Overhauling the Sega Astro City – Part 10, mounting the MAME PC

I’ve talked before (here and here) on the MAME PC I’ve worked on as part of this project – today I have some images to show how I set it up.

The aim was to have the PC mounted in a way that would easily allow me to swap it in/out of the cabinet like a PCB. To do this, I therefore needed to have it mounted on something, and due to the size of the chamber in the Astro City, I also needed to take space into account. I actually got the idea from some ghetto DIY arcade sticks I’d seen on the net, and I have to say I’m pretty happy with the end result.

It’s made up from a slab of MDF that I cut to size just slight larger than the motherboard with the mounting legs, with some extra give on the side where the accessories (graphics card, etc) stick out to allow for space for VGA adapters. The motherboard is propped up on PCB legs and screwed into the MDF to hold it in place. The top layer where the PSU, HDD and JPAC sit actually has two 80mm holes cut in a figure-8 shape that allows the CPU cooler to vent into the PSU and then have the PSU exhaust the air. To insulate the JPAC, I grabbed an old plastic VHS tape case and cut it to shape the JPAC with a rotary tool and that’s placed between the JPAC and the MDF. Small squares were then cut to act as plastic washers for the bolts so that the JPAC’s PCB wasn’t damaged when bolted down.

The poles supporting the structure were actually one long screw rod I got from the hardware store with an M10 width. Appropriate nuts and washers bind it for each layer, and I simply cut it to the necessary sizes using my angle grinder.

Everything was sized up, and bolts secure all the pieces of the setup, including cards in the motherboard, the PSU, JPAC and HDD. All the cables are secured using cable ties. The power button is routed to a DP3T switch I had lying around – simply flick it up, and it mimics the use of a power button.

All up, it works well, even if it is probably a bit rough 🙂 I like it though!

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 7, working on the MAME PC

MAME PC on the workbench

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 😛

JPAC - properly setup!

… 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.