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These
jumpers are
JP6 JP7
JP10 JP11
JP12 JP13
NOTE:JP8 and JP9 are the same for all
systems, and should not be altered.
They work in pairs, so only one of the pair is connected
at a time.
The even numbered jumpers (6,10,12) are connected to
+5.2V (logic 1) and the odd numbered jumpers are
connected to ground (logic 0).
So to switch countries all you need to is break the
existing
connections on the board and install a switch.
This is simple enough for a 2 country soluttion (Jap/Eur
or Jap/USA)
but for a 3 country switch you either need
a)2 or more switches
b)a 3 position switch and a bit of electronics
We're going for option b.
Here's which jumpers are connected for each territory
European
American
Japanense
Going back to our logic 1 or logic 0 for each jumper
pair,
these settings translate to.
European
JP6/7 0
JP10/11 1
JP12/13 1
American
JP6/7 0
JP10/11 1
JP12/13 0
Japanese
JP6/7 1
JP10/11 0
JP12/13 0
So all we need do is connected a wire to the mid-point of
each jumper pair then set these lines to 1 or 0
appropriatly.
The most obvious solution is to use an OR gate (7432) 3
resistors and 3 position switch.
You then 'OR' the European and American positions and
connect the output to JP10/11.
The solution presented here uses a hex inverter instead
(7404) which means less components, less soldering ; and
the components are easier to find (for me, anyway).
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