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Introduction

Repair of the control module (replacement of 4 components).

Symptom: Total failure of dishwasher (no function of LEDs or buttons)

Cause: Voltage converter LNK304GN is defective,

Consequences: protection resistor (100Ohm) also blown. possibly 2 capacitors, 1 varistor defective

Solution: Replacement of all (possibly) damaged components by unsoldering / soldering

Material price: € 3.50

Result: Then fully functional again.

———

Dishwasher name: Bosch SRI45T45EU/18, “Silence Plus” , 45cm width

Name of control module: STM451-EU / 00643257] (€ 106.70)

Name of the board: AKO 704226

My sources for this guide

  1. Symptoms of a faulty control module: No function during the wash cycle (no display, no noise, no reaction to pressing a button or switching it on and off). Repair carried out here: replacement of 5 components on the control module (costs: € 3.50); entire control module can also be bought here for € 100) - see step no. 5 + 6.
    • Symptoms of a faulty control module: No function during the wash cycle (no display, no noise, no reaction to pressing a button or switching it on and off).

    • Repair carried out here: replacement of 5 components on the control module (costs: € 3.50); entire control module can also be bought here for € 100) - see step no. 5 + 6.

    • The control module is located directly under the control panel (see picture)

  2. IMPORTANT ---> Disconnect the dishwasher from power before attempting the rest of the steps! <--- IMPORTANT To be able to remove the front plate and control panel, first loosen all of the screws below. 2x marked in blue: long screws that grip directly into the wooden panel of the cover.
    • IMPORTANT ---> Disconnect the dishwasher from power before attempting the rest of the steps! <--- IMPORTANT

    • To be able to remove the front plate and control panel, first loosen all of the screws below.

    • 2x marked in blue: long screws that grip directly into the wooden panel of the cover.

    • 4x marked in red: short screws that hold a metal frame on which the cover is fixed.

    • 4x marked in green: short screws that hold the cover of the control element.

    • Cabinet panel can be removed as in picture no. 2 (Be careful that the bezel does not fall off when loosening the screws!)

    • Now you can remove the control panel.

  3. The switch module can be removed by carefully loosening several clips - note the markings on the pictures and carefully pry open with a screwdriver. The switch module can be removed by carefully loosening several clips - note the markings on the pictures and carefully pry open with a screwdriver.
    • The switch module can be removed by carefully loosening several clips - note the markings on the pictures and carefully pry open with a screwdriver.

  4. Remove all plugs from the control module, bending the clips slightly to the side (blue markings) Open the cover, bend the clips slightly to the side (red marking) and open in the direction of the arrow (Image 1 + 2) Fig. 3: AKO 704226 board can be removed from the control module (framed), LED + switch module can also be removed for easier soldering (flat cable remains connected).
    • Remove all plugs from the control module, bending the clips slightly to the side (blue markings)

    • Open the cover, bend the clips slightly to the side (red marking) and open in the direction of the arrow (Image 1 + 2)

    • Fig. 3: AKO 704226 board can be removed from the control module (framed), LED + switch module can also be removed for easier soldering (flat cable remains connected).

  5. What needs to be replaced on the control module to fix the error? 1st component LNK304GN = cause of error!
    • What needs to be replaced on the control module to fix the error?

    • 1st component LNK304GN = cause of error!

    • Whether the component is defective can be checked in the installed state with resistance measurement between source and drain: R (S-D), see Picture No. 2

    • Defective, when(S-D) < 100 Ohm

    • Normal when R(S-D) > 10 MOhm (depending on the polarity)

    • Spare part e.g. from here, 1.08$; is referred to as "power integrations LNK304GN-TL PMIC - AC / DC converter, offline switch holder, converter amplifier, flyback SMD-8B

    • Desolder all 7 pins (these are only soldered from the top of the board. However, I carefully cut off the pins with scissors / pinchers, removed the IC and then soldered the pin residues one at a time). Solder new component LNK304GN.

  6. Change other components that may also be defective due to a chain reaction (these are all primary components for converting the mains voltage): Protective resistor: R = 100 Ohm, 3W [2. Circle from above]. Spare part e.g. from here, 0.26$ IMPORTANT: the resistance must be fire-proof / flameproof - check on the data sheet!
    • Change other components that may also be defective due to a chain reaction (these are all primary components for converting the mains voltage):

    • Protective resistor: R = 100 Ohm, 3W [2. Circle from above]. Spare part e.g. from here, 0.26$

    • IMPORTANT: the resistance must be fire-proof / flameproof - check on the data sheet!

    • Reason: the resistor acts as a fuse and should burn in the event of short circuits / defects without flame formation and protect the rest of the circuit.

    • Capacitor C = 10µF, 400V, electrolytic capacitor, [top circle] (note polarity, neg. Electrode with - marked on component and board)

    • Foil capacitor Kemet X2 46K MKP, 0.1 µF, 10%, 10 mm (was not necessary for me) Spare part e.g. from here, 0.86$

    • Disk varistor TDK S10K275, 430 V [bottom circle]; Spare part e.g. from here, 0.53$

    • Image 3: After assembly, the switching module and the dishwasher work perfectly again!

Conclusion

To reassemble your device, follow these instructions in reverse order.

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Robert

Member since: 01/16/2014

689 Reputation

3 Guides authored

20 Comments

Schöne Reparatur - Glückwunsch!

VauWeh - Reply

Danke.

Ich freue mich über Kommentare - vor allem wenn jemand unklare Schritte findet, Verbesserungsvorschläge hat oder einfach Erfolg mit der Reparatur hatte.

Robert -

Vielen Dank für die Anleitung. Hat gut geklappt. Ist hatte leider etwas Problem beim herauslösen von dem Chip.

Hatte leider keine Entlötlitze da, wodurch selbst mit viel pumpen immernoch etwas Lötzinn unter den Füßen war. Habe mir damit ein bisschen die Leiterbahn demoliert. Aber schlussendlich hat alles gepasst.

Bei mir mussten auch nur der Chip und der Widerstand gewechselt werden.

Danke dir!

Christian M. - Reply

VIelen Dank für die Rückmeldung - wieder ein Geschirrspüler vor dem Schrott gerettet - sehr gut! Dann habe ich wohl nichts wesentliches vegessen.

Genau wie du hatte ich (mangels Profiwerkzeug) Probleme die Pins zu entlöten. Deshalb habe ich auch die Pins zuerst vorsichtig durchgeschnitten (kleine Schere/Zange/Kneifer), den IC entfernt und erst danach die Reste der Pins freigelötet. Ich habe die Anleitung an diesem Punkt etwas präzisiert.

VG, Robert

Robert -

Bei mir hat es nach der Anleitung auch bestens geklappt. Danke! Da ich seit >10 Jahren aus dem Elektroniker-Job draußen bin, war es nicht schlecht, ein paar Anhaltspunkte zu haben.

Ich habe bei Conrad außer dem IC und dem Schutzwiderstand noch den ElKo und den Varistor auf Verdacht mitbestellt, der Folienkondensator war in der passenden Kapazität gerade nicht lieferbar, war aber offensichtlich auch nicht defekt. Der ElKo sah aber auch ok aus und am Varistor war optisch auch nichts zu erkennen.

Das Entlöten der SMD Flächen war in der Tat das Schwierigste. Da ich mit dem Seitenschneider nicht richtig zwischen die Beinchen kam, keine passende Schere parat hatte und auf keinen Fall die Lötflächen abreißen wollte, habe ich den Flächen etwas frisches Lötzinn zugegeben, sie erhitzt und dabei mit einem ganz kleinen Schlitzschrauber vorsichtig jedes Beinchen einzeln hoch gebogen und danach mit Entlötlitze das Zinn wieder entfernt. Nur mit der Entlötzlitze war leider nix zu machen.

1178-111 - Reply

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