Mooman333 Posted December 29, 2011 Share Posted December 29, 2011 Just picked up National Vendors 145 with a MAKA bill validator. When I plugged it in at home, it read coins only and top tray did not work. I took DBV out and hooked it up to my tester and and accepted bills, but did not show a value on tester (should read 1 per dollar). I continued on and fixed the top shelf by bending the electrical contacts out a bit. I put the validator in for the heck of it and it started working correctly and showed correct credit when you put in bill, and gave correct change. Now i have moved the unit on site. Now it won't work. Coin mech tubes are full. Test vend works fine and it takes coins and gives change, but validator is non functional. When machine is powered up, DBV cycles, but won't take in dollars. Says coins only on screen when door is open (not sure if it says that when door is closed, i think screen is just blank). Any ideas where i should start? What does it take to upgrade bill changer? Is it just a matter of a jones plug or adapter harnesses, or do I have to by a upgrade kit with a computer board adapter thing? What exactly is the function of the door switch? I assume a bad switch would cause some problems as well...? Does coin mech have anything to do with DBV function? I have read some other post about this issue, but no concrete answers. Link to comment Share on other sites More sharing options...
Technivend Posted December 29, 2011 Share Posted December 29, 2011 Just picked up National Vendors 145 with a MAKA bill validator. When I plugged it in at home, it read coins only and top tray did not work. I took DBV out and hooked it up to my tester and and accepted bills, but did not show a value on tester (should read 1 per dollar). I continued on and fixed the top shelf by bending the electrical contacts out a bit. I put the validator in for the heck of it and it started working correctly and showed correct credit when you put in bill, and gave correct change.Now i have moved the unit on site. Now it won't work. Coin mech tubes are full. Test vend works fine and it takes coins and gives change, but validator is non functional. When machine is powered up, DBV cycles, but won't take in dollars. Says coins only on screen when door is open (not sure if it says that when door is closed, i think screen is just blank). Any ideas where i should start? What does it take to upgrade bill changer? Is it just a matter of a jones plug or adapter harnesses, or do I have to by a upgrade kit with a computer board adapter thing? What exactly is the function of the door switch? I assume a bad switch would cause some problems as well...? Does coin mech have anything to do with DBV function? I have read some other post about this issue, but no concrete answers. The 145/146 will always read "coins only" with the door open. It is due to the door switch that you reference. This switch puts it into vend mode or service mode. The coin mech does have a lot to due with the acceptance of your bills in this style machine but the function of accepting a bill does not. What I mean by this is if the machine tries to take in a bill and then spits it back it is probably the validator. If the validator does not try to accept at all it is probably the machine/mech. I would start with the coin mech if you have one. It is the cheapest and best way to start. If it still doesn't work and you are sure the validator does work outside of the machine I would say it is probably the coin mech interface board. As far as upgrading the validator, you can and I believe the Mars is the easiest upgrade. Personally I wouldn't put the money into a validator upgrade, the Maka is a perfect match for the 145. Link to comment Share on other sites More sharing options...
Mooman333 Posted December 30, 2011 Author Share Posted December 30, 2011 Thanks for the quick response Bill. I replaced the MC5000 coin mech with a TC6000 and the bill validator started functioning properly. Easy fix! What does the coin mech have to do with the function of the DBV? I kind of thought they were separate entities since both hook to board in snack machine. Can the MC5000 that i took out of the machine be fixed? It seems to function just fine on my mech tester, I would have labeled it as a good mech and sold it if i wouldn't have know it had the issues with the DBV in the snack machine. Link to comment Share on other sites More sharing options...
AngryChris Posted December 30, 2011 Share Posted December 30, 2011 I can't really give the exacts on which machines have which kind of mechs (ie. dummy mechs) as I am not greatly familiar with older technology so much but I can tell you this: If a coin mech is not working properly or if the vending machine THINKS that the coin mech is not working properly, the machine will NOT accept dollar bills... Why? Because if the coin-mech cannot give change, the machine will not allow itself to accept dollars (due to not being able to give change). I know it sounds silly that the machine will take and give all coins but not accept dollars due to the coin mech not working but that's generally the case; a malfunctioning coin mech will cause the machine's board to disable the DBV. As to what the problem is... it could be a poor connection with the coin mech plug (such as mine seemed to be having) or it could be various other things... believe me, it's hard to make sense out of the way some older model machines react when faced with a slightly-malfunctioning coin-mech but all the machines know is "Hey, the coin mech isn't working right so lets disable the DBV" which promptly results in "Coins Only" Now if you were prompted with "exact change only" then that would be a different problem which could be caused by countless other reasons!!! There's so much more info that I could give you but it would only continue to confuse you Link to comment Share on other sites More sharing options...
Technivend Posted December 30, 2011 Share Posted December 30, 2011 The older electronics machines and their dummy mechs relied heavily on complete communication with the machine to function properly. The validator did as well, as the MAKA and other pulse validators of the day only had a switch closure to send an accept signal that was generated from the machine back to the machine. It was kinda like this... using a quarter vend price to simplify. Insert coin, mech says to the machine "someone dropped in a quarter, can I use it?" Machine to mech "yes we have something priced in the machine that we could use the quarter for". mech to machine "what should I do with it?" Machine to mech "your sensors tell me you need more quarters in your tubes so put it in your change tube" Mech to machine "ok quarter is in my coin tube" Mech to machine "I just got another quarter now what?" machine to mech "we don't need it because our maximum price is already met so don't accept it" Now if we add a bill to this it changes somewhat. There is a signal sent to the validator that is waiting for a relay type closure to send the signal back to the board to signify a bill has been accepted. So in order to not steal bills the machine will inhibit the acceptance on the validator. You will get the 110v power which will cycle your validator and put it in standby but the board will tell the validator NOT to accept through and inhibit circuit. Val to machine "someone is putting in a bill what do I do" machine to mech "I need to pay out change can we do it" mech to machine "nope" Machine "I have no change or cannot give out change so I better not accept this bill" and sends out the inhibit signal not allowing the validator to start the cycle. This is an over simplification of the actual logic but it should give you a better understanding. The board controls everything in the 145/146 machine. This is why the mechs were referred as "dumb". Link to comment Share on other sites More sharing options...
AngryChris Posted December 31, 2011 Share Posted December 31, 2011 So if I have this right, on a dummy mech, the board does ALL of the thinking for the coin-mech and the validator while the mech and DBV only do the "validating" of the currency. On the other hand, from what I understand, a modern mech will have more control over the DBV and deciding what to do with the currency but the board still has the final say... I guess a prime example would be... if a bad coin is inserted into a coin mech, on a dummy mech, the board has to send a signal to the mech to reject the coin... where on a modern mech (such as most MDB mechs), the mech can reject it without having to ask the board... See, I said it would further confuse people . But really, a faulty mech = faulty DBV functions. Link to comment Share on other sites More sharing options...
Technivend Posted December 31, 2011 Share Posted December 31, 2011 The coin mech will decide if it is a good coin or not. Think of it in terms of a coin acceptor. The key is that it can only do what it is told. A newer mech can keep account of the amount of coins, use adjustable tube levels, know exactly if the coin tubes can payout change to the nickel. However in some applications the main pcb will try to override the mech. Link to comment Share on other sites More sharing options...
AngryChris Posted January 1, 2012 Share Posted January 1, 2012 I should have stayed in vending college. Link to comment Share on other sites More sharing options...
Poplady1 Posted January 1, 2012 Share Posted January 1, 2012 The coin mech will decide if it is a good coin or not. Think of it in terms of a coin acceptor. The key is that it can only do what it is told. A newer mech can keep account of the amount of coins, use adjustable tube levels, know exactly if the coin tubes can payout change to the nickel. However in some applications the main pcb will try to override the mech. Bill thanks so much for taking to time to write all of that down. Link to comment Share on other sites More sharing options...
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