Dishwasher Motherboard Repair

Profilo Dishwasher Won’t Turn On Problem and Motherboard Repair: In this article, I’m sharing in detail the motherboard repair I performed for my Profilo BM3120EA dishwasher that wouldn’t turn on or had no lights on. If your Profilo, Bosch, or Siemens dishwasher isn’t turning on, isn’t getting power, or has no lights on the front panel, the problem is most likely due to the power supply circuit on the motherboard.

As I mentioned in the article “Standby Mode Power Consumption, Electricity Saving and Protecting Electrical Appliances” the continuously active power supply section on the dishwasher’s main circuit board has malfunctioned.

Dishwasher Mainboard Measurements and Replacements

After checking the power outlet and cables, I removed the mainboard. The board is located in the lower right corner of the machine; you can access it by removing the right door of the dishwasher. The TNY264GN SMPS integrated circuit had blown, and a 3W resistor had also burned out. Its value appeared to be 100-Ohm, but I checked the image to see if the color change would be due to the burnt-out resistor, and the 100-Ohm value was correct.

Replacements:

TNY264GN integrated circuit
100-Ohm 2w resistor
220nF 305V capacitor
470uF 16V capacitor

Dishwasher Circuit Board Repair: Components to be Checked

The capacitor (the blue one on the left) connected in series with the 100-ohm resistor showed no visible problems such as cracking or swelling, but since it’s connected to the resistor, I measured its value and it had dropped. It should normally be 220nF, but three different multimeter measurements showed values ​​around 143nF.

To repair the dishwasher circuit board, I first measured the diodes I’ve marked in the image below. Finding no problems, I replaced the TNY264GN, 220nF, 100-Ohm and 470uF 16V capacitors. The dishwasher then worked perfectly.

Circuit diagram of the auxiliary power supply with TNY264GN integrated circuit on a dishwasher motherboard.

Caution: The auxiliary power supply made with the TNY264GN SMPS integrated circuit is not isolated from the mains; exercise caution when taking measurements.

Suggestion for Safe Testing

I measured the diodes shown in the pictures, and they were all working. Afterwards, I removed the faulty parts and replaced them with new ones. I tested the motherboard by connecting it to a dishwasher. It’s essential to take all necessary safety and protection precautions and test the board before connecting it to the machine. However, resources and space are limited.

For dishwasher board repair, use the lamp protection method (Lamp Protection for SMPS Testing) I mentioned earlier when testing the motherboard. First, connect a 220V 100W lamp in series with the 220V input and apply power. If there are no problems, remove the lamp.

Connect to pins 3 and 4 of the large white socket. Pins 3 and 4 are the resistor connection points. Make a standard 220V connection without a series lamp. Then measure the input and output of the 7805 regulator IC; it should be around 13V at the input and 5V at the output.

Dishwasher Brands and Models Using the Same Main Board

Which dishwashers use the same main board? The main board found in the Profilo BM3120EA dishwasher is also used in Bosch and Siemens dishwashers. Although offered with different software and features, the power supply part is completely the same. Therefore, the solution to the “Profilo, Bosch, and Siemens dishwasher won’t turn on” problem is often main board repair.

Some of the models I’ve identified are:

SMD codes on the dishwasher circuit board:

PR(SR) TVS Diode SMAJ170A-SMBJ170A DO214AC
L9 Zener Diode BZX384-B12 SOD323
F5 Diode FRS1J DO214AC
B3 Diode MBR0530 SOD123
A7w Diode BAV99 SOT23
A4 Diode BAV70 SOT23
A6 Diode BAS316 SOD323
A1w Diode BAW56 SOT23
S2M Diode DO214M
UD Diode UES1, US1D DO214AC
XDs Transistor BC555 SOT23
1Gt Transistor BC847C, SOT23
6Ct Transistor BC817-40 SOT23
W(P or T)18 Transistor PDTC143ZT
D13003 Transistor STD13003 DPAK
221 Opamp TSH22, SO8
Z0109 Triac Z0109MN SOT223