EM switch types

[CDB]

Hi All,

Please help me by explaining why my Bally EM has different switch (points) types.  Most of the switches are of the dome type in the mechanism and handle release, but the upper feature unit that steps for multiple coin entry has the flat points on the relay.  I have had tons of trouble adjusting the flat feature points on the relay to prevent multiple stepping when a single coin in signaled. If I were to change out the flat points for the dome type would this eliminate the double stepping and point sticking issues. The flat points have been cleaned and repeatedly adjusted with little avail. Could the flat points be for the purpose for a quick contact while the dome type is for a more continuous connection? I would like to change out the flats with the domes, but I wanted some input here before I warm up my soldering iron. Any input with my point problem(s) would be greatly appreciated.

Happy New Year!

CDB

[Op-Bell]

The flat points are for high current contacts, for large solenoids like step-up coils. You really should replace like with like, as the dome contacts may burn out quickly. The flats are usually some hard metal like tungsten, while the domes are silver or silver-on-brass. Multiple stepping is probably due to the contacts bouncing and arcing. The flats should be parallel and meet flush, with good spring pressure holding them together. The contact springs should be straight, not curved or kinked, and only the fixed spring should be tweaked to adjust, never the moving spring. Usually there's a stiffening leaf alongside the fixed spring, which should be laying up against the contact spring to give it some extra stiffness when the contacts are closed.

[CDB]

 

Thanks for the information on the purpose of the different types of points. I still have double stepping problems after tweaking the contacts many times. Could the points be so worn and pitted that they are sticking?  If so, do you know of a source for their replacement(s)? I read that contact cleaner is not to be used at all and some blackening is OK.

I appreciate your expertese,

CDB

[Op-Bell]

It may not be the contact you think it is.There may be an end-of-stroke contact, or one that breaks the circuit after some number of steps. That may be the contact that's shaking and bouncing.

[CDB]

The end of stroke contact definitely affects the switch operation. I (embarrassingly) discovered that the 2 switch block screws have worked a little loose.  After tightening them, the multiple stepping and sticking has improved, but not completely.  Should I apply some thread lock on the threads to prevent future loosening? Also, there are no spring stiffening leafs backing up the fixed contact springs. Do you have a suggestion for making them. I was thinking of using a little piece of foam for this, but it probably will soon deteriorate over time.
Thanks again,

CDB

[CDB]

Another question,

The large resistor over the contact switches in this feature stepper gets very hot. It is way too hot to touch. Is this normal? Perhaps this is causing some grief too.  I believe it is 1K ohm.

CDB

[Op-Bell]

There are large resistors here and there across various coils in a Bally EM. The purpose is to keep the coil energized during momentary breaks in the current, like on stepping switches that run over banks of studs. It also stops whatever contact is supplying the coil from arcing - the win relay usually has a big resistor for these reasons. The resistor will get very hot quite quickly when the coil is pulled in, but this is nothing to worry about unless a contact gets stuck and holds it in for an excessive time. If it's 1k, and has 50 volts across it, the continuous power dissipation would be V^2/R, two and a half watts, but normally it's not continuous.

[CDB]

Hi All,

The problem of double stepping  with the feature stepper was finally resolved with the replacement of the little spring on the "G" coil that pulls the points back into normal (open) position.
We had no idea that this spring would weaked over decades of time. .

CDB

[StatFreak]

Hey CDB, Not to hijack this thread, but what casino is your avatar from? It looks somewhat like the old Harrah's Genie, but not.

[CDB]

Mr. Stat Freak,

You are correct in your thinking!  That is the Harrah's Genie. I found an old faded image from an all chrome Pace machine, scanned it and touched it up using the paint program on this old computer. It is quiet easy to do too!  I have duplicated several really faded awards cards and printed them out on bumper sticker plasticized paper which is available at Office Max.    With some time and effort one can produce amazingly close to original images. 
CDB

[StatFreak]

Mr. Stat Freak,

You are correct in your thinking!  That is the Harrah's Genie. I found an old faded image from an all chrome Pace machine, scanned it and touched it up using the paint program on this old computer. It is quiet easy to do too!  I have duplicated several really faded awards cards and printed them out on bumper sticker plasticized paper which is available at Office Max.    With some time and effort one can produce amazingly close to original images. 
CDB

Very cool!  I gave you a K+


Stat

[frenchmarky]

If you are referring to the tiny springs that pull the relay armature back to it's at-rest position, I had to really check those out good on my 873.  Lots of different springs were on the relays, figure that they end up popping off or getting knocked off during servicing and get lost, and the replacements might not be the exact correct ones.  Important to adjust all the moving switch blades in the relay(s) also, cuz if they are tweaking too hard on the armature eventually the armature spring can't pull hard enough to return the armature fully.

As for flat vs. round points, the Bally relays usually have a round point + flat point so that the round one works a good seat into the flat one.  The big units like the feature unit have flatter ones that match the size of the flat button contacts.  The payout counter uses the more highly rounded points.  Those ride on flat traces, and the much finer steps this unit takes requires a tinier contact point so you don't get shorts across traces etc.