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     Hello all. Newbie here, after reading and searching I finally came tho the conclusion that I need help :darn:.  I made my own free vend momentary switch (Thank you jonnieG) for my Vendo VF128.  After installing the switch I push the momentary switch and you hear a click, I then try to make a selection and nothing happens. There's 5 cans in each of the selection and the "out of product" switches are all held down by a can. While looking in the relay box when I push the button, only the square relay activates, the other one "Sequence Relay Assembly?" does nothing. The serpentine system seems to work smoothly when I manually vend a can from the vend mech..

first, did it work with the coinmech in place?  If the answer is "Yes" then you should make sure that you've included the jumper from pins 1 to 7 as well as the push button from 1 to 3.

If the answer is "no" ( it didn't work with a coinmech in place, or you never tested it with a coinmech because it didn't have one or the coinmech never worked to begin with) then next you should check for loose connectors on the underside of the rack ( feeding all of those nice little micro switches)

to get to the bottom of the rack easily, unload the cans, (or jam them in place with a bunch of rags so they don't roll backwards & get pierced & spray soda all over) remove the two large bolts at the top left & right of the rack, (don't lose the spacers that go along with them.) loosen the wire-harness retaining clamp (if there is one)  pull the top of the rack forward & tip it out of the machine, the bottom is pivoted, but you'll need a box or a plastic milk-crate to support it, now look at the bottom & carefully inspect the switches for loose or broken connectors, this style of rack is notorious for cheap/brittle brass connectors.

WOW, thanks for the quick response.  The coin mech. did not work when I got the machine.  So I just unpluged the Jones plug and made your momentary switch from pins 1 & 7, and pin 3, just like the diagram. I read some of your other post about cleaning out the bottom after tilting out.  I unpluged and removed each vend, cleaned and reassembled. Nothing was broken or dirty (sticky).

I can see the rack has "paddle-wheel" style vending gates be sure to double check the vending "pre-load" switches as well as the "empty" switches.. if the rack is "ready to vend" you should see 120 volts on pin #7 to chassis ground. before you hit the free-vend button. if not, you have an open circuit  somewhere.

Where might I find these "pre load switches"? I'll also look at what voltage pin #7 puts out prior to pushing the free vend button.  What does that other relay do that's in the same box?

Voltage to pin #7 prior to pushing free vend = 32 volts. Still looking for the pre-load switches.

sorry, about time to make dinner for me & my boy, but the one should be the credit relay, I'd have to see the schematic to determine the other.   if you push the top of the credit relay, it should self-latch, at which point you should be able to select a drink button, the other relay may be a time-delay to terminate the vending credit either after the selection has been delivered, or after a specific "time-out" has been reached in which case it may unlatch the credit relay.

I just thought of something else too, some of these earlier vending machines had a delivery switch somewhere about the bottle (can) chute exit, typically attached to the bottle door ( can door in your case) if it's not set correctly, (IE: the door is closed) it may interfere with a vending cycle too.

32 volts is too low, unless it's stuck in the middle of a vending cycle. the switches are typically located on the bottom/underside of the delivery tracks it detects a minimum number of cans in each column ( usually two or three minimum) about two -cans up the serpentine rack, the cans sit on it & tell the coinmech that there is enough product to vend, ALL of the columns must have at least 2-3 cans each in this type of machine.

Thanks again johnnyg.  I just looked at the can door and didn't see any switch or wire at all.  I did unplug the machine and pluged it back in, checked the pin voltage again and found that pin 1 and pin 3 had 117 volts, pin 7 had nothing.  Sorry I'm not a very good electrician but what did you mean by a chassis ground?  Again there are 5 cans in each rack and it appears that all the switches have cans on them.

chassis ground = one test lead to the metal of the machines body/frame, the other to the point being tested.

Chassis ground, now understood.  Well I must have a open circuit like you said. Pin #7 = 0 voltage. Where might be a good starting point? 

Found a bad micro switch that operates the "out of product" switch. At first I thought I just had a burnt out bulb, tested the bulb in a different plug and it worked. Did a continuity test on wire all the way to the micro switch, pulled the micro switch and found it broken. I did find some micro switches and ordered them. Thanks again johnnieg. :laugh:

naa naa I told you so...glad you fixed it!  :tounge: