MAME Table: Wiring preparations {Stage 7}

Post Overview:

This post details the preparations leading up to wiring the main internal MAME components.

Introduction:

This post details the preparation of the internal components in the lead up to wiring the JAMMA table. Wiring the components will be one of the largest tasks in this whole project.  The standard JAMMA wiring loom contains well over 60 wires that all need to be connected to components or securely insulated from shorting out.

Links to the full photo set for this build stage are also provided, but they contain no context information and thus are best reviewed after reading the blog entry.

The blog entry closes with post-build thoughts and where possible, suggested 'next time' improvement ideas.

Internal Component Preparations - Construction:

Overview/Background: The plan is to place, fit and secure 'everything' ready for wiring, but before making any holes, the components were simple placed inside the table and moved around until a satisfactory placement was found.



No holes, just finding space for everything.

There are a number of factors to consider during the placement phase.

The first factor is the folding control panels.  If they are to sit flush with the underside of the table, while in non-playing mode, internal components can't be located in the path of their closed position.

Also, and for reasons that go way beyond the scope of this blog, it's best that the power items be located as far away from the other (sensitive) components as possible. Long story short: think about a mobile phone near a radio, you get interference. Thus, the power items will ideally be located on one side of the table. 

JAMMA Board (in plastic, left), stereo AMP (center), a speaker (right)

Another issue is heat. The yellow/black tape shows where the (yet to arrive) 120mm fan will be located.  This will help remove the heat from the table generated by the PSU, monitor and stereo AMP.

As can be seen, the stereo AMP has been placed so that the heatsink is facing the fan's location and, is located on the opposite size to the 'hot side' of the table (where the PSU is located).  Its position near the JAMMA card will also cut down on cable runs within the table.



Stereo AMP

Holes for the volume, bass and treble controls are created.....


















.... the controls are push thru and bolted into place....

....finally the covers are fitted. (Pheeeew, manged to write that with using the word knob).

Recap Photo: control button holder

<Interlude>
While building the main table, it was envisioned that serveral control buttons would be needed, and the space for eight was allocated.  With hindsight and as noted above, if the control panels are to sit flush when 'closed', items can't be place in the folding location......so even for the two buttons that are required, they will need to be located elsewhere.
<Interlude over>

The control switches will sit in the white wooden block.

Having now received the JAMMA it is clear that only two control buttons will be required: A 'service switch' and a 'test switch'. 

In the real world these buttons aren't accessible from outside the cabinet (to stop the public messing with them), thus at some later point a locking, control switch might be fitted to disable them.

However, as I don't want to open the table to gain access (if setting changs are required) the control buttons will be located on player ones side of the table and just behind the PSU (Note: these are simple switches and aren't prone to interference).







Control button holes created.......

Control buttons.

...and buttons fitted.










The JAMMA Board: this is located on the shelf to allow clear access to both the input and output sides of the board - is has been secured via three small plastic feet.  In the photo, the facing short edge is the output side and on the left-hand side-edge is the JAMMA input strip. 

The input strip is where the JAMMA wiring loom will be conected. On the output side, we've got a (black) mono-out sound plug (at least that's what I think it is).  This will be run to the stereo AMP for better control and sound features. 

Next is the (blue/silver) VGA video out , this will run to the monitor and finally a standard (white) PC PSU power connector, which won't be used in this build (see 'stage review', below, for more details). 


Having (just now) checked the clearances, the monitor and JAMMA fit nicely together.

New hole created for the start button.

The control Panels are up next..... and yet more tweaks are required. We're missing holes for the start buttons.  These would normally be located on the main cabinet/table, but in keeping with the design specifications, these will instead be housed on the control panels.

I hate filing.......

Also the holes were very tight, and needed expanding..... much filing ensued. The orginal control panel build, stage 3, had been updated (again) to reflect these changes/oversights.

Buttons and Joysticks next: a few points of interest here. 

The underside of the buttons were aligned so that the wiring contacts are arranged around the outside edge of the buttons.  This is to create hand/wire space ready for the wiring phase.

Centered and clamped joystick

The joysticks were centered in the holes, clamped and then screwed into place. Having the joystick 'dead center' in the holes isn't a total necessity, providing they are able to move and make contact with all four switches. 

To check, move the joystick to all four points and listen for the click of the closing switch... no click means placement problems.

Completed controls: still a little ugly, but good enough. 

Final control panel point: the joystick 'rings' that sits around the joystick stems. 

A geeky argument that divides arcade builders is - should the rings be placed inside/under the control panel  or  on top of the control panel?

Geek camps are divided, but it appears to me (and as note, other opinions are availible) that these rings ought to be placed on top of the panel to stop general crap droping into the hole. 

Old-Skool purists may wish to place them inside/under the control panel tops, but in the end it's your choice  The frankly sad argument rages on, but if the 'on top' style is good enough for these grand-master MAME build kings, its good enough for this small project.

Speakers: two of them.  To get a wide sound space and justify the very reason for purchasing the stereo AMP, the two speakers need to be as far apart as possible.  Unfortunately this means that one of the speakers will need to be on the power side of the table, and thus will be prone to interference. To counter this, it has been put as far from the PSU as possible.








A 80mm hole for the first speaker on the hot side of the table is created.... the speaker is about 110mm. There are two reasons for the smaller hole.

Firstly, non-standard speaker grills/covers will be used and these are 80mm in size.  Secondly, the sound hitting the edge of the smaller hole will (hopefully) give a deeper bass sound..... hmmmmm, bass.

Not sure why the hole isn't completely round.......














Custom speaker grills, the sound will 'scream' out of the holes...













Speaker fitted (inside view) - had some bolts in the garage that were just the right size.

Secret button: top left

The finished underside: pre-fan installation. This post will get updated once the item arrives and is fitted.












 Finished inside, pre-wiring and pre-fan install.


{UPDATE: ADDED FAN}






{UPDATE: Addition of the fan}
Fan location maked......


















.....hole cut............
















and fan added.














Just a few words about the fun. I checked several custom PC building sites, did the reseach and this fan is THE fan for slient operations.









I could only find it for sale on Ebay, but trust me, track one down is well worth it....it doesn't make a sound.

I also connected the fan to a speed controller and place the dial on the underside of the table. Also, not only is the fan slient, it mounts on rubber legs to stop vibrations. The rubber corners were cut down to allow for mounting.

Stage Review/'Next Time' Thoughts:

Like stage 6 this build stage went well, with speaker installation going much better than expected.  The reason for the pre-build speaker worries was that due to the size of the custom grills (80mm), the screws (from the grills) stuck up into the main speaker area (110mm)....solution: file the grill screws flat on the inside of the table.

The small task of creating another hole in control panels, to fit the start buttons, was (yet another) oversight during the build phase - nothing major, it just needed doing.  What was a pain was filing out the holes to fit the normal buttons.

Recap Photo: JAMMA PC Inlet

The JAMMA board placement is also nice fit with the monitor. In the event of failure, the JAMMA would have been moved to the lower level, so again, not really a problem. On the subject of the JAMMA board - it has a standard PC PSU power connector it allow for incoming power.  Hence, I'm guessing, it's possible to power the JAMMA from a standard PC PSU. 

Even if I had known this pre-purchasing stage, I would have still gone with a dedicated PSU because of cost, size, noise, heat and the fact the cables would have needed butchering to power some of the items. 

Still with the JAMMA: it has it's own built-in front-end menu system for selecting games.  If this were a real MAME box, the HyperSpin front end software would have been used. Personally I've never used that software, but it would appear to be full of features and the choice of pro builders.

Finally, the purpose of the 'secret button' will be given in an upcoming post. ;)

Links to photo set:

Similar to build Stage 5 and Stage 6, the photo set for this stage contains more pictures than those in the above blog post.

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