Johnson Systems DE90-3000 Series Retrofit Control System User Manual
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• Disconnect the JP2 connector labeled “TO LOCAL PANIC BRACKET” from the backplane.
The entire panic bracket can now be removed. There are four (4) #10-32 mounting nuts
securing the bracket in place that need to be removed using a 3/8" nut driver. Once the nuts
are removed, the bracket can be pulled out and set aside.
• Disconnect all of the field wiring connected to the top connectors on the backplane (JP1,
JP6, JP10 thru JP16 and JP18). These cables may be reused in some applications. Any
unused cables should be coiled up and wire-tied. Carefully set them aside inside the rack
and keep them isolated from any AC line voltage.
• Remove the Analog Input connectors (if applicable) from the top of the Processor Module.
These cables may be reused in some applications. Any unused cables should be coiled up
and wire-tied. Carefully set them aside inside the rack and keep them isolated from any AC
line voltage.
• Remove the two (2) screws located on each end of the processor module.
• Slide the processor module partially out (approximately 3" (75mm)) until you have enough
space to disconnect the control cables on the right-hand side (if applicable) and 3-Phase AC
Power Cable on the left-hand side.
Some of the control cables may be reused in some applications. Any unused cables should
be coiled up and wire-tied. Carefully set them aside inside the rack and keep them isolated
from any AC line voltage.
The 3-Phase AC Power Cable must be left intact and reconnected to the backplane on the
DE90-3000 retrofit. Do not remove any of the wires from the connector.
• Slide the processor module out completely and set it aside.
• Disconnect the OEM fan power cables from JP5 connector located on the lower right-hand
side of the backplane. You will need a small flat head screwdriver to loosen the connections
and pull the wires out. The OEM fan power cables will need to be reconnected to the
2-position breakaway connector on the backplane of the DE90-3000 retrofit.
Inspect the fans and make sure they spin freely. Overheating of the dimmer modules is one
of the main causes of failure. Replacement fans are available from JSI upon request.
• Disconnect the OEM thermostat and power supplies cable from the JP8 connector. The
wires and connector must be left intact and reconnected to the backplane on the DE90-3000
retrofit. Do not remove any of the wires from the connector. There is an OEM thermostat
located at the top of the rack and is wired in via this cable and connector. The thermostat
is a normally closed contact and opens at 185°F ±7°F (85°C ±4°C). The thermostat must
be left intact and operational for the DE90-3000 retrofit to function properly. Replacement
thermostats are available from JSI upon request. There are two (2) OEM 12 Volt DC power
supplies located on right-hand side of the dimmer rack. The power supplies are used to
power the 24 Volt DC fans. The power supplies must be left intact and operational for the
DE90-3000 retrofit to function properly. Replacement power supplies are available from JSI
upon request.
• Disconnect the two (2) OEM SSR control cables from the JP3 and JP4 connectors. Note
that the small 36" DE90 dimmer racks may only contain one (1) OEM SSR control cable
connected to JP3. Do not pull on the wire to disconnect. Carefully apply pressure to the
connector itself with either your fingers or preferably a small flat head screwdriver. Do
not mix up the cable order or polarity. The wires and connector must be left intact and
reconnected to the backplane on the DE90-3000 retrofit.
• The backplane should now be free and clear of any connections. Unscrew the ten (10) #6-32
x 1/4" mounting screws. Remove the backplane from the dimmer rack and set it aside.
• All of the electronics out of the dimmer rack present a great opportunity to do some
preventative maintenance. The rack should be thoroughly cleaned, vacuumed and sprayed
out using compressed air. All of the AC line and load connections should be inspected and
tightened if necessary.