Apex MI-008 accessory board fit

Case with XF551 drive installed and 3.5" bay cover removed
Case with XF551 drive installed and 3.5″ bay cover removed

Okay…. time for the next step.  This time we are going to be doing some dummy fitting of the accessory boards we decided we were going to put in the MI-008 case.  These boards are still in the testing phase and are not fully a final version.  We’ll be connecting most if not all cables and essentially checking for cabling issues, room, and mounting hole locations.  Let the fit begin.

First off we will be installing the 1088XEL board and the XF551 foppy drive.   Connect the front panel power switch and led to the 1088XEL power on and led headers.  We’ll also install the XEL-CF3 board with a 10″ ribbon cable into the MPB socket.  This will form the base installation.

Inside view of 1088XEL mainboard installed and case controls connected
Inside view of 1088XEL mainboard installed and case controls connected

Next we’ll be installing the ATX Power Supply adapter board and decide where to affix it to the case.

View of zip tied power cable
To help with cable management we’ll zip tie the power cable to the top rail on the right side.

Image to show where to attach ATX adapter board

I’ve decided to affix the board to the right rear grill of the case.  You will need to use either electrical tape or plastic spacer between the bottom of the board and the grill of the case, to prevent short circuiting.  You’ll need two screws and nuts of the correct size for the board mounting and the grill holes.


Next……  We’ll be placing three/four boards in the space between the front of the mainboard and the back of the front case grill.  This area is the largest area we have to work with.  Any boards fitted here will need to be fixed to the case floor either with mounting screws or liberal amounts of hot glue.  One is somewhat temporary and messy, while the other requires accurate drilling thorough the bottom of the case to provide mounting holes for the boards.  It’s entirely up to you which you chose.

The first board to fit is the XF551 board.  This board will contain the needed XF551 drive circuitry as well as the track display and front panel control signals.  We’ll also attach the power connector and data cable to the XF551 drive and pcb.  From there connect the SIO cable to the XF551XEL board.  For now we will leave the track display and front panel control cables off.  The pcb itself will set on the bottom inside middle position just behind the front grill.

Image of XF551XEL pcb with data cable connected to drive mech

Image of proposed case position for the XF551XEL pcb


The next accessory board is the Cartridge Guide adapter.   This allows us to access the cartridge connector on the 1088XEL mainboard. I’ve decided to cut open the top left front corner of the cover for the cartridge access.

Image of cart guide adapter with ribbon cable

Image of cart guide adapter pcb inserted into mainboard

Image of cart guide elevated position
This is the desired location of the cart guide position in the case

The trick here is how do we attach the adapter high enough off the floor of the inside case and provide strength to push down on the adapter with out breaking the board.  Let me think on that for a little.


Now we install the SIO2IO cabling and board.  First off we install the DB25 Parallel/DB9 Serial connectors in the external slot.  There’s just enough room for the back of the connectors to clear the TO device.  Next we lay the SIO2IO board next to the XF551 board and connect  the cabling to get a better idea of how it will look.   Well obviously we are going to have to have some cable management plan.

As you can see from the picture above we have an interesting symmetry with the cart adapter and the SIO2IO boards.  One appears to directly above the other.  It would appear that by judicial placement of matching mounting holes in both the SIO2IO and cart adapter boards and the use of spacers, it may well be possible to stack the cart guide above the SIO2IO board.  It might still be nice to brace the cart board against the 3.5″ rail.  I’ll look into that.


We’re in the home stretch now.  Just a few more boards to dummy fit.

In order to connect the multitude of SIO controled internal boards we need an internal passive hub.  Here’s the easiest place to put it.  On the right side (the other side of the XF551 board).

Image of Multi-SIO pcb location


These two locations are going to be the toughest.  Mainly because we have a limit on the width and height of the pcb as well as depth for the controls/displays to extend beyond the edge of the pcb.  The plan is to put the SDrive/XEL CF3 combo pcb into the 3.5″ drive bay.   The CF3 card slot will be mounted on the pcb using stand offs and the swap button and led will be embedded into a 3d printed faceplate.

Image of 3d printable SDrive-CF3 faceplate
Rough visualization of the faceplate


Image of test SDrive/CF3 pcb
This particular pcb is not the final product, I just needed a ‘real’ pcb to visualize placement.

And finally the pcb that will allow display and controls of miscellaneous functions.  This is an early attempt at visualizing the controls and display fit.  The track display component is surface mounted and therefor much shorter in height than the other buttons on the pcb.  So I decided to stack it on top of the bottom.  That had the advantage of giving the needed height, while at the same time opening up additional pcb space for connectors and other parts.

Image of proto control board placement
Proto control board placement

I have since decided to modify the pcb a little and add an external headphone audio jack.  The current 3d printed faceplace looks like this.    Still this is not a final design.

Image of 3d printed control panel faceplate


One thing is quite clear from this exercise.  There is going to be a cable management issue and a resulting airflow problem.  So cabling is going to have to be zip tied to case bracing or together with other cabling.  The other thing is that it looks like we have been able to add all the extra stuff internal to the case that we originally planned and we still have some room left.  It’s not a lot, but with judicious work it might be enough to add other accessories.

The next step is to finalize the beta level accessory board designs and send them to the board house for manufacturing.  The next post will cover the makeup and features of each board.  Once the beta level proto boards arrive I’ll assemble them and begin final testing.