AMS 39 640 sensit 1 issue

[Bird Vending Services]

Hello Everyone - 

I have an old AMS 39-640 sensit 1 machine that is having problems.  When cash is inserted or a card is used, the credit gets accepted but once you select an item, the selection sits on the led screen for about 5 seconds or so, then the machine says “make another selection” and refunds the money or the card reader shows $0.00 sale and vends nothing.

After going through the owners manual, I replaced the emitter and detector boards (the two sensors in the drop bin).  Now the machine gives me:

pulse - 11; basis - 255; pwm - 532; drop fail; status 38 

before I replaced the two sensors, the basis number was 2 - so I figure one or both of the sensors were bad and needed replacing.  I have a sensor harness and a board in my inventory and tried replacing them both but the problem persists.  It is possible that the board and/or sensor harness were also bad. Any guidance or help would be greatly appreciated as the machine is having the exact same problem it did in the first place. 
 

This machine is located in a diesel repair shop so the guys can get pretty rough with the machine. 

 

 

 

[AZVendor]

Here is the manual:  https://www.dsvendinginc.com/images/vending-machine-manuals/AMS/model-35-39-VCB-VCF-sensit-1-glassfront-service-manual.pdf  It sounds like you have it already due to your parameter listing, but here it is.

Page 38 tells you how to calibrate the sensors and what acceptable readings of those parameters are.  You probably need to run the calibration routine a couple of times.  If your machine is still using Sensit 1 sensors I don't know where you found replacements.  That is the first iteration and those sensors weren't long lasting and are no longer available, I thought.  Look for bright light possibly hitting on the glass and there should be a light diffuser on the receiving sensor.  Sometimes two layers of it.  But if your issues continue the only real fix is to upgrade the machine which is to install a Sensit 2 (unlikely to find) or Sensit 3 logic board and sensors.  It's a pricey upgrade.

[Bird Vending Services]

Thanks for the response AZ.  The basis number was 2 with my old detector sensor board and 255 with my new detector sensor board.  Ams tech support told me that in their opinion both detector boards were bad.  
 

I am going to upgrade to an AMS sensit 2 chilled snack machine for $1850.  Are the sensit 2 parts still widely available?

 

Also - little bit of a tangent.  In my neck of the woods finding resale vending machines used to be easy.  Now they appear to be in scarce supply.  Am I the only one who has noticed this?

[AZVendor]

I haven't worked on an AMS for a while but since the S2 came out quite a few years ago you'd need to look at D&S or Vendors Exchange to see if they still have the sensors.  It's also possible they are the same between the S2 and S3.  The main difference between S2 and S3 was the S3 motors had home switches so they got different logic boards.  Check the two parts manuals and if the sensors are the same you'll be fine.