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On The Spot Precision Engineering.
After I get off the phone with the service technician I start to look around inside the machine for the mysterious missing proximity switch. I found it deep behind the hand wheel, which is used for manually jogging the sleeve material into position prior to startup. You can see the hand wheel in the picture on the right in page 2 of this section. To be able to work in this very tight and cramped area I used a pulley puller to remove the hand wheel so I could get at the components. After I took off the hand wheel I could see I would also have to remove the timing belt drive pulley, which moves the guillotine cut off knife in and out.
Now I could at long last see what I was dealing with. The minature switch was not really a proximity switch at all. It was a magnetic reed switch. This makes more sense to me. This is an old machine and back when it was made they did not have Hall Effect sensors yet. Reed switches were faster than proximty switches back then because they had a higher hysteresis curve than proximity switches. The problem with reed switches is that sometimes the contacts bounce as they get old giving you false double trips on a single event. I could see clearly that magnet was mounted on a bracket locked in position with a set screw. Loosen the set screw on the holder and the magnet can be positioned to activate the switch when the knife is retracted or home position.