I tried the above, but it did not work for me. I looked around and found a German Forum discussing the same problem and used Google Translate. A very bright guy there point to a large capacitor that had gone faulty - this is 0.22uF at 275 volts rating. I took this out and changed it - got the exact replacement on size and rating at Maplin for £1.29 inclu. VAT. I have a soldering iron so replaced it - please get someone who is used to doing such things on mains equipment because of the serious safety issues. The toaster then worked perfectly. Hope this proves useful to others. I guess Siemens had a bad run of this component.
Laurie in Caversham
July 2011
I know, you probably would not believe it, but I have found this suggestion on the internet and it worked for me. There is a sensitive sensor inside and it prevents the toaster from locking when the are crumbs on the locking mechanism as well as on the heating elements.
HOW TO FIX: remove the crumbs tray, turn the toaster upside down and give it a good but gentle shake for a minute or as long as crumbs keep coming out of it. Move the lever up and down while shaking. Worked for me.
Taras
January 2009
Automatic Answer
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howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix toasters.