Cromemco JS-1 Joystick Replica

[nullvalue]

So to go along with the Dazzler replica we've been working on, I'd like to get a couple of joystick "consoles" to go with it. I plan to have a Dazzler exhibit at VCF Midwest and think it would be great to have a working demo where visitors can play some actual games. Problem is, these joysticks seem to be pretty rare. In the past 2 years, 3 have sold on eBay.. two were in rough condition and sold for ~$100, and 1 in good condition sold for over $500. On top of this, I'd like 2 joysticks for some head-to-head play. So, barring someone reading this and willing to sell me a couple.. I've been making plans to build my own. I'd like to try to make it as close the originals as possible.


Set of JS-1 consoles at the Smithsonian

With this in mind, I've been making a few purchases.

The hardest part is trying to find an enclosure that'll match the originals. I spent several hours looking at different designs in both plastic and aluminum, but nothing was really close - until I stumbled across this. The Hammond 1456FE1WHBU. It's soooo close, it's aluminum and even has the right color scheme. It maybe doesn't have the exact same ° slope, and it's not quite as tall, but I think it's the closest I'm gonna find. These enclosures run about $34. The thing I'm going to less comfortable with is opening up the holes necessary for the joystick & buttons. I may draw up the cutting pattern and bring it to a local machinist, unless someone reading this would have the tools & expertise to help me out?


The joystick itself is probably the hardest part to find. After reading this excellent writeup, it confirmed my hunch that these were originally used in model airplane transmitters. I found this "as-is" Kraft Sports Series transmitter on eBay for a pretty good price, so I snagged it. While I hate dismantling another piece of vintage equipment (especially also as an RC enthusiast), it'll be for a good cause. Plus this model transmitter has two joysticks, so I'll only needed this one controller.


The next hardest part to find, at least according to that writeup are the 45-ohm speakers. They may not be selling these new anywhere, but I was able to nab a nice lot of them on eBay for a decent price. My only concern with these is that Hammond enclosure is exacly 2.5" tall, same as the speakers so they may not fit pointing out the back like the original. Worst-case, I'll mount them downward-facing which shouldn't be too big of a problem considering the enclosure will be on rubber feet.


By some fortune, I already have the D+7A top edge connector + cable part, though the plastic is oddly discolored. Not concerned about that, but looks like I may need to redo the wiring to support 2 joysticks. I don't think this part would be too difficult for anyone to remake though, and I think Walt Perko designed a 3d-printed enclosure to match the original.


The rest of the components all look really common. I may not go with original/vintage Cherry switches, but they're still making plenty of high-quality mechanical keyswitches and I have a bunch in my stash.

So, what do y'all think? am I missing anything obvious?

 

[1944GPW]

Looks like the makings of a nice replica. If the speaker almost fits the back panel short of twice the metal gauge, you could use a fine cut flat file to put flats across the diameter of the speaker frame and then it ought to fit.
There are really plenty of old RC transmitters on eBay so you needn't worry about scarcity. Back in the 70s and 80s I used exclusively Futaba gear for my RC planes/tanks/boats/cars, Kraft was a brand we only saw in the big US magazines like Model Airplane News.

 

[Hugo Holden]

As soon as I saw those Joysticks I recognized them as from the Kraft controller ( I have one). Then scrolled down and saw that had already been figured out !

I would cut the holes out myself, it is important to protect the surfaces with tape. You need small files and a small diamond file set is helpful and once done smooth the cut edges with 600 then 1000 grade paper then clean with contact cleaner, after that mix up some matching paint and paint the cut hole edges and you can make it look like the holes were cut at the factory before it was painted, though if they were done at the local engraver/machine shop they would look very good too. You can also use the face of the Kraft controller as a template.

What were the Dazzler games that used the controllers ?

 

[nullvalue]

Great idea about using the controller as a template! It looks like Chase!, Dazzle Doodle, Dogfight, Gotcha!, Spacewar, Tank War, and Track all support Joystick control.

Gotcha! source code was provided in the Dazzler Games publication, this should make adding joystick support to my Snake game pretty easy.

 

[Hugo Holden]

Great idea about using the controller as a template! It looks like Chase!, Dazzle Doodle, Dogfight, Gotcha!, Spacewar, Tank War, and Track all support Joystick control.

Gotcha! source code was provided in the Dazzler Games publication, this should make adding joystick support to my Snake game pretty easy.

It is also easy, if you cannot get 45R speakers (32R was more common and would work) to change that a little and use 8R or 16R speakers. The existing audio output stage is very primitive.

A small matching transformer would be easy.

They have applied DC to the speaker which is not a wonderful idea.The DC resistances of small speakers tends to be similar to their stated impedance. The current there could be as high as 90mA but it is an uncontrolled situation and depends in the gain of the particular 2N3904 if all was ok it would be closer to 50mA (still not ideal) if the transistor's beta was close to 300.

A standard small transistor radio transformer, 3 to 8 Ohm speaker and a usual single transistor class-A stage with the transformer as the collector load would be fine and maybe allow a better range of speakers. I'll just look up some part numbers, for the speaker though a 45mm unit would fit;

2pcs 1.75"inch 45MM 3ohm 5W Full range speaker square Neodymium Loudspeaker | eBay

(Neodymium Full range speaker 3 ohm 5W. Diagonal: 50MM, M3. Speaker x 2pcs. Installation hole distance: 35 35MM. Local pick up is not available. We will try our best to resolve the issues. excluded.).

www.ebay.com

Will post the transformer part and altered schematic soon.By the look of it, their output stage and speaker arrangement would at be give an max output around 60 to 100mW.

A reasonable power to target so there would be plenty of volume if required would be around 100mW.

I have attached a circuit that can deliver around 150mW before any significant distortion. As new parts though, it is harder to find physically small output transformers. These sorts of ebay transformers for vintage transistor radios are very helpful, but the supply is inconsistent:

Thordarson TR111 Transistor Radio Audio Output Transformer 4-8-16ohms 300mw | eBay

Find many great new & used options and get the best deals for Thordarson TR111 Transistor Radio Audio Output Transformer 4-8-16ohms 300mw at the best online prices at eBay! Free shipping for many products!

www.ebay.com

Otherwise the Hammond transformer suggested on the schematic, but they seem ridiculously expensive though at least the speakers are cheap.

The 27k resistor might need adjusting to achieve the exact emitter voltage.

 

[nullvalue]

That's great, thanks but I already purchased that lot (of 12) 45 ohm speakers. If it turns out they're under-powered, then I'll definitely upgrade that part of the circuit. I'll have extras in case anyone needs a pair. Trying to stick as close to the original as possible, even though I know it has some downsides. If you could help me find a 2N3904 with the best characteristics, that would be greatly appreciated.

Also here's a pretty great find! Someone on eBay selling vintage Cherry keycaps individually, just the numbers 0-9. Perfect match! Seller accepted my offer of $3ea.

Vintage Cherry Keycaps #0-9 Individually Available (028-1275) | eBay

Caps are in excellent condition and price is for 1 piece <br>MFG part number of 028-1275- this is an old mfg number. <br>0-9 numbers available

www.ebay.com

 

[Hugo Holden]

Yes I agree to keep it all original as possible is always better.

Still, small High Z speakers are always somewhat of a headache to find replacements for that will fit and look similar to the originals. In my case I usually solve this by winding my own matching autotransformers, because an autotransformer is very compact and I have many small laminated iron cores & bobbins and the wire & I use my mini lathe with added turns counter to do the winding.

Another solution that would work is to eliminate the 45 Ohm speaker and the 2N3904, and simply use a small speaker (that fits) of anywhere between 3 and 16 Ohms and drive it with a common garden LM386 module like these:

2pcs Mini LM386 DC 3-10V Micro Audio Power Amplifier Amp Board Module 750mW New | eBay

2 x Mini LM386 Audio Power Amplifier Board DC 3~10V 5V Micro Amp Module 750mW. Output power: 750mW (max).

www.ebay.com

They have a volume preset so you can adjust it just right and the LM386 has plenty of steam to drive the speaker. Not original though, but, if you cannot acquire the exact original speaker part, then this section of the controller will be non original anyway so there is little lost.

For the 2N3904, with the original setup, just select one with an hfe of around 150. Some meters or transistor testers will read this value. Otherwise just check that the DC voltage applied to the 45 Ohm speaker terminals is in the vicinity of 1.8 to 2.5V but not higher.

 

[cjs]

The hardest part is trying to find an enclosure that'll match the originals....The thing I'm going to [be] less comfortable with is opening up the holes necessary for the joystick & buttons. I may draw up the cutting pattern and bring it to a local machinist, unless someone reading this would have the tools & expertise to help me out?

Another option you could consider, if you don't mind getting into a large pile of 3D CAD work (or can find someone else to do it for you), is to cons up the design in CAD and use a service such as Send Cut Send to make it for you. (I have no experience with them in particular, it was just the first name that came to mind because a YouTuber I respect uses them. There are no doubt many others, and I think even some of the PCB manufacturers are getting into this area too.)

Gotcha! source code was provided in the Dazzler Games publication, this should make adding joystick support to my Snake game pretty easy.

You have two joysticks, so if you're going to be taking this system to events you definitely make sure your Snake game can be played multiplayer. That way if you ever run into some dude at an event bragging about how his $50,000 computer can run multiplayer Snake, you can point out that your system is doing the same at less than one tenth the cost.

 

[nullvalue]

Another option you could consider, if you don't mind getting into a large pile of 3D CAD work (or can find someone else to do it for you), is to cons up the design in CAD and use a service such as Send Cut Send to make it for you. (I have no experience with them in particular, it was just the first name that came to mind because a YouTuber I respect uses them. There are no doubt many others, and I think even some of the PCB manufacturers are getting into this area too.)

Thanks, I'll consider it if these Hammond enclosures don't work out, but I think they are close enough for my use.. not trying to break the bank

You have two joysticks, so if you're going to be taking this system to events you definitely make sure your Snake game can be played multiplayer. That way if you ever run into some dude at an event bragging about how his $50,000 computer can run multiplayer Snake, you can point out that your system is doing the same at less than one tenth the cost.

Absolutely! Was already thinking about adding 2-player support. Head-to-head snake is far more fun! Brings me back to playing QBASIC NIBBLES against my brother.

 

[cjs]

Thanks, I'll consider it if these Hammond enclosures don't work out, but I think they are close enough for my use.. not trying to break the bank

I don't have much knowledge in this area, but I would definitely check prices before assuming that the custom fabrication is going to be more expensive than buying a pre-made box. After all, just like the PCB manufacturers, they're doing it all with CNC directly from the design files and fully automated equipment these days, and we've seen how much PCBs have come down in the last few decades.

(That said, I personally would just use the box; I do not have the patience to futz around with CAD.)

 

[nullvalue]

I don't have much knowledge in this area, but I would definitely check prices before assuming that the custom fabrication is going to be more expensive than buying a pre-made box. After all, just like the PCB manufacturers, they're doing it all with CNC directly from the design files and fully automated equipment these days, and we've seen how much PCBs have come down in the last few decades.

(That said, I personally would just use the box; I do not have the patience to futz around with CAD.)

Good call, I definitely shouldn't assume. But then we also have to consider paint & the nice texture the Hammond enclosure has that matches the original. Gonna be hard to replicate that. But I'll at least try to get a ballpark estimate. I didn't realize this type of small-batch fabrication was a thing.

 

[1944GPW]

You have two joysticks, so if you're going to be taking this system to events you definitely make sure your Snake game can be played multiplayer

You will need to disable the vertical detent for the other stick as it will be set up for throttle (likely Mode 1, RHS) but this is a simple procedure.

 

[nullvalue]

You will need to disable the vertical detent for the other stick as it will be set up for throttle (likely Mode 1, RHS) but this is a simple procedure.

Oh, wow - didn't even think of that. haha.. the other thing I was thinking about was that obviously these joysticks will not have an automatic return-to-center like most other computer/game console joysticks that people are used to, but I guess that's how the original JS-1 must have been, right?

 

[nullvalue]

After all, just like the PCB manufacturers, they're doing it all with CNC directly from the design files and fully automated equipment these days, and we've seen how much PCBs have come down in the last few decades.

Ok so one really nice thing on the Hammond site is that you can download a 3D model of the enclosure right from their site and upload it directly to SendCutSend LOL! So this should get me a rough estimate... Somehow though this only seems like half of the enclosure and we're already at the price ($35.60) of the full enclosure ($34.46), then you have to add paint, do the bending, etc.. Still! I'm impressed, this is a lot less than I was thinking it would cost, so I'll definitely keep this service in mind. Opens up a lot of possibilities!

 

[1944GPW]

The return to centre can be defeated easily by removing the springs, should be trivial to do

 

[nullvalue]

Well I guess my question was more along the lines of, did the original JS-1's have the springs installed?

I don't see them here: http://www.s100computers.com/My System Pages/Dazzler II Board/Origional Joystick Inside.jpg

 

[Torch]

I'm not willing to sell it, but I do have a brand new one you can borrow for measurements or whatever.

 

[hmb]

While the joystick mechanism used by the Cromemco controller is mechanically similar to that found in Kraft's RC transmitters, I wonder whether the resistance range of the potentiometers used for these two applications was identical. I have not been able to find any specs for the resistance range of those used for the Cromemco controller.

 

[nullvalue]

I'm not willing to sell it, but I do have a brand new one you can borrow for measurements or whatever.

Wow that is amazing, even better condition than the Smithsonian ones haha. How did you ever find a brand new one? That is a most generous offer, I'm almost afraid to accept it but I would treat it with the utmost care. Let me see if it would be necessary, or maybe I can just ask you when I have questions if you don't mind. Can you tell me about the joystick, does it automatically spring back to center or does it stay in the position you leave it?

hmb also does bring up a great question about the pots, I may ask you to just take some readings for me at some point.

 

[Torch]

It automatically centers. Feels similar to a Vectrex joystick.

I bought some WiRSa modems from you on eBay...I'm the guy just east of LOFS. If you're still in CP, I can drop it off sometime this week, or I can take whatever measurements or photos you may need and post them here.