Overhauling the Sega Astro City – Part 8, building a control box

Posted Monday, 25th April 2011 under Arcade cabinets
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Today I’m going to talk about the control box I built as part of the Astro City overhaul.

The purpose of this was to achieve the following:

• Switch between stereo and mono output, with the mono input spliced internally to be two-channel mono audio, all via RCA sockets
• House a -5v output produced by a Negatron with a master switch to enable/disable the function
• Distribute +12v to a fan with a master switch to turn on/off the fan
• Distribute +12v to power the audio amplifier
• Route a GND connection to the JAMMA harness, which ensures GND runs across all connected GND loops on the harness regardless of which power connector is hooked up to the power supply (e.g. ensures GND on the JAMMA harness even if I’m powering a NAOMI board direct from the PSU)

The other aim was for the connections to be modular and terminated with molex connections. This way I could build the control box on the bench before fitting it into the Astro City.

The first step once I gathered all the components was to mark out the holes to drill for the RCA sockets and switches:

Once that was done, I drilled out all the holes and fitted all the sockets and switches.

Next up, I went about wiring the audio components together using a 3PDT (3 pole, double throw) switch to go between the two sources, and brought in a master voltage cable to bring GND, +5v and +12v from one of the extra connections on the Sun PSU that weren’t used for supplying the main voltage to the PCB or harness. From there, using hot glue and some cut-down wall plugs, I created some points to screw in some project board that acted as a voltage distributor and hooked up +12v to the two switches (one for the fan, one for the Negatron), and a second piece of project board to house the Negatron. I also wired in an extra GND point to be distributed to the JAMMA harness with the +5v from the Negatron, and added those along with a GND and the +12v for the fan to a standard 4-pin molex connection as used on disk drives in a PC.

In addition, I also wired a +12v and GND to a plug to fit the power socket for the audio amplifier.

The end result came out like this:

Inside view of the box:

Inside view of the top half:

Inside view of the base:

With this completed, I can start gutting the existing cab and modifying the JAMMA harness to suit the new setup and the various molex connections as part of the project.

As noted before, posts on the refurb are being done ad-hoc, so to keep track of the whole project, just use the Sega Astro City Overhaul tag, as the whole series will be added to it over time.

Getting Virtua Fighter 3 running in my Astro City

Posted Wednesday, 30th March 2011 under Arcade cabinets
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This one’s very retrospective, as I did this back in… late 2009 I think, or early 2010. It’s a response to the issues I’ve blogged previously with getting VF2 and VF3 to run on my cabinet.

I grabbed an AT PSU with some hacked wiring to a DIY power distribution panel. It was crude, but very effective – with some jiggling around and by using the power supply/connections in conjunction with a Model 3 – JAMMA harness I had from a previous order, I was able to get VF3 running on my cab 😀 Made me a very happy little nerd, I can assure you!

Angled shot of everything:

Power supply:

Squeezing everything inside the cabinet:

Success!!

The whole lot (and then some) are in the Arcade stuff – cabinets gallery.

Overhauling the Sega Astro City – Part 7, working on the MAME PC

Posted Monday, 21st March 2011 under Arcade cabinets
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As part of the Astro City overhaul, I wanted to recycle my old P4 hardware and use it on the Astro City. To get there, I’ve installed WinXP since I still had the license valid for this PC, along with MAME 0.128 that I had handy, and will use GameEx as the frontend. The following are the hardware specs:

CPU: Pentium 4 Socket 478 3.2ghz CPU with Hyperthreading
Motherboard: Gigabyte GA-8S648FX
GPU: Gigabyte ATi Radeon 9600XT w/256mb RAM
RAM: 1gb DDR-400
HDD: 40gb Seagate IDE HDD
Network: 10/100mbps LAN NIC

As you can see, it’s nothing terribly powerful by today’s standards, but it’ll have enough juice to run classic sprite-based games, which is what I wanted. The beauty is that with the LAN card, I can remote into the machine once the initial install’s done for maintenance and setting up programs.

To interface the PC with the cab, I’m going with a J-PAC interface, which takes the VGA and PS/2 sockets from the PC and puts them into JAMMA standard so you can simply connect the PC to the cab via the JAMMA harness. You need to push the video card into outputting a 15k signal though, which can be done on most ATi cards by using Soft15k, and it worked fine for my setup.

Special note to all J-PAC users though, be sure to set the jumpers on the J-PAC PCB to 15k – I was getting a rolling picture when I first booted and thought something was wrong with the video card or the chassis. I powered off the PC and set the jumpers as per the below, which also happens to be the configuration Ultimarc (the manufacturer) suggest you use 😛

… and it worked fine after that 🙂 The only other issue is audio, but since I’ll have an amp in the cab as part of the overhaul, I’ll just have a 3.5mm headphone socket to stereo RCA cable ready to plug in and run it that way. Sorted!

As noted before, posts on the refurb are being done ad-hoc, so to keep track of the whole project, just use the Sega Astro City Overhaul tag, as the whole series will be added to it over time.

Overhauling the Sega Astro City – Part 6, audio update

Posted Tuesday, 2nd November 2010 under Arcade cabinets
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Well, the stereo attenuator I had planned for the Astro is no more – I can get mono attenuators, but not stereo with the level of performance I’m after. The solution? One of these:

It’s a cheap mini stereo amp. In fact, it’s so compact, it’ll fit nicely inside the flip-up control panel on the Astro, so it’ll be easy to operate.

I wasn’t sold on these mini amps, but after reading some recommendations from other people who have used this same model on Aussie Arcade, I thought I’d give it a whirl. Considering the cost ($15!), I’m pretty happy with the outcome. Should work well to amplify both the mono amped output from the JAMMA harness, or the stereo line-out that needs amplifying.

As noted before, posts on the refurb are being done ad-hoc, so to keep track of the whole project, just use the Sega Astro City Overhaul tag, as the whole series will be added to it over time.

Overhauling the Sega Astro City – Part 5, roundup

Posted Wednesday, 6th October 2010 under Arcade cabinets
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Continuing on from part 4 of this series, let’s move on to part 5 – a short summary!

With all the groundwork done, I’ve whipped up a short summary noting my “to-get” list:

Item	Comments	Price
Terminal block	2x 12-way 30A blocks, dividable	$5.70
3m AC cabling	For new AC wiring	$7.50
General purpose hook up wiring	Better quality wiring for general purpose stuff	$4.95
New JAMMA adapter	Replace existing, tired JAMMA cabling	$19.95
Naomi Molex adapters for: (a) male Model 2/3 adapter, (b) male JAMMA, (c) male and female for 12v/GND lines for accessories	Naomi molex plugs included with PSU; if can’t get female Naomi molex plugs, run an extra 12v and GND run from each adaptor to a more generic molex, and use that to hook up to a molex off the 12v patch bay	$15.00
Molex adapters for chassis and fluro	To be determined	$15.00
2 x red SPST 12v switch	Used to power fan/negatron	$7.90
1 x green SPST 12v switch	Used to power audio	$3.95
1 x 3PDT switch	Audio source switch	$7.95
2 x 120mm fan guards	For protecting against injury on 12v fan	$9.90
Negatron	Used to obtain -5v on the JAMMA harness	$25.00
Stereo audio volume controller	Fit to outside to replace current controller, runs off final volume output	$21.95

That’s my theoretical list with pricing, which may or may not change over time – these posts are a little retrospective, so more updates will come as they happen. Note that this list doesn’t cover the big purchases, which are the Sun PSU and the chassis from Jomac, this is more the ancillary goods to help get everything together.

Once everything’s been gathered and finalised, I’ll then prepare a project timeline noting what needs to be done in the correct order to remove the old components, fit the new ones, test, and finalise the project. We can only hope there isn’t too much scope creep 🙂

So that’s part 5 – part 6 and onwards will be ad-hoc updates, so to keep track of the whole project, just use the Sega Astro City Overhaul tag, as the whole series will be added to it over time.