Danfoss MCD 500 Series User manual

MCD500 PCB Replacement MCD 500 PCB Replacement - Instructions
MI.17.F1.02 - VLT®is a registered Danfoss trademark Page 1/5
MCD 500 PCB Replacement - Instructions
Overview
This document describes how to replace the LCP (Local Control Panel) and main control PCB in MCD 500 soft
starters (all models).
N.B.!
Many electronic components are sensitive to static electricity. Voltages so low that they cannot be felt,
seen or heard, can reduce the life, affect performance, or completely destroy sensitive electronic
components. When performing service, proper ESD equipment should be used to prevent possible
damage from occurring.
Instructions
Remove all wiring and links from the soft starter before dismantling the unit. Disassemble the unit according
to the instructions below.
After reassembling the unit, apply control voltage and check that the welcome screen displays correctly.
1. Models MCD5-0021B ~ MCD5-0105B
Remove the top cover and terminal blocks from
the starter. Undo the 5 x Torx screws holding the
top plastic in place. Remove the top plastic.
Lift off the LCP and main control PCB assembly.
Label each SCR firing loom with the number of the
corresponding phase terminal on the main control
PCB, then unplug the looms. Unplug the
thermistor, fan (on selected models) and CT wires
from the main control PCB. Remove the existing
LCP and main control PCB and replace with the
new LCP/PCB.
Plug in the looms, replace 5 x Torx screws, top
cover and terminal plugs.

MCD 500 PCB Replacement - Instructions MCD500 PCB Replacement
MI.17.F1.02 - VLT®is a registered Danfoss trademark Page 2/5
2. Models MCD5-0131B ~ MCD5-0215B
Remove the top cover and terminal blocks from
the starter. Undo the 4 x Torx screws holding the
top plastic.
Tilt the top plastic to the right to expose the wiring
looms. Label each SCR firing loom with the number
of the corresponding phase terminal on the main
control PCB, then unplug the looms.
Unplug the thermistor, fan and CT wires from the
main control PCB. Undo the 4 x Torx screws from the model PCB
support bracket and set aside.
Remove 4 x Torx screws from the bypass driver
PCB, slide out to the right and set aside. Remove 7 x Torx screws from the main control PCB
and set aside.
Replace the PCBs, plug in the looms, top plastic,
top cover and terminal plugs.

MCD500 PCB Replacement MCD 500 PCB Replacement - Instructions
MI.17.F1.02 - VLT®is a registered Danfoss trademark Page 3/5
3. Model MCD5-0245C
Remove the top cover and terminal blocks from
the starter. Undo the 4 x Torx screws holding the
top plastic.
Tilt the top plastic to the right to expose the wiring
looms. Label each SCR firing loom with the number
of the corresponding phase terminal on the main
control PCB, then unplug the SCR firing looms
Unplug the thermistor, fan and CT wires from the
LCP and main control PCB and set the top plastic
aside.
Undo the 4 x Torx screws from the model PCB
support bracket and set aside.
Unplug the header connector from the main
control board and set aside.
Remove 7 x Torx screws. Replace the LCP and main
control PCB assembly. Replace the 7 x Torx screws
Replace the header connector. Replace the model board, check that the header
connector pins line up with the main control PCB
below.

MCD 500 PCB Replacement - Instructions MCD500 PCB Replacement
MI.17.F1.02 - VLT®is a registered Danfoss trademark Page 4/5
Reconnect the wiring looms. The SCR firing loom
will align with the relevant number of the
corresponding phase terminal on the main control
PCB. Take note of the thermistor wiring (grey/red)
to the right, and fan wiring (black/red) to the left
of the board. (The order of the thermistor and fan
plugs is not critical).
Replace the top plastic, top cover and terminal
plugs.
4. Models MCD5-0360C ~ MCD5-1600C
Remove the top cover and terminal blocks from
the starter. Undo the 4 x Torx screws holding the
top plastic.
Tilt the top plastic to the right to expose the wiring
looms. Label each SCR firing loom with the number
of the corresponding phase terminal on the main
control PCB assembly and unplug the SCR firing
looms.
Unplug the thermistor, fan and CT wires from the
LCP and main control PCB assembly. Undo the 4 x Torx screws from the model PCB
support bracket and set aside.

MCD500 PCB Replacement MCD 500 PCB Replacement - Instructions
MI.17.F1.02 - VLT®is a registered Danfoss trademark Page 5/5
Unplug the header connector from the main
control PCB and set aside. Remove 7 x Torx screws. Replace the LCP and main
control PCB assembly. Replace the 7 x Torx screws.
Replace the header connector.
Replace the model board, check that the header
connector pins line up with the main control PCB
below.
Replace the PCBs, plug in the looms, and replace
the LCP, top cover and terminal plugs. Take note
of the thermistor wiring (grey/red) to the right,
and fan wiring (black/red) to the left of the board.
Replace the 4 x Torx screws to secure the top
plastic and replace the top cover and terminal plugs.