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SUPERV6 said:A flat blade screwdriver CAREFULLY inserted down the side of the knob to find the edge of the circlip is one way and push the circlip off. You may need to reinsert the screwdriver from both sides to get the circlip to evenly move off. To reattach the knob...pre load the circlip back onto the knob then line the knob up with the shaft and press the whole assembly back on firmly until the circlip pops back into its groove.
And HERE is another thread about the same problem