Circuit Notes
3 - 1
Revision 1 - 07 July
1999
Event 4
TECHNICAL MANUAL
3.1.8 Expansion Bus
The expansion bus is provided to allow for options to be added in the future. The
expansion bus is a buffered extension of the system CPU bus. It is not compatible
with Jandshog, Event, or ESP2 type expansion bus option panels, and they should not
ever be installed.
3.2 Front Panel Cards
All front panel cards follow a design similar to that of other Jands consoles. A
multiplexed 8 bit data/address bus is used to exchange bytes of information between
the CPU and the front panel cards. The pin connections however are not compatible
and under no circumstances should Event, ESP2, and Jandshog type front panel circuit
boards ever be connected to an Event 4 CPU card. Damage will result.
3.2.1 Card Select Jumpers
A jumper on each Preset and Assign card selects the address of the card in the system.
When installing new cards ensure that the replacement card has its jumper in the same
position as the card it is replacing.
The correct jumper position for a Preset or Assign card is equal to its position from the
left eg. the left most Preset and Assign cards have their jumpers set to 0, the next have
it set to 1, etc. Master and Palette cards have no address jumper.
3.2.2 LCDs
The character LCD modules use a single backlight driver circuit to deliver the high
voltage required for all of the electroluminescent (EL) backlights. This is the function
of the EL driver board, mounted near the power supply. This board receives its power
and an analogue control from the CPU card.
Note that intensity of the character LCD backlights reduces with age. This is normal
and to minimise the reduction the backlights are deactivated if the console hasn’t been
used for a preset time. The backlights are immediately reactivated when any front
panel button is pressed.
