I have a Jack Lalanne Power Juicer. The top piece

The safety switch is on the bottom base where the pulp collection bin goes. If you look on the pulp collection bin there is a small tab that when assembled right deactivates the safety switch. The main arm that holds the top container where you put the produce in is also a safety mechanism that when not in place the machine will not turn on.

You need to rinse the juicer parts as soon as you finish juicing.
Here's some Juice Recipes For Healing
Here's the manual to help you take it apart-
Jack Lalanne Power Juicer manual

The manual for your Jack LaLanne Power Juicer can be found here:

http://www.powerjuicer.com/power-juicer-manuals.php

The manual contains illustrated assembly and disassembly instuctions

You may also find the How To videos to be helpful:

http://www.powerjuicer.com/power-juicer-how-to-videos.php

Mine stopped working after only a few uses. It turns out that the safety microswitch button wasn't being depressed. The little button on the bottom of the pulp collector had broken off. (Image #1) I put a 1/4 inch piece of a shishkabob skewer in the hole before putting the pulp collector on. (image #2) It works fine now. It's still safe. The motor will not start unless the pulp collector (receptacle) is in place and locked in. Be sure to unplug the machine before doing this.

Took the machine apart piece by piece and figured it out myself

Regarding Jack Lalanne juicer. After making sure nothing clogs the blades., make sure the stainless bar is on the correct slots on top of the juicer, left and right. It has a safety switch that when its not closed properly, it won't run.

The stainless bar should be on the correct slots on top of the juicer. It has a safety switch on those bars. Smell the motor from under the juicer, it should not smell like burnt. Press hard on the switch, it might be loose.

The top white part connects to the motor. You have to buy the whole bottom part. It's not separate.

The pulp collection receptacle has a tiny clear plastic button on the bottom. If this has broken off (it happens often) the machine won't turn on. The button must be present to depress the safety switch at the bottom of the machine. If everything else is properly assembled and the machine won't turn on, this is probably the cause. Check the bottom of the pulp collection receptacle to see if the button has broken off. (picture #2) If so, replace it with a piece of pasta or a tiny piece of wood. Sounds silly, but it works. The safety switch at the bottom of the machine must be depressed before the machine will run.

Hi smer67 - This is what it says on the official site about spare parts: See the back inside cover of the instruction manual for the spare parts order form or call: 1-973-287-5150
(MON-FRI 9AM to 7PM EST & SAT 9AM - 5PM EST). If this answers your question PLEASE rate this as fixed. If you need more help just add a comment and I'll be happy to assist you further. Thanks.

Jeff