HOW to Check P.C Boards | Mitsubishi Electronics MR-420R-W-A

6.2 HOW TO CHECK P.C BOARDS

MR-385R-A MR-420R-A MR-455R-A

MR-385R-A(NZ) MR-420R-A(NZ) MR-455R-A(NZ)

(1) Precautions

Unplug unit before checking

If the controller P.C. board box is opened with the refrigerator inside cooled, dew will form on the control board, causing trouble such as poor insulation.

The following cares must be taken when servicing.

1.	Be sure to unplug the power cord before servicing.
2.	Wipe away droplets on the control board box with dry cloth,
	and dry it up before setting a new controller P.C board.
(2) How to check the controller P.C board and vicinity.
The control board box can be checked without opening the box.
Measure the voltage and resistance using 8 connectors outside		How to check with connectors
the box.		How to check with connectors
1.	Check for 230/240V output during power on.	POWER ON

Make the pin No.7,9 of the 9 pins white connector as a common pin, and measure the voltage between the common pin and

another pin.

Make sure that 230/240V is output

Note: The room light always has 230/240V.

2.Check for "thermistor" output during power on. 5 pins white connector

Make the pin No.1 of the 5 pin white connector as a common pin, and measure the voltage between the common pin and another pin.

Make sure that 2-3 VDC is output.

POWER OFF

3.Check for weak current wiring during power off 5 pins white connector

Remove the connector, and measure the resistance across -No.1 pin and No.2 pin to confirm the continuity for DEF thermistor.

-No.1 pin and No.3 pin to confirm the continuity for the Freezer thermistor.

- 16 -

MR-385R-W-A, MR-385R-W-A(NZ), MR-455R-W-A(NZ), MR-455R-ST-A(NZ), MR-385R-ST-A(NZ) specifications

Mitsubishi Electronics has long been recognized for its innovative solutions in the realm of air conditioning and climate control. Among its impressive lineup are the MR-455R-W-A, MR-385R-ST-A, MR-420R-W-A(NZ), and MR-420R-ST-A(NZ) models, each designed to meet diverse cooling and heating needs while ensuring energy efficiency and user comfort.

The MR-455R-W-A is a versatile unit that stands out for its powerful cooling capacity, making it ideal for larger spaces. It is equipped with advanced inverter technology, which allows the compressor to operate at variable speeds depending on the cooling or heating requirements. This not only enhances energy efficiency but also ensures quieter operation, making the MR-455R-W-A a perfect choice for residential and commercial environments.

Similarly, the MR-385R-ST-A model offers a balance of performance and compact design. This unit is particularly suitable for medium-sized rooms and employs a range of smart features, including a programmable timer and a user-friendly remote control. Its energy-saving mode aims to reduce electricity consumption during off-peak hours, making it an eco-friendly option.

The MR-420R-W-A(NZ) is tailored specifically for the New Zealand market, emphasizing performance in diverse climatic conditions. This model incorporates Mitsubishi's sophisticated air filtration technology, effectively removing dust, allergens, and other pollutants from the air, contributing significantly to indoor air quality. With its sleek design and efficient operation, the MR-420R-W-A(NZ) is ideal for modern homes looking for both aesthetics and functionality.

In contrast, the MR-420R-ST-A(NZ) offers similar benefits but with a focus on reliability and durability. Its robust construction ensures it can withstand varying weather conditions, while the energy-efficient operation helps in minimizing utility costs. Both MR-420 models share a common feature – the ability to operate quietly, making them suitable for bedrooms or study areas.

Each model utilizes Mitsubishi's proprietary technologies aimed at maximizing energy efficiency and comfort. Features such as self-diagnosis capabilities, easy installation, and maintenance enhancements contribute to the overall user experience.

In conclusion, Mitsubishi Electronics has designed the MR-455R-W-A, MR-385R-ST-A, MR-420R-W-A(NZ), and MR-420R-ST-A(NZ) as reliable and efficient air conditioning units. With features focusing on energy conservation, indoor air quality, and user-friendly operation, these models cater to a wide range of customer needs and preferences.