Dragon PSU Connections


PSU AC Adaptor ratings

Original D32 PSU is marked:

  Input:  240V 50/60Hz 20VA

  Output: 8.5V ~ 1.5A
          28V  ~ 250mA

External Power Connector (9 pin D connector on back)


    -----------------------
    \  1   2   3   4   5  /      (Looking into the male socket
     \                   /        on the rear of the Dragon)
      \  6   7   8   9  /
       \_______________/


   1   8.5V AC
   2   8.5V AC
   3   28V AC
   4   0V (centre-tap)
   5   28V AC
   6   Connected to pin 1 inside PSU plug
   7   Connected to pin 2 inside PSU plug
   8,9 D64 circuit diagram shows both these connected to pin 4 but these
       are not connected inside the plug on two D32 PSUs I've checked.
       They are all commoned together on the power regulator PCB.

Power Regulator Board to Main Board Ribbon

                  Power Connector
 _______________++++_____________________
|                                        |
| Modulator                              |
|                            Heatsink    |
|      ^^^^                              |
|______|||||||||_________________________|   (Unconventionally, 9 is the
       987654321                              marked strand.  Numbering
 ______|||||||||_________________________     convention matches the
|      |||||||||                         |    circuit diagrams and PCBs)
|            vvv                         |
|                                        |
|                                        |

 Pin  Direction  Function

  9       ^      Composite Video to modulator
  8       ^      +5V supply to modulator (linked from pin 2 via main board)
  7       ^      Sound to modulator and monitor socket
  6       ^      Composite Video to monitor socket
  5              Ground
  4              Ground
  3       v      -5V (D32) or -12V (D64)
  2       v      +5V
  1       v      +12V

D64 power regulator PCBs have a -12V regulator (7912) fitted for the RS232 port instead of a -5V (7905) originally fitted to the D32s. A small -5V regulator is used on the D64 main board for the video circuit.


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Graham E. Kinns
Graham@grempc.demon.co.uk

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Last update: Wed, 14 May 1997 15:21:02 +0100 (BST)