DIY Series 42: Pensonic Slow Cooker (PSC-301) Malfunction

Symptoms:

• All status LEDs (Low, Auto, High) are working fine when Power ON, but slow cooker is not heating up.

Findings:

• Found that the thermistor is having open circuit.
• This thermistor should be NC (Normally Closed) by default.

Photos:

1. Turn the slow cooker upside down to start to dismantle the external housing
2. Unscrew the center nut (1st nut)
3. Unscrew the 2 screws of power cord
4. Remove the power cord cover so that the power cord is easily pull out (when needed)
5. Remove the knob cover
6. Remove the nut under the knob cover using plier
7. Push the knob into the housing
8. Remove the inner metal base pot from the external housing
9. Unscrew 2nd nut from the screw to take out the Earth Line
10. Unscrew 3rd nut to remove the thermistor (use plier) and check using multimeter, replace with new thermistor (for this case)
11. Thermistor: KSD301, 250V, 10A, 150°C. (Original part was 145°C)
12. Info on NC (Normally Closed) and NO (Normally Open)

Tools required:

• Screwdriver, multimeter, plier

Costs involved:

Thermistor (KSD-301, 250V, 10A, 150 Degree Celsius, NC): 

• Online Store: US$1 ~ US$2
• Physical Store: US$2 ~ US$3

DIY Series 41: Repair Blown LED Light Bulb (E14 Type, 16W)

Symptoms:

• LED Light Bulb is not working when Power ON, suspect some parts were burnt

Findings: 

• Found burnt mark at 3.9kOhm resistor (Marking: 392)
• Use multimeter to check the resistance on each resistor
• 2 out of 3 resistors were blown, need replacement parts 

Photos:

1. E14 Type LED Light Bulb (16W)
2. Location where the 3.9kOhm resistors were blown
3. Bought a light bulb socket (E27 Type) and converter (E27 to E14) for easy testing
4. E14 Type LED Light Bulb is working now after fixing

Tools required:

• Soldering iron, multimeter, tweezer

Costs involved:

• SMD Resistor (3.9kOhm, 2pcs): US$0.02

DIY Series 40: DIY Repair Rubine IA991D DC Pump Instant Water Heater (No Hot Water, Red LED is OFF)

Symptoms:

• Heater LED is not ON. No hot water.

Findings: 

• Flow Sensor: Magnet misaligned, reed switch is not ON/OFF accordingly
• Thermistor: Thermistor at the top of tank need to be reset (NC: Normally Closed).

[Note: Turn OFF the power supply before any installation / checking / debugging] 

Videos:

1. Test the flow sensor using multimeter (flip it over to let the magnet touch the reed switch). Multimeter shows short circuit (with beep sound) means flow sensor is working fine.
2. Test the Heater is working or not by install it back with power and water supply. Red LED will be turned ON and hot water will flow out if flow sensor & thermistor is in good condition.

Photos:

1. Rubine IA991D DC Pump Instant Water Heater (with internal block diagram)
2. Dismantle of power supply wires (E/L/N)
3. Unscrew 4 pcs of screws to take it down from the wall
4. Checking on flow sensor (reed switch and magnet) functionality, remove the reed switch cover
5. Checking on the thermistor functionality, press the button on top (to reset) if it is not shorted
6. Power ON (without water supply) and test the flow sensor (refer 1st video above)
7. Power ON (with water supply) and test the heater function (refer 2nd video above)

Tools required:

• Screwdriver, multimeter, test pen

 

Costs involved:

• NIL (New Flow Sensor costs about US$15)
• NIL (New Thermistor costs about US$1 ~ US$2)

Action Taken:

• Dismantle the flow sensor, take out the magnet and clean it, then realign it back to work with reed switch correctly.
• Reset the thermistor if it is not shorted by default (NC: Normally Closed).
• Thermistor might need to be replaced if it is frequently disconnected in near future.

DIY Series 39: Repair Phison Infrared Cooker (PIC-2280)

Symptoms:

• Left Side: Auto cut-off after 3 min Power ON
• Right Side: No heat after Power ON

Findings: 

• Left Side: Incorrect wiring connection by previous repairer
• Right Side: Temperature Sensor (heat sensor) malfunction

Photos:

1. Example of Infrared Cooker
2. Dismantle the unit from the bottom side, unscrew 16 pcs of screws.
3. Left Side: Incorrect wiring by repairer, shorted the OUT2 wiring directly to "N" (Neutral) terminal.
4. Left Side: Fixed the wiring back to original location, use hot glue gun to seal the connection.
5. Right Side: Temperature sensor detected having open circuit, suspect wiring disconnected at the tip. 
6. Right Side: Source new part from online store, and replace it.
7. Right Side: Dismantle the heating element and turn to the back, connect the new part with 2 screws.
8. Right Side: Connect the other end of temperature sensor to the control board.
9. The Infrared Cooker after fixing done (before close back the casing).

Video:

1. Infrared Cooker operation back to normal

Tools required:

• Screwdriver, multimeter, hot glue gun

Costs involved:

• Temperature sensor: US$1 ~ US$2