Overhauling the Sega Astro City – Part 11, rewiring the cabinet

Posted Wednesday, 25th May 2011 under Arcade cabinets
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This one is best told in pictures. Let’s start with the before:

Looking inside the cabinet from the outside:

Closer up:

Power supply in focus this time:

Molex connections galore:

And the AC wiring, complete with heatshrink tubing and solder for the spliced connections:

Here’s the aftermath, with all the control panel wiring intact (since it will be reused), and all the excess wiring removed:

And for the sake of completeness, here’s the control panel without the bracket that houses all the molex connectors:

Now that all the wiring is out, next came the step of stripping everything out of the cab – the outer layers were removed that hold the bezel and speakers, exposing the fluro tube, and the monitor in its entirety (cage included) was also removed. To open up the insides for working, I also removed the partition that holds the PCB holder and separates the two halves of the cab. It really is looking like a shell now.

So, let’s start the refit – here’s a shot of the inside of the cab with only the new AC wiring present, with everything terminating to a female socket for ease of use:

Next up, add the step-down transformer to the partition to the right:

Add the partition to the cab and mount the SUN PSU into place; it’s positioned to allow for thick PCB boards, the MAME PCB or CPS2 setups, but still retain access to the unit for adjusting DC voltages:

… and another shot:

This next show shows the control box and the power board attached to the side of the cabinet:

The following closeups demonstrate when the control box and power board sit:

… and another:

… and another one:

Almost there – the JAMMA harness has been added, molex connections are complete and cable-tied close to the frame, JAMMA harness is hooked up and some RCA connections have been added for the output on the control box:

And there we go – all finished and much neater than before!

That takes care of the cabinet, but what about the control panel? We can’t forget that! Here’s a shot with the amp installed with all the wiring to the speakers and control box completed and the bracket re-installed:

And here’s the final shot with extra earth wiring grounding the monitor frame, amp, bracket and the coin slot chute/coin box:

Bit of a marathon run, but it came out really well. Next up – the new monitor!

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.

Overhauling the Sega Astro City – Part 1, power supplies

Posted Monday, 26th July 2010 under Arcade cabinets
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I’ve been meaning to write something up on this long-winded project for a while now, so here I go – not sure how many parts there’ll be to this job, so we’ll just have to wait and see 🙂

I’ve recently been looking at the existing setup inside my Astro, and can’t help but feel that it needs some work. The wiring is a bit of a rat’s next at times, I don’t know where all the cabling’s going, I’ve had to beef up to wiring on the 5v connections to increase the PSU’s output, the PSU itself is on the way out, as is the existing arcade monitor.

Where things got to a bit of a head was with regards to power issues – I’ve recently grabbed a Naomi and currently have a couple of Model 2 and Model 3 boards that need a reasonable amount of juice on tap. So, I figured that maybe I should investigate rewiring the way the power supply worked. The problem here was finding a power supply that couple happily take everything from a mid-80s PCB all the way through to resource-hungry Model 3 and Naomi setups. This left me with two options:

Option 1 – Parallel PSUs

In this case, I’m taking the 240v AC supply, chaining it across my existing 15A arcade PSU, chaining it to another 15A PSU and finally chaining it to a 3.3v PSU I bought a while back. From here, I then wire it to a distribution block, which connect to suit Naomi, Model 2/3 or JAMMA.

The pros with this is that all I need is another PSU (cheap and accessible), it runs off 240v (no need to run it through the transformer), and doesn’t require too much tomfoolery.

However, against this is – will it actually work on games that need a full load? What if one fails? Is it really safe to be mixing too PSUs together to get this kind of power distribution.

This then leads to option 2:

Option 2 – Dedicated PSU

In this case, the aim is to grab a Sega Sun power supply, since they are great pieces of kit and are certified to power anything you can throw at them.

There are some challenges with this – cost (they’re more expensive and more difficult to get locally), only 110v (therefore would require some extra work on hooking it into the transformer), no -5v output.

In the end though, I decided to go for the above setup – fork out the extra for the PSU, grab a Negatron to introduce a true -5v connection where necessary for older boards, and run them all off a distribution block.

However, after chatting with some more experienced arcade builders, I decided to change the model a little – instead of having a big distribution block, I decided to simply create a handful of male JST plugs for each connection (e.g. JAMMA, Model 2/3 and use standard cabling for the Naomi) and hook them directly into the JST power plugs on the PSU. The following is the final run:

So, I figured if I was going to start rewiring some areas of the cabinet to accomodate the PSU and make the whole setup more universal, there are two other factors to consider – amplification for line-level sources and getting the 12v fan from the Model 3 setup up and running when needed – you’ll see these (as well as switches to accomodate them and the Negatron when needed) have been added to the above diagram.

But I’ll stop here before I get too carried away – part 2 will deal with more of the planning behind this project.

To keep track of the whole project, just use the Sega Astro City Overhaul tag – the whole series will be added to it over time.