Simpson SWT954

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Simpson SWT954
Preliminary Information
Release Year 2010
Leak Risk Low
Batteries None
Mounting Technology Through Hole, SMD
Capacitor Types Aluminum Electrolytic, Ceramic, Film
Destructive Entry No

The Simpson SWT954 is a 9.5 kg top load washing machine (Electrolux design rebranded as Simpson with minor changes).

Known Issues

Unit turns off after being powered on for a couple minutes


  • Off-line SMPS IC has partially failed and is tripping it's internal over-temperature cut-off


  • Replace SMPS U9 TNY278PN

Unit will shake excessively during cycle and stop with error code 'E17' and four beeps

Causes & solutions

  • Unit is overloaded: ensure weight of load is less than your model's limit
  • Load is imbalanced: redistribute load to be more balanced
  • Bowl springs have failed or become loose: replace or re-tighten
  • Out of balance detection switch is not aligned correctly: replace or re-align

Disassembly Notes

warning WARNING This device contains a non-isolated mains voltage buck switch mode power supply. Low voltage circuity still poses a shock hazard.
  • This device is designed well with service and repair in mind
  • The manufacturer has published exploded assembly diagrams showing all fasteners and components (See 'EX. VIEW DRAWING 7696' for SWT954)
  • The front control panel bezel is held on with two screws at the back of the unit
  • The power supply and motor drive PCB is removed with two screws and unclipped from the plastic holder

Original Parts

Power supply and motor drive PCB


warning WARNING Capacitor C22 is 400 V 470 µF (37.6 J), it does not have a bleed resistor.

RefDes Qty Part Number Brand Series Mount Footprint Failure Mode
U8 1 TNY278PN Power Integrations TinySwitch-III THT 8-PDIP-C Silicon damage causes IC to overheat and go into thermal shutdown

Replacement Parts

Power supply and motor drive PCB

RefDes Qty Compatible Part Number Order Links
U8 1 TNY278PN DigiKey Mouser

If parts are not available or different selection is preferred, you can use the values in the Original Parts section to perform a parametric search

Related Links