Trouble shooting s75-9800b

[USMC Vet]

When I put nickels in to get a soda (got it set for 10 cents) the first nickel falls into the the correct place,the nickel stack, but the second nickel falls into the dime stack,is this correct? Also when I put a dime in it falls into the coin box that you get your money out of,and the dime stack is not full.Thanks!

[BryanH]

Are you sure that you don't have two nickel stacks?  Some mechs could only keep nickels as change inventory.  Everything else dimes and quarters went into the coin box.

[USMC Vet]

Did not know that.Is there anyway to tell?Thanks!

[johnieG]

Quote (BryanH @ Nov. 28 2005,5:50)

Are you sure that you don't have two nickel stacks?  Some mechs could only keep nickels as change inventory.  Everything else dimes and quarters went into the coin box.

Yep, you're right, A Coinco S75-9800 series A/B only has (two) nickel tubes, & dimes and quarters do go straight into the cash-box. There is a 9300 series by Coinco that does have one nickel & one dime tube & looks very much like a 9800 series 'mech. Ive repaired some a while back for moondawg I believe...

[USMC Vet]

Learn something new everyday,especially here.Thanks so much,thought my coin mech was messed up.

[bubba]

I have the "A" model of this coin changer. It is currently set to .50. What can it be set for? I haven't really looked at it yet - its just too darn cold to be out there right now.

[Skeleton Man]

Quote (bubba @ Dec. 14 2005,12:28)

I have the "A" model of this coin changer. It is currently set to .50. What can it be set for? I haven't really looked at it yet - its just too darn cold to be out there right now.

You can set it anywhere between 5¢ and 75¢ in 5¢ increments. It has 4 slide switches which are used in combination (e.g 5¢ switch up + 20¢ switch up = 25¢)

Coinco Manual

[bubba]

Excellent! Thanks... I appreciate it.

[Skeleton Man]

Happy to help !

[bubba]

Well, I fired up my vendo 63, and the changer is not working.. I started probing around with my meter a bit.. What is the voltage out of the transformer? I'm not getting anything on the output of the transformer, according to the pinout on the diagram. There are some burn marks on the back of the logic board, and one of the caps on the other side of the board is getting hot by the trace. I don't know if the board has been repaired previously, buy my guess is that it has. I'm not quite sure where to start with this. It looks pretty basic and I can probably figure it out. I don't want to start dissasembling the back cover until I know whats in there... does anyone have a manual or any info on the S75-9800A changer?

The panel lights up, the compressor works, and this thing is like an ice cube machine. The door light is out, but the bulb looks black, so I'm sure its shot. I did trip the GCI outlet in my basement, but I thought this machine only is supposed to draw ~6amps....

[Creighton]

Ken,
~6amps pull is around what I see with a RT-V56. JohnieG will know what to do for fixing the Coinco.
Creighton

[johnieG]

Quote (bubba @ Dec. 23 2005,9:08)

Well, I fired up my vendo 63, and the changer is not working.. I started probing around with my meter a bit.. What is the voltage out of the transformer? I'm not getting anything on the output of the transformer, according to the pinout on the diagram. There are some burn marks on the back of the logic board, and one of the caps on the other side of the board is getting hot by the trace. I don't know if the board has been repaired previously, buy my guess is that it has. I'm not quite sure where to start with this. It looks pretty basic and I can probably figure it out. I don't want to start dissasembling the back cover until I know whats in there... does anyone have a manual or any info on the S75-9800A changer? The panel lights up, the compressor works, and this thing is like an ice cube machine. The door light is out, but the bulb looks black, so I'm sure its shot. I did trip the GCI outlet in my basement, but I thought this machine only is supposed to draw ~6amps....

If the mech is dead (no functions whatsoever) & the transformer is open ( it should have 12volts AC on the output side) & the traces (etched copper traces) are burnt & lifted off the board, then sad to say, it's time for a new 'mech.

I can walk you through the failure & you can see if you can replace the damaged components, but chances are it's "toast" so, you can find a "doner" coinmech with a damaged plastic body to swap out the transformer & logic board into your "guts" or you can just buy another one to replace it...

1). As the mech ages the main filter capacitor starts to dry out,this causes excessive A.C ripple on the D.C. side of the logic circut. this cause the coin logic chip to malfunction, miscounting accepted coins & usually causing a "over the top" vending price ( it ignores the vending/price switches), or it ignores a properly accepted coin signal from the coin switches, (typically the quarter circut seems to go first)
2). this ripple voltage also starts to cause errors in coin acceptance ( wrong change given back, won't count the correct amount for coins accepted, & the change motor starts to "ghost" giving back nickels even when the correct amount of coins has been inserted/accepted by the mech).
3). the dryed out capacitor starts to draw too much current form the Zener diode, which in turn starts to "toast" the big load restistor on the PCB next to the capacitor
4). this causes futher damage to the capacitor, which eventually fails, but not before shorting out & overheating  the copper traces, causing them to lift off of the board...
5). By now the zener diode/voltage regulator has had enough & also fries, which causes too much current to be drawm from the transformer & "pops" the built in over temp/current protector ( a one-time safety fuse built into the windings of the transformer) & the mech dies...

sad isn't it?  '>

[bubba]

Wow... it is very sad.... It doesn't sound like its worth trying to repair the board then.. I have one trace that has copper showing for about an inch, but has continuity across both sides. I couldn't see how to get the logic board off the plastic. I also could not find the spot where the dip switches are to select the money..

Well, do you or anyone have a changer they'd like to part with? I've seen a few on ebay, but figured I start in house first...

[Skeleton Man]

That's probably what happened to my 9800A changer.. I'll check the transformer coz the AC side works (crems click), but no DC (no coins accepted, inventory motors don't run)

[bubba]

Here are some pics of my logic board. It looks to me like changing that one cap should do the trick. I don't see anything else that looks blown. There is no transformer on this board that I can recognize... where is it?







There are larger images of both pics here:

http://www.ardgroup.com/ken/top-board.jpg

http://www.ardgroup.com/ken/bottom-board.jpg

[Skeleton Man]

Correct me if I'm wrong.. but it looks like the diode is burnt out.. mine was exactly the same, but replacing the diode didn't help at all..  also that copper part is a fuse.. (if it blows you can solder a strip of wire across there)

I gave up on mine and bought a new changer..

[bubba]

I don't think thats a diode, is it? I thought it was a capacitor, but I can't make out any #'s on it. The leads coming out of it are a bigger diameter than most electronics parts I've replaced, so I'm not sure what the heck it is. I just got a new changer, and the machine is working,but I love to tinker with stuff, so I'm gonna give it a shot to repair it. Its broken anyway, so I can't make it much worse. I get continuity across the copper trace, so IMHO its still a good circuit. Atleast now I have a working unit to compare with.

[johnieG]

Quote (bubba @ Dec. 30 2005,6:18)

I don't think thats a diode, is it? I thought it was a capacitor, but I can't make out any #'s on it. The leads coming out of it are a bigger diameter than most electronics parts I've replaced, so I'm not sure what the heck it is. I just got a new changer, and the machine is working,but I love to tinker with stuff, so I'm gonna give it a shot to repair it. Its broken anyway, so I can't make it much worse. I get continuity across the copper trace, so IMHO its still a good circuit. Atleast now I have a working unit to compare with.

it's a 12volt, 1/2 watt Zener diode (voltage regulator) not a capacitor, if it's too far gone, ( kinda looks like yours is past its prime) then it takes out the CPU with itself, the the board is "toast". you can try to replace it, but don't be surprised if the whole board goes "snap" "crackle" "pop" when you fire it back up!  

[bubba]

Thanks, Johnnie.. What the heck.. I'm gonna pick one up next time I do a parts order and see what happens. I'm pretty good at letting smoke out of electronics, so this should be right up my alley

[johnieG]

Just make sure the replacement is installed correctly with the polarity strip (if you can still see it) pointing in the same direction as the original, cut one end of the old ones wire, & gently look underneath, that side hopfully should still be visable, you're looking for a white/silver strip of paint that marks the negative end of the Zener diode, here's a basic diagram showing the transformers location on the Coinco 9800 series coinmech chassis...

[johnieG]

Here's the component layout/ID...enjoy!  
 :'>

[bubba]

Excellent info.. Thanks for the time to label everything JohnieG.. I do appreciate it. To get to the transformers, I need to pull that other cover off the back of the changer. There are a bunch of screws holding the cover on.. I didn't know if they were holding anything else or just the cover. Guess I'll find out soon enough.

[Skeleton Man]

Let us know if you get it working :-)

[Skeleton Man]

Is the failed zener a common problem on these changers ? Mine had scorch marks just like bubba's, again with no other physical damage evident..

Do the CREMs run off AC line voltage or regulated 12V ? What about the payout motor (inventory switch) ? (I'm guessing CREM is AC and payout is DC?)

[johnieG]

Quote (Skeleton Man @ Jan. 01 2006,1:14)

Is the failed zener a common problem on these changers ? Mine had scorch marks just like bubba's, again with no other physical damage evident.. Do the CREMs run off AC line voltage or regulated 12V ? What about the payout motor (inventory switch) ? (I'm guessing CREM is AC and payout is DC?)

Depends on the make & model of your coinmech, check your electrical schematic on the machine, typically, most CREMS are line voltage, BUT, that depends on the machine, ie;a 24volt coinmech will fry it's CREMS on a 115 volt machine application, the payout motors can be either AC/line, AC/low voltage, or DC/low-voltage, again it depends on, some of the very early motors were AC/line voltage, this is why I'm cautious & don't like to generalize, besides, "ifin ya' kill 'em, he won't learn nothin' (the riddler/batman)  

As for the the Zener, it's as I descibed it, it's part of a chain of failure events, if you exceed the circuts design, it will lead to component failures, most often, it is the victim. not the cause, but once damaged, it'll damage a lot of components & you end up with a "ghost" in the machines coinmech.

Once you replace any component, you have to benchtest & "burn-in" the 'mech before you put it back into the machine, the coinmech can , and will damage the door-wiring harness, not only is it a pain in the butt, (damage someones V-81 RC Cola & see what happens!) but it's a fire hazard too, sometimes it doesn't pay to "patch"

[Skeleton Man]

I should've mentioned that I'm using an S75-9800A mech.. I think it was you that helped me through replacing the zener.. and I know what you mean about damage.. mine came 'welded' to the wiring harness.. (well pin1 was welded anyway)..  I do have a new mech, I just figured it would good to have the old one as a spare..

[bubba]

Well, the more I'm hearing, the more it sounds like I'm not gonna play with it. I've got a working board changer now, and I don't need to fix this one, just wanted to play. I'm gonna shelve the changer, and prolly toss the board.. It's not worth causing more damage to my now working machine to save a few bux. I learned alot from this discussion though... thanks!