Connecting a Comparable Coin Mech to Ipac2 via 12v and a Zener Diode

[Perihelion]

Hi guys,
i bought a comparable coin mech for my mame cabinet and since im no electrician im quite puzzled how to wire it correctly.

https://www.arcadeshop.de/M%C3%BCnztechnik-M%C3%BCnzkomparator_512.html?osCsid=aort6d28h96hj216p364dmto35
this is the coin comparator, im sure some folks here have already seen this type before


this is how the retailer means to have it wired to ipac via the zener diode to prevent the ipac of receiving 12v


i thought itīd be neat if i could hook the comparator to my aux fan on my pcīs motherboard to deliver the 12v

to make things easier i have prepared a plan for you to paint in. It may just be more fun aswell.
and when its complete it could turn out handy for everyone else to look up .-)

[Ginsonic]

Hi,

1. do NOT use the aux fan output, take the 12V directly from the power supply ( from e.g. a harddisk connector) !

2. notice the direction of the zener diode (the black ring on it directs to pin 2/coin signal) !

[PL1]

i thought itīd be neat if i could hook the comparator to my aux fan on my pcīs motherboard to deliver the 12v

Interesting thought, but how much current can your MB aux fan connector supply?

Some electronic mechs can draw several amps.

How much does yours draw?

If you don't know the answers to those two questions, it's a far better idea to use a Molex/SATA power cable for powering your mech like Ginsonic suggested.

this is how the retailer means to have it wired to ipac via the zener diode to prevent the ipac of receiving 12v

Connect the following to the 4-pin connector in this pic.

5v Zener diode:  Acts as a voltage regulator, dropping the 12v output pulse from the mech down to 5v for the IPac.
*** Must be installed or the 12v output pulse will damage the IPac.  ***
- Band end (-) to pin 2 (top lead in pic)
- Other end (+) to pin 3


Molex/SATA power wires:
- 12v (yellow) to pin 1
- Ground (black) to pin 3

IPac wires:
- Coin input to pin 2
- Ground to pin 3


Scott

[Perihelion]

hey thx for helping out!

i already hooked the coin mech to the aux fan:
12v red cable to mechs 12v input
groundī black cable to mechīs black ground

the mechanism worked fine,
rejecting bad coins, taking my 20 euro cts everytime

then i tried to fit the diode between aux ground and coin ground, which might have been a bad idea...
on startup i heard two zaps, but everything kept running fine,
coin mech rejected the 20cts every now and then and i took the diode out.
hopefully i didnt break it somehow

im looking into your solution now !
what puzzles me is the ground lines and where along the coin mechs gound cable to connect the  other grounds/diode.
it doesnt come natural to me as i dont know a lot about current flow.-)

[Titchgamer]

Just push the 2 ends of the diode into the terminals of the mech.

Sounds like the damage may already be done though

[Ginsonic]

A zap means damage I fear !
Maybe only the diode died, but disconnect the coin signal line immediately from your Ipac ! If 12V flows into the port, the Ipac will be damaged severely either !

i already hooked the coin mech to the aux fan:
12v red cable to mechs 12v input
groundī black cable to mechīs black ground

You definitely risk your mainboard's health too !

[Perihelion]

A zap means damage I fear !
Maybe only the diode died, but disconnect the coin signal line immediately from your Ipac ! If 12V flows into the port, the Ipac will be damaged severely either !

luckily i hadnt connected it to the ipac when i did that
only wanted to see, if the coin mech would operate if the ground is down to 5v,
but that was a bad idea, because obviuosly something went wrong.

however mainboard, all of the pc and the coin mech are still working fine.
i will power the coin mech through a molex though .-)

sadly i dont know if i damaged the diode :/

and im still  a little puzzled about the ground connections

[Perihelion]

Just push the 2 ends of the diode into the terminals of the mech.

Sounds like the damage may already be done though

the mech doesnt have a terminal,
theres a connector cable plug with cables as listed.

[Titchgamer]

In that case chop into the cable and joint.

[Ginsonic]

luckily i hadnt connected it to the ipac when i did that

Good choice

sadly i dont know if i damaged the diode :/

Buy a new one, they are pretty cheap, I fear it is damaged (zapping noise)

i will power the coin mech through a molex though .-)

Good choice 2 

the mech doesnt have a terminal,
theres a connector cable plug with cables as listed.

Insert a terminal strip between coin mech and cables to IPAC2 and fix the diode there !

[PL1]

sadly i dont know if i damaged the diode :/

Buy a new one, they are pretty cheap, I fear it is damaged (zapping noise)

Most multimeters have a diode check setting.

You can also check to see if the diode regulates the coin mech's 12v output on the coin signal line when the diode is not installed down to 5v when the diode is installed.

the mech doesnt have a terminal,
theres a connector cable plug with cables as listed.

Insert a terminal strip between coin mech and cables to IPAC2 and fix the diode there !

Euro-style terminals are great for this.





Scott

[Perihelion]

alright,

so can i safely hook all ground (including ipac) together, with a connector e.g.
run it through the diode,
connect this (dropped down by now) with the mechīs signal,
run that to the ipacīs signal input and the circuit is closed?

and though all ground are connected nothing goes wrong,
because the current flows towards signal and closes to ground when the currents value is already powered down?

*fingers crossed, hope i understood this*

diodes are dead cheap, sadly the closest electronics store is next town though,
so i brought the diode to the fancy hifi shop next door.
his techies will check it and hopefully drop a working one by tomorrow,
if the one i have is dead.
saved me 1,5hrs drive and about 5€ tickets and i kept working on the cabinet instead.

[Perihelion]

You can also check to see if the diode regulates the coin mech's 12v output on the coin signal line when the diode is not installed down to 5v when the diode is installed.

when i had the diode between aux ground and mechīs ground, it sometimes rejected correct coins, sometimes he passed them,
dont know if that gives away anything

Euro-style terminals are great for this.

i bought some recently and will make use of em, came in handy underneath the control board aswell to position and fix things nicely, since they have little screw holes

i also painted a new connection schematic to clearify things for me, using terminals here aswell
i hope this makes clear my uncertainty about the ground connections


thanks so far

[PL1]

Looks good so far.   

Made a few minor tweaks to clarify.

You can also check to see if the diode regulates the coin mech's 12v output on the coin signal line when the diode is not installed down to 5v when the diode is installed.

when i had the diode between aux ground and mechīs ground, it sometimes rejected correct coins, sometimes he passed them,
dont know if that gives away anything

There are 3 simple tests here to see if your zener is working correctly.

For test #3, you can use your coin comparator setup if you don't have a suitable battery and resistor.
* Disconnect the IPac input wire (protection in case the zener is bad)
* Red lead to the comparator signal wire. (band-end of the diode)
* Black lead to ground. (other end of the diode)

If the meter shows 5v, you can safely connect the IPac.   


Scott

[Perihelion]

it works!!

got the diode back today, it was still intact.
connected everything as described,
didnt change anything in mame or ipac setup.
so coin signal is set to simulate keyboard key 5.
credits usable for both players in the games i tested so far

PL1, Ginsonic, Titchgamer,
thank you all for helping out !



 

[Titchgamer]

Glad you are all up and running

[pbj]

I think I would have gone with an optoisolator in this case, but glad it's working out for you.

[Ginsonic]