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.
• 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:

• Capacitor 1000uF / 25V

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

• Transformer (12VAC, 350mA) - nearest specs available

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 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:

• New Main Control Board (for Model MWH-38P3 / MWH-38P5)

• 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:

• Screwdriver
• Multimeter
• Soldering Tools
• Cutter

Cost Involved:

• Capacitor 1000uF / 25V (2pcs): US$0.35
• Relay (MPQ4-S-112D-A, 2pcs): US$2.50
• Transformer (12VAC, 350mA): US$5.00
• New Main Control Board: US$20 ~ US$25

DIY Series 98: Joven Water Heater SA10E Not Working

Joven Water Heater SA10E Not Working

The Joven SA10E (3.6kW) is an instant water heater that uses a complex safety and control circuit to handle its 15A current. It does not wire a 10A thermostat directly to the heater; instead, it uses a PCB (Printed Circuit Board) with an EELS (Electronic Earth Leakage Sensor) to manage the switching safely. 

Joven SA10E Circuit Overview

The circuit for a 3.6kW Joven heater typically follows this path: 

• Main Power Inlet: 240V AC power enters through a 20A double-pole switch on your wall.
• EELS (Safety Board): Both Live and Neutral wires pass through a double-pole EELS system. If it detects a leakage of more than 10mA, it instantly cuts power.
• Flow Sensor (SFS): A magnetic sensor detects water flow. The heater will not activate unless water is flowing, preventing the element from burning out.
• Stepless Electronic Power Control: A knob on the front controls a Triac on the PCB. This electronic component acts as the "acting" switch, varying the power to the heater element based on your temperature setting.
• Thermostat with Safety Cut-Out: This is the "high-limit" thermostat. If the water exceeds a safe temperature (e.g., due to a PCB failure), it trips to prevent scalding and fire. 

Symptoms:

• No power at all when switch ON. Sometimes EELS (Green LED) will be ON for a while, then turn OFF again. The heater (Red LED) will not be turn ON, even temperature control knob is turn with water flow in.
• When press "Test/Reset" button, the EELS (Green LED) will be turn ON and then turn OFF immediately.
• Suspect the Main Control Board or thermostat malfunction.

Debugging:

• If you hear a mechanical click inside the unit when you press the "Reset" button, it confirms that either the EELS relay or the high-limit thermal cut-out has physically re-engaged.
• Since the EELS light is still staying off despite that click, here is the diagnosis:
• If the thermostat fails, it breaks the circuit completely. No power reaches the EELS board, so the light stays off.
• Use a multimeter to check for continuity across the thermostat. If it's "open" even after clicking, it must be replaced.

Findings:

• Checking the Main Control Board (Power Supply Board), found no issue.
• Trial and error to replace thermostat, see if it is the culprit. After changing thermostat, the Joven Water Heater (SA10E) resume back to normal.

Parts Sourcing:

• Found the thermostat written ATT S102, try to look for the original parts, but not available for sale at online store.

• Found another thermostat, KSD303 having same shape and size. Rating at 250VAC/10A, 150°C.

• Use Google Gemini to check compatibility. For a 10A application at 250VAC, both the ATT S102 and KSD303 are technically suitable, as 10A is a standard rating for both series. At this current level, the choice depends primarily on whether you need a direct manufacturer-specified replacement (ATT S102) or a more widely available, generic industrial alternative (KSD303)

• While some manufacturers may use a 10A thermostat in a 3.6kW water heater, it is only safe if it is part of a relay or contactor system. In such a setup, the 10A thermostat does not carry the full 15A–16A load itself but instead acts as a "trigger" for a higher-rated switching device. 

Photos:

• Joven Water Heater (SA10E) - bought in Year 2017

• Thermostat located at the top of the water tank

• Remove the thermostat (ATT S102)

• Replace with new thermostat (KSD303)

Tools Required:

• Multimeter
• Screwdriver
• Hex wrench (to remove thermostat)

Cost Involved:

• Thermostat (KSD303): US$1

How a 10A Thermostat Works with a 3.6kW Heater?

If your water heater was originally built with a 10A thermostat, it likely operates in one of the following ways:

• Indirect Switching: The 10A thermostat controls a contactor or relay that is rated for 20A or 25A. The contactor handles the heavy 15A current, while the thermostat only handles a very small control current.
• Safety Cutout Only: Some 10A thermostats are used strictly as a secondary safety limit (high-limit switch) designed to trip and stay off in an emergency, rather than cycling the heater on and off daily.
• Low-Voltage Controls: In modern digital or "smart" systems, the thermostat may operate on low voltage (e.g., 5V or 12V) to send a signal to an electronic board, which then switches the main power.

In the Joven SA10E, the 10A thermostat is likely used as a secondary safety trigger on the control board:

• It does not carry the 15A load directly.
• It sends a signal to the PCB/Relay/Triac to cut off the main power if things get too hot. 
• Typical thermal cut-out profile:
• Standard Thermostat (Auto Cut-Off) @ 55°C: Anti-Scald protection
• Manual Cut-Out @ 80°C–95°C: Secondary safety limit
• Thermostat Max Rating @ 150°C: For dry-burn protection in heating elements

Info: Intermittent Connection on Xiaomi / RedMi Phone (SIM Card Shows No Service / No Data)

Intermittent Connection on Xiaomi / RedMi Phone (SIM Card Shows No Service / No Data)

Target Phone:

• Xiaomi Redmi Note 13 5G (OS: HyperOS 2.0.209.0, Android 15)

Symptoms:

• Phone SIM card suddenly not detected, no service / connection
• It happened only on SIM card Slot #1, no issue on SIM card Slot #2

Step 1: Quick Fixes (Simple Check)

• Restart Phone: A simple restart often fixes temporary glitches.
• Airplane Mode: Turn Airplane Mode on, wait a few seconds, then turn it off to refresh network connection.
• Check Mobile Data Setting: Go to Settings > Mobile networks > Mobile data and ensure its toggled ON.
• Preferred Network Type: In the same menu, select Prefer LTE/5G (or 4G/5G) as the preferred network type. 

Step 2: Hardware & SIM Checks

• Reinsert SIM: Power off, eject the SIM tray, check the SIM for dirt/damage, clean it gently with a dry cloth, and reinsert it properly.
• Test SIM in Another Phone: Insert your SIM into another phone; if it still has no data, the SIM card is likely faulty.
• Inspect SIM Slot: Look for dust or debris in the phone's SIM slot. 

Step 3: Advanced Troubleshooting

• Reset Network Settings: Go to Settings > More connectivity options > Data usage > Reset Wi-Fi, mobile networks, and Bluetooth. This reset saved Wi-Fi, mobile data, and Bluetooth settings without erasing personal data.
• Check for Updates: Ensure your phone's operating system is up-to-date (Settings > About phone > System update).
• Developer Options: Go to Settings > About phones > OS version, continuous clicking on "OS version" to activate the Developer mode. Then, go to Settings > Additional Settings > Developer options to set “Mobile Data Always Active”
• Enter Secret Code: Dial *#*#64663#*#* to enter Factory Diagnostic Tool and proceed hardware test to check whether the SIM Cards are working or not. 

Step 4: Ultimate Weapon (Worst Case)

• Factory Reset: As a last resort, back up data and perform a factory reset (Settings > About phone > Factory reset). 
• Get Help from 3rd Party: If these steps do not resolve the issue, it may be necessary to contact your service provider (carrier) for SIM card replacement or visit a professional repair service for further assistance.

My Final Solution:

• Debug done using Step 1, Step 2, and even Step 3, but not solving the issue.
• Suddenly I thought of eject the SIM card tray and bending it slightly, then re-insert it into the phone. This simple step indeed solved my issue. The intermittent connection is no longer happened. It is now having stable mobile data connection.

Xiaomi Secret Code Listing

Travel: Pangkor Island 2D1N @ Govt RPP (Rumah Peranginan Persekutuan)

Pangkor Island 2D1N

Pangkor Island (Pulau Pangkor) is a small, charming island off Malaysia's west coast in Perak, known as a laid-back tropical getaway with beautiful beaches, clear waters, rich history (Dutch Fort, temples, floating mosque), local culture (fishing villages), and budget-friendly charm, attracting both locals and international tourists seeking relaxation and simple pleasures like snorkeling and island exploration. 

Pasir Bogak and Teluk Nipah are popular beaches on Pangkor Island, known for watersports and relaxation, with Teluk Nipah being livelier, offering snorkeling, swimming, and food stalls, while Pasir Bogak is great for sunsets and calmer vibes; nearby Giam Island is a prime spot for snorkeling and island hopping, accessible via local boat tours. 

You can walk to Giam Island (Pulau Giam) from Pangkor Island's Teluk Nipah during low tide via a sandbar (dragon spine), but it requires caution as you'll walk on slimy, potentially sharp coral and rocks, so wear water shoes/sandals, watch for sea cucumbers and stingrays. Check the tide schedule for Pangkor Island before you go, to avoid getting stranded by the rising tide.

Pangkor Island, designated duty-free in 2020, offers tax-free shopping on items like chocolates, perfumes, and local dried seafood, boosting tourism with deals on goodies and souvenirs, though liquor isn't included; it's a great spot for beach lovers and shoppers seeking bargains alongside its natural beauty and fishing village charm. However, alcohol, tobacco, and motor vehicles remain excluded under these exemptions and will incur standard duties.

To purchase most duty-free goods on Pangkor Island and carry them out, a visitor needs to stay for a minimum of 24 hours. Proof of stay, such as a ferry or flight ticket, may be required. 

Accommodation @ Pangkor Island:

The Pangkor Island Federal Rest House / RPP (Rumah Peranginan Persekutuan) Pulau Pangkor is a government accommodation facility managed by the Property Management Division (BPH) of the Prime Minister's Department for civil servants to enjoy budget holidays in popular holiday locations such as Pangkor Island, offering hotel / resort style accommodation at special prices to encourage work-life balance, with a concept of recreation and welfare for civil servants.

Reservation / booking can be done via online portal at ProMIS, eligibility is based on your job position grade and limited to a maximum of three (3) bookings per year for an overnight stay at any Federal Rest House (RPP). 

In the past, we had tried at Cameron Highlands (most popular destination), Bukit Fraser, and Morib. This time, we would like to experience it at Pulau Pangkor, thus we had made reservation for 2026 CNY school holiday, at the rate of RM200/night for a 4-room bungalow (max up to 6 adults + 4 children).

Ferry Service:

• Via Marina Island Jetty (~10min): 
• Pangkor Ferry | Time Schedule | Buy Ticket | Parking Fee (RM23/day)
• RedBus
• Via Lumut Jetty (~33min):
• EasyBook | Parking Fee (RM15/day)

Transportation @ Pangkor Island:

Rental services are available at Pangkor Jetty, as well as in hotel areas at Teluk Nipah and Pasir Bogak.

Pink Taxi Fare Rates on Pangkor Island (As at Jan 2025)

• Pink Taxi / Van (for reference only; actual fares may vary): 
• Jetty to Pasir Bogak
• 1-4 persons: RM12.00
• 5 persons & above: RM20.00
• Maximum: 10 persons
• Jetty to Teluk Nipah
• 1-4 persons: RM18.00
• 5-6 persons: RM25.00
• 7-10 persons: RM30.00
• Island Tour (Pink Taxi Charter)
• RM80.00 – RM100.00 for the first two hours
• RM30.00 per additional hour
• Car: 
• Starting from RM90 per day, depending on the season and vehicle type.
• Motorcycle:
• Starting from RM40 per day.
• Bicycle:
• Starting from RM15 per day.

Proposed Itinerary:

Day#1

• 09:00: Depart from Sitiawan
• 09:30: McD DriveThru Seri Manjung
• 10:00: Reach Marina Island Jetty Complex
• 10:45: Ferry depart from Jetty
• 10:55: Reach Pangkor Jetty
• 11:00: Shopping @ Pangkor Town
• Laris Duty Free or Sun Duty Free or The Island Shop or Keok Family
• Billion Value Mart (to buy snacks & drinks)
• 12:30: Lunch
• Kedai Kopi Lee Meng Yong (李明榮茶室) or
• Island Culture Cafe (潮人馆) or etc...
• 13:00: Round Island Trip (2 ~ 3 hrs)
• Dutch Fort
• Masjid Al-Badr / Pankor Sea
• Fu Lin Kong Temple
• Tau Fu Fa (木桶豆腐花) (10:00 - 14:00) (optional)
• Masjid Al Khairiyah (Chinese Muslim Mosque)
• Eng Seng Pangkor Foods or Hai Seng Hin Pangkor
• Lin Je Kong Temple
• Teluk Nipah Beach
• Pangkor Turtle Conservation and Information Centre (optional)
• 15:30: Check-In @ RPP Pangkor
• 18:00: Pulau Pangkor Landmark / Pasir Bogak Beach 
  
• 19:00: Dinner @ Coco Restaurant or 小李小炒 or Portugal Style BBQ Fish or Bu Dao Zai (不倒仔美食阁)
• 20:00: CK Duty Free / CK Supersave Mart (Pasir Bogak)
• 21:00: Return to RPP Pangkor
• 22:00: Zzz

Day#2

• 07:00: Breakfast @ Self-Prepared
• 08:30: Beach Activities
• 11:00: Prepare to Check-Out 
• 11:30: Check-Out @ RPP Pangkor
• 12:00: Lunch
• Kedai Kopi Lee Meng Yong (李明榮茶室) or
• Island Culture Cafe (潮人馆) or etc...
• 13:00: Shopping @ Pangkor Town
• Laris Duty Free or Sun Duty Free or The Island Shop or Keok Family
• 13:30: Galeri Pangkor (Optional)
• 14:30: Ferry depart from Pangkor Jetty
• 14:45: Reach Marina Island Jetty Complex
• 15:15: Tea break @ Aeon Seri Manjung
• 16:15: Reach home @ Sitiawan
• 17:00: Leaving Sitiawan
• 19:00: Dinner @ Bagan Samak
• 21:00: Reach home @ Penang
• 22:00: Zzz

Post-Trip Notes:

• During online ferry ticket purchased (Marina Island Jetty, Buy Ticket @ RM10/way, Service Charge RM1/ticket), you may add RM2/pax for Reschedule Add-On, with this, you may reschedule your tickets (at least 1 hour in advance). Or, you may try your luck on-the-spot for next earliest ferry (depends on availability and the ticket collector). Boarding the ferry with your QR Code on your phone or printed ticket. Any printed ticket request on-the-spot will be charged RM2/pax.
• Galeri Pangkor was closed during our visit.
• The Pink Taxi we took was excellent with working air-cond (Plate No: BKC8596, Tel: 011-63347335). RM100 for 1st 2 hours, subsequent hours will be charged RM30/hrs. Note: Not every Pink Taxi comes with air-cond.
• Keok Family might have certain items cheaper than other shops, but definitely their Andes is more expensive than Sun Duty Free. So, compare few shops before you decide to buy any chocolates, price varies from shop to shop.
• Laris Duty Free is currently having stock clearance sale until End/Feb 2026. New owner will take over from Mar 2026, will be reopen again after facelift renovation.
• Island Culture Cafe was full house during our visit. Waited for almost 1 hour before we got our seats. Government servants with any valid ID proof eligible for 5% discount.
• Owner of Kedai Kopi Lee Meng Yong was very friendly and polite. We were satisfied with the 1st meal at Pangkor although it has limited foods selection.
• Chicken Rice @ Restoran Chiang Sheng during our visit (CNY holiday) was quite pricey, RM9/plate.
• Due to raining at the evening, we walked to the nearest Coco Restaurant for dinner. We enjoyed the meals @ RM260 for 7pax, with Grouper (1kg), Mantis Prawn, Squid, Toufu, Yau Mak (Vegetable), and Oyster Omelette. 
• Billion Value Mart (Pangkor Town) and CK Supersave Mart (Pasir Bogak) are conveniently located for us to restock some drinks and snacks.
• Upon leaving Pangkor at Pangkor Jetty, Custom Officer will asked you to show your ferry ticket with more than 24 hours stay on the island for tax exemption, if not, you will be charges the taxes accordingly.
• Marina Island Jetty Complex use ANPR system (Automatic Number Plate Recognition), charging RM23 per calendar day. You may opt to pay Parking Fee online (within 15 min before exit parking area).
• Lastly, the RPP Pangkor bungalow that we stayed was awesome. It was newly refurbished and renovated in Dec 2025. Everything looks new and it is so spacious and comfy. Only 1 to 2 min walk to the beach just opposite the main road.

Travel: 2026 | Wolf Supermoon | Super Low Tide | Damai Laut

2026 | Wolf Supermoon | Super Low Tide | Damai Laut

• Location: Damai Laut, Lumut, Perak, Malaysia.
• Date: 04/Jan/2026 (Sun) @ 10:30 ~ 11:00

The Wolf Supermoon on January 3, 2026, creates a specific tidal phenomenon known as a perigean spring tide. This event results in more extreme water levels than usual, significantly impacting low tides.

Lower-Than-Average Low Tides: During this supermoon, the gravitational pull of the Moon and Sun align while the Moon is at its closest point to Earth (perigee). This combined force pulls more water away from the coast during low tide, causing water levels to drop lower than they do during standard full moon phases.

Dragon Spine Formation: The extreme low tide caused by the 2026 Wolf Supermoon exposed long, winding sandbars often referred to as the "Dragon Spine." This phenomenon occurs when a narrow strip of sand or limestone range, becomes visible above the receding sea.

Among the sea creatures found along the Dragon Spine:

• Nine-Armed Sea Star 
• Star Fish
• Mussel
• Oyster
• Asian Clam
• Sea Snail
• Duck Mouth Clam
• Sea urchin
• Crab
• etc...

Related Info:

• Great Place To Go... 无处不去: Sitiawan 实兆远(马来西亚半岛之小福州)
• Great Place To Go... 无处不去: Sitiawan Cookies 实兆远光饼
• Great Place To Go... 无处不去: Local Delicacies @ Sitiawan
• Great Place To Go... 无处不去: Vacation @ Damai Laut 度假去
• Great Place To Go... 无处不去: WCE (E32)
• Travel: Pangkor Island 2D1N @ Govt RPP (Rumah Peranginan Persekutuan)