50 PM

I've got a question about this circuit. Is it using TWO of each resistor? That is, is there a 2.2k between Up and Down, and a separate 2.2k between left and right? Or is there only a SINGLE 2.2k resistor shared between all four directional inputs? I'm using two different resistors, one for the horizontal circuit, one for the vertical circuit. So, each circuit is 6 resistors, for 12 resistors total.

Is that the problem?

A quick look at PMPs diagram on the first page tells me six resistors total, not twelve.

EDIT: I should say six resistor values total. If you're combining resistors to achieve different values, then it'd be more than six physical resistors.

Edited by remowilliams, Tue Jul 18, 2006 8:54 PM.

### #77 ParanoidOFFLINE

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Posted Tue Jul 18, 2006 11:48 PM

Thanks. Yeah, I'm combining resistors. 3 to make the 497k, 2 to make the 250k, and 1 for the 2.2k. Either way, you answered my question.

I tore it apart once again, and put it back together. This time, I pretty much followed PMP's first schematic, along with my schematic from this link: http://www.atariage....s...t&p=1101980

(simply to get a better visual idea of what was going where)

And it works much better this time. I still get an OCCASSIONAL ghost down when I'm pushing up. But instead of one ghost down for every first up, now I'm getting a ghost down about once ever 7 or 8 times. I actually got past the pit in BC's Quest for Tires... which was virtually unplayable before. I also went ahead and reoriented the stick correctly (up is now up, left is left, etc...) So I'm about ready to call it complete and just live with the occasional ghost down. In all honesty, BC's Quest, which is unplayable in emulation and with the 5200 stick, works pretty well, and it was the worst before, so I figure all the other titles will be much improved. I think I'm going to go treat myself to some uh, testing now, and enjoy the fruits of my labors.

Thanks again, PMP, and everyone else, for all your help on this. I can't wait for some of the other DIYers around here to make this stick so we can compare notes and see if this problem is just me. The only thing I can think of is that I'm about 600 ohms off the 497k Ohm value. But maybe it is simply a matter of analog being a kinda tricky and imprecise beast, so what works on one 5200 may not work so well on another.

And I'd like to add, this stick, even with the occasional ghost down, kicks butt! On games that would benefit from a digital stick, the improvement so far is drastic. I played Gateway to Apshi last night for about 45 minutes. I've gotten further in Montezuma's Revenge than I've been since I was probably 12. There is a lot of wiring involved, but the payoff is completely worth it.

Edited by Paranoid, Tue Jul 18, 2006 11:52 PM.

### #78 ParanoidOFFLINE

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Posted Wed Jul 19, 2006 1:32 AM

Curiouser and Curiouser...

So, on my 2nd Console, it works much better, on the first console, it works better, but not perfect. It was working OK on Montezuma's revenge, then, suddenly, it started NOT going down ladders again, unless I tapped it repeatedly. Although, occasionally, it WOULD start going down ladders again. Neat, huh? BC's Quest was also far worse on that console. Lots of ghost inputs, although better than before.

So, maybe I fixed a loose or shorting connection, but it seems that there are still some issues, and, I suspect that the settings on the Atari itself are also somewhat responsible for the issues.

The only unusual thing is that BOTH of these units show up as 4 port BIOS even though they are 2 port 5200s. Did the 2 port come stock with a 4 port BIOS at some point, or were both of these units modified by DIY or aftermarket upgrades later on? I got them from two different parties. Oddly enough, I also have trouble with a couple slots on my Atarimax cartridge not being able to load games correctly, on both boxes.

The bummer of it all is, the one that plays best with this joystick, has an annoying issue with the video kind of rolling or jumping. It doesn't actually roll, it just seems like it is picking up interference and the screen jumps around like it isn't holding sync. Any suggestions on this, anybody? The other one the video is flawless, but the controller doesn't work so well with it. I suppose I could just adjust the pot on that one and make it a RSI only console, if the regular analog sticks stopped working.

### #79 ParanoidOFFLINE

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Posted Tue Aug 1, 2006 1:28 AM

Has nobody else attempted this mod yet?

So far, I'm really loving mine.

### #80 nemsOFFLINE

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Posted Thu Aug 3, 2006 10:07 AM

I have one coming, so I should be working on it this weekend.

Since I already have a 2600 redemption adatper, I'm planning on modding the Radica stick into a standard 2600 stick (albeit with a second fire button). If I really fall in love with the stick, I might go back and do the full 5200 mod (but that amount of work kinda scares me).

Edited by nems, Thu Aug 3, 2006 10:10 AM.

### #81 ParanoidOFFLINE

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Posted Thu Aug 3, 2006 1:27 PM

The 7800 RSI mod is *far* easier... but, not quite as rewarding, either.

The 5200 RSI stick, you really feel like you've accomplished something. I think I made it a lot more work than it had to be, too. You could always wire the passthru to dangle out as a cable, and skip the Start, Pause, Reset, * and # buttons on the stick itself. That avoids having to cut into the shell of the RSI stick at all. It is NICE to have these buttons on the RSI stick itself, but you don't HAVE to do it that way... and THAT is really MOST of the extra work.

Now, with the Redemption and a RSI 7800 stick, you get a more flexible stick that will work for *both* machines... so if I had a Redemption, I'd probably go that route, too. I'm surprised nobody else has built one of these for the 5200 other than PMP and I, though. At \$5 plus parts, it is a GREAT deal for a digital 5200 stick.

### #82 remowilliamsOFFLINE

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Posted Thu Aug 3, 2006 1:58 PM

Now, with the Redemption and a RSI 7800 stick, you get a more flexible stick that will work for *both* machines... so if I had a Redemption, I'd probably go that route, too. I'm surprised nobody else has built one of these for the 5200 other than PMP and I, though. At \$5 plus parts, it is a GREAT deal for a digital 5200 stick.

I would have done of one these for sure, if I didn't have the Redemption 7800. <- That was one of the major factors that caused me to do the 7800 RSI mod in the first place

### #83 ParanoidOFFLINE

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Posted Thu Aug 3, 2006 2:20 PM

I noticed I've been giving PMP full credit for the 7800 RSI, but you're actually the guy who discovered the highly hackable nature of the RSI stick first, right?

Thanks.

I actually went hunting around for the RSI sticks today, and you can find them, but for \$20-ish... Which takes away a lot of the allure. I wish I had gotten in early and gotten a stack of these from GameStop.

### #84 remowilliamsOFFLINE

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Posted Thu Aug 3, 2006 2:43 PM

I noticed I've been giving PMP full credit for the 7800 RSI, but you're actually the guy who discovered the highly hackable nature of the RSI stick first, right?

I wouldn't say I'd claim to be the ultimate source, I know Keilbaca used an RSI for a 2600 mod (though I believe I went public first ), And PMP might have done his mod anyway. Great minds think alike ya know

What really grabbed me to mod the RSI was the inherent build quality of the stick, and the fact that the games weren't good It was just a matter of time before I converted it to a better use.

### #85 ParanoidOFFLINE

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Posted Thu Aug 3, 2006 9:40 PM

Great minds think alike ya know

And the rest of us follow.

I agree. I mean, it is obviously a PnP game that is designed to be disposable, but it has a great feel and the components, while not arcade quality, seem pretty well built. I can see it having a really good lifespan. If you wanted to put the time and effort and expense into doing a stick with Happs parts, it would probably last longer... but it would also cost a heckuva lot more than \$5 and require a lot more work.

### #86 nemsOFFLINE

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Posted Fri Aug 11, 2006 10:30 AM

I was able to find one on ebay and have it shipped to me for \$10 total. Last night I converted it to a 2600 stick w/2nd fire button. Hooked it up to my 5200 via redemption adapter and am totally impressed with this stick. Great feel.
Absolutely essential for playing any of the Pac Man games. I now want to find a second Radica stick as a back-up in case my first one should ever break.

Edited by nems, Fri Aug 11, 2006 10:31 AM.

### #87 nemsOFFLINE

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Posted Mon Aug 14, 2006 1:39 PM

To further customize, you can also wire up the no longer needed on/off switch. Some possible uses for the switch are to flip between:
• 2nd fire button for a 7800 vs. 2nd fire button for Sega Genisis (i.e. 2600 redemption adapter) [assuming you built a 2600 or 7800 stick]
• Buttons-A act as 1st fire and buttons-B act as 2nd fire vs. all buttons act as 1st fire
• Only buttons on the left are active vs only buttons on the right are active
Unfortunately you can only wire up one of these options to the switch. So pick which one best suits your needs.

Edited by nems, Mon Aug 14, 2006 1:53 PM.

### #88 ParanoidOFFLINE

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Posted Mon Aug 14, 2006 2:10 PM

I'm curious when these start trading or selling on eBay with collections in a few years, how much they will command. If just *one* person was making them in a limited run, obviously there would be more value to them... but as an AA DIY project... really, for the completist, their collection will not be complete until they've added one of each of these unique conversions to their collections.

Mine is available... I'll trade for a boxed, minty Quadrun!

### #89 remowilliamsOFFLINE

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Posted Mon Aug 14, 2006 4:15 PM

I'm curious when these start trading or selling on eBay with collections in a few years, how much they will command.

Just wait until I start selling my limited run individually numbered super edition autographed ones!

### #90 eegt97OFFLINE

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Posted Mon Aug 14, 2006 7:02 PM

Just wait until I start selling my limited run individually numbered super edition autographed ones!

And all for the very low price of \$92 a piece!

I finally started my 5200 conversion last night. I've put in mini-buttons for all the keypad keys above the stick and have put trimmers for the pots on a mini proto-board. Lots of wiring and soldering and drilling going on, but I think it will be nice to have everything on one controller. I hope it's done this week (and that there is enough room inside). Looking forward to getting this one done.

-Brian

### #91 ParanoidOFFLINE

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Posted Mon Aug 14, 2006 7:27 PM

Sounds a little more involved than PMPs circuit.

You've got trimmers on the pots, so it remains analog? Or is it digital, but you can tweak the resistance on the up/down left/right circuits?

### #92 eegt97OFFLINE

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Posted Mon Aug 14, 2006 8:00 PM

Sounds a little more involved than PMPs circuit.

You've got trimmers on the pots, so it remains analog? Or is it digital, but you can tweak the resistance on the up/down left/right circuits?

It's so I can tweak the resistance real time, not sure how necessary it is, but figured what the hell.

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