Friday, March 06, 2026

DIY Series 101: Mitsubishi Mr Slim Aircond (MS-A10VD) Malfunction

Mitsubishi Mr Slim Aircond (MS-A10VD) Malfunction

Symptoms:

  • Indoor unit doesn't receive the signal from remote controller, the aircond is not turn on.
  • When the "Emergency Operation" switch is pressed, indoor unit operates.

Analysis:
  • Change new battery for remote controller. This is to make sure the battery is in good condition.
  • Put the remote controller in front of smartphone's camera, you should be able to see the IR LED is flashing purple or white light on your phone's screen. This confirms the remote is transmitting a signal, even if invisible to the naked eye.
  • Open up the indoor unit cover, look for manual switch. When the "Emergency Operation" switch is pressed, indoor unit operates. It means most likely the IR Receiver Board is malfunction. This is executed when the remote controller is lost, broken, or has dead batteries.
    • Operation Sequence (Common):
    • First Press: Starts a 30-minute test run (usually high fan speed, no temperature control).
    • After 30 Mins: Often shifts to a default COOL mode (approx. 25°C).
    • Subsequent Presses: Cycles between EMERGENCY COOL and STOP modes.
  • If repairing the receiver on the PCB board, look for 38kHz, standard 940nm 5mm IR Receiver Module (VS1838 / VS1838B / TSOP4838).
  • TSOP4838: Manufactured by Vishay, a major brand in electronics components. It is more expensive, roughly US$1.
  • VS1838 / VS1838B / HX1838: A generic or third-party manufactured component, frequently sold in hobbyist kits. It is significantly cheaper, sometimes just 14 - 20 cents.


Photos:

  • Emergency Operation Switch location

  • Mr Slim (MS-A10VD) Indoor Unit PCB & Receiver PCB Diagram
  • IR Receiver Module (VS1838 / VS1838B) inside Receiver PCB
    • Model: DH00L515
    • Replacement Part Number: E22 41G 329

  • Remove the screw caps of the panel. Then, remove the screws.
  • Open the holder, dismantle the Receiver Board from indoor unit


  • Simple IR Remote Tester (with battery)



Video:
  • Testing the old IR Receiver Module with Smartphone (Remote Control): TBA


[ Pending to dismantle from Mitsubishi Aircond ]
= To Be Update Later =


  • Testing the new TSOP4838 with Smartphone (Remote Control): OK


Costs Involved:
  • IR Receiver Module (TSOP4838): US$1.00 (bought from Element14)

Tools Required:
  • Received IR Receiver Module (TSOP4838) on 05/Mar/2026.
  • Pending for dismantle & fixing on Mitsubishi Aircond.
  • Hopefully it is solved after fixing.

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Thursday, March 05, 2026

DIY Series 100: LDNIO Extension Power Strip (SC4408) Malfunction

LDNIO Extension Power Strip (SC4408) Malfunction

The LDNIO SC4408 (also part of the Defender Series) is a heavy-duty power strip designed to support up to 8 devices simultaneously with 4 universal AC outlets and 4 USB-A ports. Newer version (SC4408C) comes with 2 USB-A ports + 2 USB-C ports (supporting PD20W).

  • Total Power: Supports up to 2500W at 250V (10A max), making it suitable for household appliances like computers and microwaves.
  • USB Output: Features 4 USB-A ports with a total output of 5V/3.4A (17W).
  • Cable: Equipped with a 2-meter heavy-duty power cord using a 33% thickened wire core for improved conduction and lower heat.
  • Material: Built with fireproof PC material that can withstand temperatures up to 850°C.
  • Overload Protection: A dedicated reset button automatically cuts power during an overload to protect connected electronics.

Symptoms:
  • All AC outlets unable to turn on.
  • Power strip failing to turn on even after you press the reset button.

Analysis:
  • Internal Fuse: Fuse at the 13A plug tested working fine
  • Broken Reset Mechanism: The reset button feels "mushy" or doesn't have a distinct "click" when pressed, the internal spring or contact point may have failed.
  • Appearance: No burning smells, smoke, or visible scorch marks on the housing.
  • Connectivity: Tested all AC outlets connected to incoming wires (L/N/E).

KYB8 Circuit Breaker: 

  • Compact thermal overload protector and circuit breaker primarily used for manual reset protection in electrical appliances and industrial equipment. It features a recessed reset button that pops out during an overload and must be manually pressed back in to restore the circuit.
  • The core of the breaker is a strip made of two different metals bonded together. These metals expand at different rates when heated.
  • Under normal conditions, these copper contacts are held together to allow current to flow through the device.
  • When current exceeds 10A, the resistance in the bimetallic strip generates excess heat (Joule heating). Because the metals expand differently, the strip begins to bend and breaking the circuit.
  • The external button "pops out" to indicate the trip. After the bimetallic strip cools and returns to its original shape, the user can manually push the button back in to re-latch the contacts and restore power.


USB Module:

  • Capacitors
    • 1500uF/10V: The flat top of the aluminum case becomes convex or domed.
    • 22uF/400V: No visible damage.
    • 4.7uF/50V: No visible damage.
    • Summary: Capacitor (1500uF/10V) malfunction

How a Bad Capacitor Affects the KYB8?

A capacitor (1500uF/10V) malfunction impacts the KYB8 breaker in following 2 main ways: 
  • Short Circuit (Immediate Trip): If the capacitor fails by shorting internally, it creates a path of very low resistance. This causes a massive, sudden surge of current to flow through the KYB8. Since the KYB8 is a thermal breaker, this high current quickly heats the internal bimetallic strip, causing the reset button to "pop" and cut power to protect the wiring.
  • Physical Wear and Tear: The KYB8 is a mechanical device. While it is designed to trip, repeatedly resetting a breaker that is tripping due to a faulty capacitor can wear out its internal spring mechanism and contact points. Over time, this can lead to the breaker becoming "broken" (unable to reset or failing to trip when it should).

Action To Be Taken:
  • Stop Resetting the KYB8: Repeatedly pushing the reset button while a capacitor is shorted can weld the internal contacts of the breaker or cause the capacitor to vent (pop/leak) aggressively.
  • Replace the Capacitor: You need a replacement with the same capacitance (1500uF) and a voltage rating of 10V or higher (using a 16V or 25V capacitor is a common "upgrade" for better durability, provided it fits the space).
  • Check the KYB8: Once the capacitor is replaced, if the KYB8 still trips or feels "mushy" when you press it, the breaker itself may have been heat-damaged by the faulty capacitor and should also be replaced. 

Cost Involved:

Tools Required:
Summary:
  • Just placed order for the replacement parts on 05/Mar/2026. 
  • Pending for new parts delivery and implementation.
  • Hopefully it is solved after fixing.

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Wednesday, March 04, 2026

Travel: Flight Info for Student Exchange Trip to Nagoya, Japan.

Flight Info for Student Exchange Trip to Nagoya, Japan


This blog is to keep a record on the process to secure flight ticket at most suitable time for best possible price.

My son's secondary school planned a student exchange trip to Toyohashi (Aichi Prefecture). The nearest airport is Chubu Centrair International Airport (NGO) which is located at Nagoya.

Due to recent political issue between China and Japan, it was announced that China cancels all flights on 49 routes to Japan | The Star (27/Jan/2026). Thus, flight selection had been limited to only several airlines except those from China. With such limitation, Singapore Airlines will be the one of the best option, and it is expected the fare will continue to increase if the political issue continues as it is. On the other hand, school teacher is looking for ticket purchase directly via travel agency as alternative option.


1) Proposal #1

Target Date: 22/May/2026 (Fri) ~ 30/May/2026 (Sat) - 9D8N
Target Flight: Singapore Airlines
Departure: Penang International Airport (PIA)
Arrival: Chubu Centrair International Airport (NGO) 
  • Flight Fare Monitoring:
    • 12/12/2025: RM3,283
    • 03/02/2026: RM3,841
    • 04/02/2026: RM3,758
    • 09/02/2026: RM3,757
    • 10/02/2026: RM4,117
    • 23/02/2026: RM4,476


Pros:
  • Shortest flight time, longer stay time in Japan.
Cons:
  • Price kept increasing from day to day.

2) Proposal #2

Target Date: 23/May/2026 (Sat) ~ 31/May/2026 (Sun) - 9D8N
Target Flight: Singapore Airlines
Departure: Penang International Airport (PIA)
Arrival: Chubu Centrair International Airport (NGO) 
  • Flight Fare Monitoring:
    • 10/02/2026: RM3,757
    • 23/02/2026: RM3,756


Pros:
  • Cheapest price at this moment (23/Feb/2026)
Cons:
  • Longer transit time at Singapore Changi Airport when heading to Japan. However, possible of 2.5-hour guided FREE Singapore Tour during the long hours transit.

3) Proposal #3

Target Date: 22/May/2026 (Fri) ~ 31/May/2026 (Sun) - 10D9N
Target Flight: China Airlines
Departure: Penang International Airport (PIA)
Arrival: Chubu Centrair International Airport (NGO) 
  • Flight Fare Monitoring: 
    • 23/02/2026: RM3,408 (via Travel Agency)

Pros:
  • Day flight. Travelers who transit through Taoyuan International Airport and enter Taiwan for a stay of up to 24 hours during their layover will receive a gift voucher worth NT$600. The vouchers can be redeemed across airport restaurants, duty-free outlets, souvenir shops, and retail stores.
Cons:
  • Layover 2-night (to/fro) at Taoyuan Airport. Need to pay additional for 2-night stay at airport hotel (for 2-night, twin sharing basis).

Conclusion:
  • Majority voted to proceed on Proposal #3 as we do not know if the flight fare will further increase or not. Secure a seat earlier with China Airlines save us from future uncertainty. 
  • Total payment of RM3,848 (Flight RM3,408 + Hotel RM440).

Travel Insurance




Transit @ Taiwan: "Enter Taiwan, Enjoy a Gift!” Campaign
  • The "Enter Taiwan, Enjoy a Gift!” campaign will open for online registration at 12:00 PM on November 1, 2025, and will run until October 31, 2026. Specifically designed for transit travelers, the campaign offers tangible incentives that encourage international visitors to explore the airport's unique shops and enjoy Taiwanese delicacies during their layovers. Through this effort, the Tourism Administration aims to enhance Taiwan's international visibility and attract return visits from transit passengers.
  • Travelers holding a non–Republic of China (Taiwan) passport who transit through Taoyuan International Airport and enter Taiwan for a stay of up to 24 hours during their layover will receive a gift voucher worth NT$600. The vouchers can be redeemed across airport restaurants, duty-free outlets, souvenir shops, and retail stores.
  • Travelers can register their basic information on the campaign website. Upon arrival at Taoyuan International Airport, they can present their passport and onward international boarding pass at the Taiwan Tourism Administration's Visitor Service Centers (located in Terminal 1 or Terminal 2) to receive a NT$600 shopping voucher.

Nagoya Chubu Centrair International Airport (NGO)
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Monday, March 02, 2026

Wardrobe Rail Bracket Temporary DIY Solution

Wardrobe Rail Bracket Temporary DIY Solution & Final Fixing

Early morning found out the rail brackets inside wardrobe was broken. 


This is my DIY temporary solution while waiting to buy replacement wardrobe rail brackets. It looks quite solid, should be possible to use for at least few days.

Steps:

  1. Look for 2pcs of PET Bottles cap (choose harden type with better thickness). 
  2. Check the original screw location, use mini hand drill (Portable Screwdriver Drill Set) to make 2 holes.
  3. Use blade to cut an opening at the cap (top side when use as bracket) for slotting in the oval rail later.
  4. Screw the two bottles cap at each side of the wardrobe with 2 screws.
  5. Upon received the new brackets, removed the bottles cap and replaced with new brackets.


Tools Required:


Cost Involved:

Repair Logs:
  • 02/03/2026: Temporary fixed with PET Bottles Cap
  • 02/03/2026: Placed order for new rail brackets
  • 03/03/2026: Received new rail brackets, installed with new brackets.


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Wednesday, February 25, 2026

DIY Series 99: Midea Water Heater MWH-38P5 Not Working

Midea Water Heater MWH-38P5 Not Working (No Power at All)


Symptoms:
  • No power at all when switched ON.
  • Tested incoming supply at water heater terminal block is working.
  • Suspect the Main Control Board malfunction.



Board Analysis:

1) Relay (MPQ4-S-112D-A)


  • Testing the MPQ4-S-112D-A (a 12VDC, 30A 4-pin normally open relay) requires a multimeter and a 12V power source. 
  • Identify the Pins
      • The relay has 4 pins. 
      • Coil Pins: These receive the 12V signal to activate the relay.
      • Switch (Load) Pins: These are "Normally Open" (NO), meaning they only connect when power is applied to the coil.
    • Coil Resistance Test (Multimeter Only)
      • Use this to check if the internal electromagnet is intact. 
      • Set your multimeter to the Resistance (Ω) setting.
      • Measure across the two coil pins.
      • Result: A healthy MPQ4-S-112D-A coil should read approximately 160Ω (±10%) Virtual Expo. A reading of "OL" (infinite) or 0Ω indicates a dead coil. 
    • Audible Click Test (12V Power Source) 
      • Listen for the mechanical movement of the switch. 
      • Apply 12VDC to the coil pins.
      • Result: You should hear a distinct "click" sound as the internal contact moves. If it doesn't click at ≥9V, the relay is seized or faulty. 
    • Load Continuity Test (Power + Multimeter)
      • This confirms the switch actually closes and conducts electricity. 
      • Set your multimeter to Continuity (Beep) or Resistance (Ω).
      • Place probes on the two load pins (the switch side).
      • Without Power: The meter should show "OL" (no connection).
      • With 12V applied to Coil: The meter should beep or show nearly 0Ω. If the relay clicks but the resistance remains high, the internal contacts are likely burnt or oxidized.
  • Summary: Tested the relays (both units) are working fine.
2) Capacitor

  • Testing the capacitor with a multimeter.
    • EC1: Malfunction (OL)
    • EC2: Working
    • EC3: Working
  • Summary: EC1 need to be replaced with new part.
3) Voltage Regulator


  • Set the multimeter to Resistance (Ω) or Continuity Mode. 
    • Regulator: U1 (UTC7805)
      • Input to GND (Pin 1 to Pin 2): Should not show a short circuit (0Ω) or constant beep).
      • Output to GND (Pin 3 to Pin 2): Should not show a short circuit.
      • Input to Output (Pin 1 to Pin 3): Should not show a direct short, though some resistance is expected. 
  • Summary: Tested the regulator (UTC7805) is working fine.
4) Other Parts (Diode / Resistor / Optocoupler)

  • Testing the components with a multimeter.
    • Diode: D5/D6/D7/D8/D9/D10 (~0.5V)
    • Zener Diode: ZD1 (~0.7V)
    • Resistor: R31 (~390kΩ), R37 (~10Ω) 
    • Optocoupler: U2 (Sharp PC817)
      • Check Pin 1 & 2 (multimeter set to Diode Mode)
      • Forward (1: Red, 2: Black): ~1.0V
      • Reverse (2: Red, 1: Black): OL
  • Summary: All other parts above are working fine.
5) Transformer (240VAC to 12VAC)
  • Testing the components with a multimeter
  • Testing a 240VAC to 12VAC step-down transformer involves checking for structural integrity, measuring coil resistance to ensure they are not "open" or broken, and verifying the output voltage while under power. 
  • Transformer (Dazhong Electronic, Model: EI35-115200, 200mA) 
    • Primary Coil: OL / High Resistance (>10MΩ) (typically 500Ω and 2kΩ)
    • Secondary Coil: Low resistance (7.3Ω) 
    • Isolation: OL
    • Output Voltage: Not tested (due to safety concern)
  • Summary: Suspect transformer primary coil is broken

Analysis:

A failure of the 1000µF capacitor is directly related to transformer and power supply issues in the Midea MWH-38P5. In this unit, the 1000µF capacitor typically serves as the primary filter (smoothing) component for the low-voltage DC power supply generated by the transformer.

If this 1000µF capacitor fails, it can cause the following chain of events:
  • Voltage Ripple and Instability: A 1000µF capacitor's main job is to "smooth" the pulsing DC voltage from the rectifier into a steady flat line. If it fails (becomes "open"), a large ripple voltage is applied directly to the control board, which can cause erratic behavior or damage sensitive semiconductors.
  • Overloading the Transformer: If the capacitor shorts internally, it creates a direct path to ground for the transformer’s secondary winding. When a transformer is forced to work against a failing filter circuit (like a bad 1000µF cap), the heat builds up in the primary winding. Because the primary wire is hair-thin, it acts like a fuse and breaks.
  • System "Stuttering": A weakened capacitor (lowered capacitance) may cause the unit to turn on and off rapidly as the voltage drops every time a relay tries to engage, leading to the "unstable power" symptom often reported by users.

Parts Sourcing:
  • Relay (MPQ4-S-112D-A) - for backup purposes only


Parts Replacement:
  • Solder the new capacitor (1000uF/25V) on board


  • Replace with new transformer (12VAC, 350mA)
    • Left: After received new transformer, found out the Pin-to-Pin distance is 2.0cm (possible to modify pins location)
    • Right: Unable to source transformer (unlisted by seller) with Pin-to-Pin distance is 1.5cm
    • Modified the transformer pins in order able to fit into PCB existing footprint (thru holes)
    • Check the transformer's pin alignment (after modification) on board
    • Soldered new transformer (after modification) on board
    • Tested the old Main Control Board is working on Midea Water Heater MWH-38P5


New Main Control Board Replacement:
  • In parallel, proceed to source the new board directly, the new board will be kept for future used.

Summary:
  • Main Control Board is suspected malfunction due to failure of the 1000µF capacitor which is causing transformer (primary winding) coil broken (open circuit).
  • After fixing done (changed new 1000uF/25V capacitor and equivalent 12VAC 350mA transformer) on old Main Control Board, the old board is now working well.
  • Midea Water Heater MWH-38P5 had been fixed (with old Main Control Board) and resume back to normal.
  • In summary, I am now having both old and new Main Control Board in working condition.

Tools Required:

Cost Involved:

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