Maytag Built-in Refrigeration, Руководство пользователя

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Servicer’s Note
This type of power supply has very sensitive short circuit protection. Should an excessive
load be detected on one of the power supply lines the DC supply will shut down. After a
short off time the power supply will attempt to restart. If the short is still present on the
DC power line it will shut off again and attempt to restart. This cycling will make the
supply appear to be pulsing. The DC voltage may be present for a very short time and
then it will disappear again. It is hoped that this sensitive protection will help to prevent
damage to the DC supply.
Diagnosis to locate the excessive load is a trial and error process. The first step is to
verify that the power supply is indeed capable of providing the needed voltages. With the
power disconnected from the appliance (Main power switch off), unplug JP11. If the
power supply resumes normal operation, you have verified that the power supply is
capable of operation. Disconnect the main power.
Reinstall JP11 and unplug JP7 and JP9. Reinstate power. If the DC supply resumes
normal operation you have eliminated the Main Control Board as the source of the
excessive load on the power supply. Disconnect power and reinstall JP9. If the power
supply continues normal operation you have eliminated the display as the source of the
excessive load.
JP7 supplies power to the CZT modules, the dispenser, the electronic damper and both
the evaporator and fresh food fans. Plugging this in will put you back where you had
started. You will need to isolate the possible source of the excessive load to progress
further. There are two options to progress with from here.
One method would be to disconnect each individual component from the harness and add
them in one at a time. This would require considerable disassembly of the product and
would not be an efficient method to isolate the failed component. The second method
would involve resistance checks from JP7 itself. Checking for shorts off of the harness
can be a quick process to determine what further actions are required. Remember that
with JP7 disconnected, the DC ground is disconnected from these components so all
resistance checks would need to be taken between two pins in the connector itself.
Circuit Board and Connector Locations