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REPAIR
TIPS FOR NRI COIN MECHS
NRI G.13.1002 (Side Entry), NRI G.13.0004 (Top
Entry-Pinball type).
A very popular coin mech, which can be
programmed to accept 6 different coins and has six individual coin
outputs. Each valid coin will produce single pulse (100ms -
programmable, switch to ground, open collector) on the appropriate coin
output (channel = coin output). Channels, which accept unwanted coins
can be easily disabled by the Dip Switch located under the side cover.
For programming or diagnostics, special computer software is used and
the coin mech must be connected to a computer via RS232 interface.
REPAIR TIPS
The most common faults when the coin
mech stops accepting coins.
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The blue surface mount capacitors on the inner
side of the pcb dried out, replace them with tantalum type caps.
You can measure pin 19 of the CPU (reference voltage). It should
be 2.5V if the caps are okay. Higher voltage (2.6V or near)
means problem with the caps.
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There are 3 coils in the main plate (the plastic
body) and 3 coils in the "door" to measure the coin.
Check them for continuity. It is best to check the door coils at
the end of the ribbon cable (pcb side). If open circuit, most
likely the flat cable itself is damaged. The main plate coils
can sometimes be fixed. The coil wire is usually broken near the
solder terminal and may be carefully reconnected. Otherwise the
whole main plate needs to be replaced. You don't need to remove
the PCB to measure the main plate coils.
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The solenoid operating the reject gate can be
open circuit. Also make sure that the plunger operates freely.
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The opto switch operated by the reject
button may be obstructed or faulty. This opto is usually
not used, it can be removed from the circuit, however you need
to short out the two PCB pads for the LED and also the pads
for the phototransistor.
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There is an added quarter watt resistor from the
inner side of the PCB (sometimes protruding at the top of the
mech). This resistor can be broken off due to physical abuse.
Reconnect it.
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