CoCo repack in PC

                 ATCoCo - Putting it all in one Box

                    By Mike Haaland - 72300,1433
                 Internet: 

      Written: December 14, 1988    Updated: January 15, 1989

   This article is  the procedure I have  used in order to get the
   clutter of  Computer components off  my desk and  into a single
   AT Clone case.  It has been put together and distributed to aid
   those CoCo  owners who are tired  of the mess,  to do the same.
   I cannot take  responsibility for any damage you may do to your
   system while attempting the same project  described in the text
   that follows.  The need for such a  transplant  depends totally
   on your own tastes.

   The nicest thing about the ATCoCo (CoCo in an IBM type AT case)
   is  you  have so much  room for  drives,  packs, etc. that your
   system will be nice and neat without  the need of having cables
   running all over the place.

   Into the ATCoCo you have room for:

        Three half-height disk drives
        A full or half-height Hard Drive
        The CoCo Motherboard  (main circuit board)
        An MPI (Multi-Pak Interface)  RS Cat.# (26-3124)
        Four Paks (fit in four slots of the MPI)

   This is what I have installed into my ATCoCo!  If I can figure
   out how  to get the modem in there, I'll put it in there too!!
   My system has been running  this way for  over two months with
   no problems at all.

   Before you can get started you will need:

   (This case must be 6 inches tall inside.  If you have an XT case
   you can still use the  USING THE CLONE POWER SUPPLY  section but
   the actual installation will differ, as there is  not sufficient
   room in the XT Case to put the MPI (Multi-Pak Interface) on it's
   edge as described)

   and female. ( Including  the  RGB connector if you  are using an
   RGB monitor ).  For  the  cleanest  installation  get the female
   chassis mount connectors.

   and serial ports.

   the CoCo  motherboard  to the  MPI. (Or you can make your own by
   using the 40 plug on the board and wiring a ribbon cable).

   I strongly suggest getting the IBM XT 101 keyboard adapter that
   Bob Puppo  builds.  Or get a Keyboard extender cable.  Both can
   be found from various distributors in RAINBOW magazine.
   (If you ever received  CoCo-Ads from PD  Software  there was an
   article in the Aug. '87 issue entitled "Detached Keyboard" that
   will describe how to make an external keyboard setup yourself.)

   Make up  the extender cables  for the ports  and check that they

   Make the extender cable for the RGB plug.

  ground point on the COCO 3.

  cathode (positive) end of D1 or D2.

  anode (negative) end of D3 or D4.

  used  to be.  This is the  pin on Q1 that connects directly to both
  R19 (51 Ohm, 1/4W) and R20 (0.1 Ohm, 1W).

  anode (negative) end of  D14  to provide +12VDC to the input of the
  RF's +8VDC regulator.  This was previously  accomplished  via an AC
  coupled capacitor (C62) and  half wave  rectifier  (D13, D14),  but
  there is no longer AC on the board.

  By removing  Q1,  but still  applying +/- 12VDC to  IC8  (SC77527),
  you fool IC8 into thinking it is  doing the +5VDC regulation, which
  does  no harm as the voltage control (to the base of Q1) output has
  been disconnected.  The  internal -5VDC regulation is still done by
  IC8, which is necessary for cassette and serial (bit banger) I/O.

  This is how I hooked a Multi-Pak  Interface, ( cat # 26-3124 ) the
  newer small  white model with the satellite board modification for
  the COCO 3, to the same 200W IBM Clone power supply.

  so I could get to IC9 with a pair of wire cutters).   Also remove
  the on/off switch.

  slot 1 in the MPI labeled 2.  This pad is jumpered to all PIN 2's
  of the MPI slots. (Only  needed if using an older disk controller
  that needs 12VDC)*

  D1 labeled "-12V TP3".   This  will  supply -12VDC to all PIN 1's
  of the MPI slots. (Only needed if  using an older disk controller
  that needs 12VDC)*

  slot 1 of the MPI labeled "+5V TP1".  This will supply +5V to all
  PIN 9's of the MPI.

 *
  This modification has worked for me for about 8 weeks so far with
  no problems at all.  NOTE: If you don't have any peripherals that
  need 12VDC to power them you may skip steps 3 and 4.  Some of the
  older disk controllers DO need the 12VDC from the MPI!!!

   Remove you CoCo motherboard and MPI from their cases.

   Lay your  CoCo motherboard in the AT case  with the  ROMPAK slot
   facing away from  the drives  and the plugs facing the  front of
   the AT case, as far back in the case as possible.

   Mark where the four mounting holes on the coco are on the case.

   Drill out the holes in the case.

   You can  either mount  the coco  with the plastic  legs supplied
   with the case  or  build your own mounts using a small  block of
   wood under  each hole.  Keep the  CoCo  off  the  bottom  of the
   case ( about 1/8 to 1/4 inch ).  This will  give you enough room
   to run the DIN  plug extension  cables under  the board and will
   also allow the AT fan cool the motherboard.

   Put the MPI in the left hand  front corner of  the case with the
   slots pointing in  and the card edge  that connects  to the coco
   towards the back.  ( Put electrical  tape  over  the  components
   that may be  easily  shorted to ground on the bottom edge of the
   MPI such as D1)

   If you  have a small  extender  ribbon connector  for the 40 pin
   ROMPAK slot on  the coco, you can see how easily you can connect
   the MPI to the CoCo.  If you  want to make up your own, you will
   have to:

     De-Solder the card edge  connector and remove it.  Be careful,
     you will need it later!!    Solder a ribbon cable to where the
     connector  was.  Solder the other end of the cable to the card
     edge  connector.  ( Or use a small pre-drilled printed circuit
     board  and mount the  card edge  connector  to it and then run
     the ribbon to that). Be sure pin 1 goes to pin 1 etc.

   The last thing you will need to do is use a piece of sheet metal
   to mount all those connector on.  I cut out part of the PC  card
   slots and made a plate to mount them.  Plug everything together,
   and double check all the wiring. Mount the drives in their slots
   and hook  them up to the  power supply.  Plug your various packs

   Now that you have your ATCoCo all in the box and connected, here
   are a couple of "extras" that make you system  more professional
   looking.

   There  are usually three lights, a momentary reset button, a two
   pole (on/off) 'Turbo' button,  and a two pole  key switch on the
   case. I have found some uses for some of them and here they are.

   If you have a hard drive you can easily use one of the lights to
   indicate drive  access by  simply finding where the drive access
   light pins are on your HD and connecting them up.  This is a big
   help if  you have used the  fourth slot (behind the front cover)
   to put your HD in.

   You can wire one of the lights to indicate power on by  hooking
   +5VDC from the power supply or and the other side to ground.

   The 'Reset' switch  can be wired up  to where the original CoCo
   reset  button is.  Remember, you can't  get to the original one
   now!  Simply remove the  old reset button from the CoCo and you
   can wire the new button to where  the reset button was.  If you
   can,  get the male pins that will plug in to the connector from
   any electronics supply store  and mount them to where the reset
   button was and plug the switch to that.  This will make it easy
   to remove later if you need to work on you CoCo.

   Now if you can, remove the plaque from you old CoCo 3 top cover,
   the one that says  'TANDY 128K COLOR COMPUTER 3' and mount that
   on the front of the new ATCoCo Case. (For the completed look!!)

   This text  file is how I did  it and I assume  no responsibility
   whatsoever  for anyone following  the procedure  described above.

CoCo repack in PC

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CoCo repack adapter

CoCo repack Keyboard

"CocoRepack" - How To Transfer A Coco Into an AT Style Case

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CoCo repack in PC

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CoCo repack adapter

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"CocoRepack" - How To Transfer A Coco Into an AT Style Case

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