ZIMO MX9V, Инструкция по эксплуатации

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Page 20 Track section module MX9
12. Replacing the EPROM
After powering down the system or disconnecting the MX9 remove the 3 Phillips screws holding the
Plexiglas cover (some versions only use the two front screws to hold the cover in place). Note the
position, with its index markings on the EPROM and the socket. The EPROM is removed from its lo-
cation (upper right corner) by using a screw driver placed underneath it and carefully lifting it up. Do
not bend the small pins.
Install the new EPROM with the index mark in the same position. Make sure that all pins are actually
inserted and none of them are bent!
13. Increasing the threshold for occupancy
detection
In some cases it may be necessary to increase the threshold of occupancy detection for selected
track sections by either raising the current flow above the standard value or decreasing the resistor
across axles (see page 3). A false occupancy indication due to dampness in a garden railroad may
be prevented with this measure. This may also be useful to prevent a wrong occupancy indication in
a return loop section controlled by an MX7 module.
Of course, raising the threshold of occupancy detection causes some vehicles with resistance axles
(without lighting or motor) not to be recognized anymore.
The modification is done for individual track sections at the MX9 board. Remove the board by un-
screwing cover and the threaded cover supports. An additional resistor is soldered to the appropriate
track section circuit.
The following drawing illustrates the position for installing the resistors of track sections 1A, 1B, 8A
and 8B, as an example. The top side of the board is shown but the resistors are soldered on the op-
posite side to the rectifier pins of the 8 main sections.
Trial and error determines the value of the resistors. For example, a 330 Ohm resistor doubles the
current flow required for track occupancy detection, which in turn cuts the value needed for the axle
resistor in half (e.g. at 20V from a 22k to a 11k resistor).
Smaller resistors installed to the board, such as 100 Ohm, 47 Ohm etc., will reduce the sensitivity
even further.
EPROM
Resistor added to
track section 1B
Resistor added to
track section 1A
Resistor added to
track section 8B
Resistor added to
track section 8A