Roto-Pool, Roto-Fruit, Rotolite, Electrodart, Bingola, etc.

[youngerap]

I showed this thread to my eldest son, who just happens to be an electrical engineer for one of our beloved utility companies. "See why I don't have any of these electrickery machines?", I asked. This is simply a foreign language to me except that, unlike communicating in a foreign land, shouting does not help. "This Operator Bell chap clearly served his time, Dad. And you are just a big girl". Nice.

[operator bell]

This Operator Bell chap clearly served his time, Dad.

I take that as a huge compliment

[slotsoffun]

I was wondering if I could do away with the electronic type thing, and maybe install a small motor with a cam fitted that turns to ring the bell then provides the power to the payout relay? Just an idea!!! Would look so much more interesting seeing something half mechanical controlling the bell and relay, rather than a solid state type device!
Just trying to thing of any way of doing the same, without these unreliable little bimetal switches!

Otherwise, I'll admit defeat and just ask the question... How do I connect the wires if I just remove both thermal switches, and live without the bell!!!!!

[slotalot]

one reason the bell/delay circuit is there, is to allow you time to look at the light display and see what you have won before the display steps on to the next position as the coin slide operates.
I have in the past managed to rewire the heater coil on the thermal units, but it is a VERY fiddly job to do..

[slotsoffun]

Slotalot, I think I may attempt what you did and fix the thermal thing... I've taken it apart, but just wondered if.. When I wind the thin wire around the bi metal strip does there have to be a certain number of winds? Also is it critical about the thickness of wire I use?

thanks

[slotalot]

Slotalot, I think I may attempt what you did and fix the thermal thing... I've taken it apart, but just wondered if.. When I wind the thin wire around the bi metal strip does there have to be a certain number of winds? Also is it critical about the thickness of wire I use?

thanks

What you need is Nichrome resistance wire and some heat proof tape for insulation, I cant remember the wire size of hand, just that it was as fine as a human hair..
I will have a look in the workshop tomorrow as I know I had some left over whether I can find it is an other story..

[slotalot]

OK, I have managed to find some nichrome wire & heatproof tape that should do the job,
Next question ? Are you going to Coventry ??

[operator bell]

slotalot, do you happen to know what wire gauge (thickness) your nichrome is? When these coils are switched into circuit they get 40-50 volts across them, so they need a respectable resistance, probably at least 1000 ohms. I have no idea what the resistance of the original coil was - perhaps somebody with an intact device could measure one, though you'd have to disconnect it from the circuit to measure it. Here's a table of resistance per foot for various gauges of nichrome -

If your wire thickness isn't in the table you can work it out - the resistance per foot doubles every three AWG numbers. So for 48AWG for example, go back by threes until you hit the table - 39AWG is three steps of 3 - then take that resistance and go forward again by threes doubling the resistance at each step. It's about 425 ohms/foot. I take it the wire is bare, not varnished, so the turns must not touch or they'll short out.

[slotalot]

slotalot, do you happen to know what wire gauge (thickness) your nichrome is? When these coils are switched into circuit they get 40-50 volts across them, so they need a respectable resistance, probably at least 1000 ohms. I have no idea what the resistance of the original coil was - perhaps somebody with an intact device could measure one, though you'd have to disconnect it from the circuit to measure it.

This why these "overload" units fail so fast, they were only ever made to run on 12 volts, they were designed as indicator flashers for cars, the resistance of these units is only 43 ohms when cold,
the wire I have is 42 SWG nichrome, it is not covered with any thing, and is a sod to wind without shorting the coils out, and you need a steady hand, patience and good eye sight all of which are failing in my case..

[slotsoffun]

After taking apart the thermal switch, I've decided to put it on hold for the moment. These things are so fiddly, what with my sausage like fingers and eyes refusing to focus close up now I'm in my 50s!!!
However, I picked up a cabinet without bits inside for free, and turns out the components I have are from a Roto-Fruit, but looks the same as the Roto Pool. Have started placing parts inside. Will post a picture once completed.
The machine works perfect, bell rings and pays out correctly.
Thanks for all help received from here.

[operator bell]

Good information on the flasher things, now we have it for future reference.

If your wire is 42 gauge it's about 110 ohms a foot. If you can even get a foot of it wound on that tiny thing without the turns shorting, which I doubt, it would draw about 1/3 amp and burn 18 watts. The original at 43 ohms would have pulled a reasonable 3.4 watts on 12V, but more like 50 watts in this circuit. It would take about 4 inches of wire to make 43 ohms.

<edit> all of the above is wrong, since your wire is 42 SWG. That's 38 AWG, and just for fun, 36 BWG for those of you who live in Birmingham. FWIW, they all agree that it's 0.1 millimeters.

[garythegolfer]

Hi again,

In case it helps, I have just posted my electrodart schematics in the resources section:

Electrodart Main Schematic (my Rev C)

These owe much to the earlier efforts of "Slotalot" and "Operator Bell".

I will update them if/when I find any errors. I am about half way through completely rewiring it. If/when I (ever) get this thing working, I will post more info/photos.

Hope it helps

[garythegolfer]

Finally, success: my Electrodart is now working (took just 53 years).

I have just posted my (final?) Rev E schematics and updated "manual" in the RESOURCES section:
Electrodart Main Schematic (my Rev E)

This work was based on the earlier excellent work of Slotalot and OperatorBell.

This should help anyone trying to fix their Electrodart.

GaryTheGolfer

[oneswitch500]

Fantastic resources here, thank you.

I've picked up a sold-as-not working Rotodart fairly recently, and have had some time to work on it. I was worried it was missing some parts as it only has four relays under the two black uni-selectors. Picture here: https://www.dropbox.com/s/43klrt0ssra4m ... 7.jpg?dl=0

After fitting a plug, fuse, remounting the transformer and soldering a loose wire to the rectifier, it came alive. A bit of fiddling got it coining up. Replacing some bulbs, and fiddling a bit with the four relays got it playing. When you win though, the bell jams on, and I have to unplug it, or release one of the contacts on the right-most relay (I think it's a relay).

It never goes into the process of spitting out coins, although the solenoid will kick out coins if I manually activate the contact points that trigger it. I've got a few questions....

1. Would the four relay version suggest one of the last built? Mine is numbered 500 ish off the top of my head.
2. The bulbs are a bit dim. Would using Deoxit or something like it on the left-most uni-selector help brighten things up?
3. What oil would people recommend to lubricate an Electrodart unit, and where would you (I guess all the moving metal parts)?
4. Would I be right in suspecting the timer-related component that works with heat, as to why the pay-out sequence is not being activated?

Huge thanks, and sorry if I'm asking questions that have already been answered.

Barrie

[operator bell]

The original circuit could be simplified. It is possible that they cut out the start relay and run relay on this model. The sticking bell is, yes, a failure of one of the thermal timers that needs to open to step the payout. But wait! It may not be the thermal relay. It could be insufficient voltage. Those old selenium rectifiers have a lifetime, and yours will be about forty years past its sell-by date. If you can, measure the voltage across that capacitor in the clip. It should be more than 40 volts.

A fifty year old electrolytic capacitor is way past its normal lifetime and needs to be replaced anyway. Replace the capacitor with one the same capacitance or more, not less than 63 volts, and replace the selenium rectifier with a silicon bridge rectifier, 5 amps or more, 200 volts or more. I know, it's not original any more, but it may be working, which is better.

I hope you treated the woodworm.

[oneswitch500]

Many thanks for your knowledgeable reply. I'll look into everything you mentioned. I didn't treat the woodworm, I (perhaps hopefully/naively) assumed it was old and long dead. I'll look into that too.

I'm keen to have the thing working over it being completely original. I might look at using the shell of the old capacitor, but I'm guessing there's quite a few of these out there, and mine's unlikely to be one of the best.

Cheers,

Barrie

[oneswitch500]

Couple more questions if you don't mind...

1. What do you think of these as replacement capacitors?

Either....
http://www.mouser.co.uk/ProductDetail/V ... 7xtA%3d%3d or
http://www.mouser.co.uk/ProductDetail/V ... 3f6KYK8%3d (250volts)

Aluminium Electrolytic Capacitors - Leaded 50uF 100volts

TVA_SPL.jpg (4.32 KiB) Viewed 8525 times

...to replace the large capacitor in the machine (marked Radiospares 50mfd - 50v.peak dry electrolytic British made capacitor).

And for the small capacitor connected to the array of four relays on my machine (marked 2uF 150v)....

http://www.mouser.co.uk/ProductDetail/V ... I8RKauE%3d

Aluminium Electrolytic Capacitors - Leaded 150V 2uF

Vishay_TE.jpg (2.97 KiB) Viewed 8523 times

2. Bridge rectifier replacement:

I'm not quite sure how to go about this. I've replaced one on a Pinball machine (like for like), but looking on YouTube and hunting around, I'm still a bit in the dark as to how to proceed. Any extra guidance/pointers on this would be hugely appreciated. Meanwhile, I'll look into the wood-worm and Yale locks which need keys.

Thanks again.

[operator bell]

50 microfarads, that ain't much. 250V, huh. That was a common electrolytic capacitor in the days of valve radios, which is when the game was made, so I guess they took what was laying around. The ripple will be horrid. I answered your PM and recommended 1000 microfarads. You will find modern capacitors are tiny compared to the 1950's version so you can probably go to 2000uF or more to get the same case size. Big is good here.

The voltage on a capacitor changes by (milliseconds)(milliamps) per (microfarad). 50 cycle mains is 10 milliseconds per half cycle, the current drawn by a uniselector at 50 volts is about 200 milliamps, so the voltage drop will be 50*200/50 or 200 volts. Since you only have 50V to start with, that 50uF capacitor may as well not be there, though it may help stop the relays buzzing when the machine is idle.

[oneswitch500]

Had a little time to sit down with my Electrodart again. I've treated the woodworm, replaced the locks and renewed the capacitors and rectifier.

I'm getting 36 volts DC across the large capacitor (70 volts AC). Can't say that this doesn't slightly confuse me. However, the game is running bright and keenly apart from two main issues.

1. The bell stays ringing constantly on on a winning number, and the pay-out will not initiate (the machine will kick out three coins at a time if I press the actuator on the right-most relay assembly and step the numbers onwards one at a time normally - this is the only way to stop the bell ringing and locking up - including turning it off and on).

2. The thermal cut-out for holding the push-button too long doesn't work. Not too worried about this, unless it's a safety concern.


For the left-most thermal overload component...

A=Grey
B=Pink
C=Green (this wire nearest to me, is directly connected to the orange bell wire that I disconnected).

Green and Pink are normally closed.

Measuring across B and C gives me 00.2 to 00.4 on my multimeter (set to 200 Ohms). That seems far too low. If I measure across A and C I get strange behaviour. Sometimes quite high, sometimes nothing. Nothing like 40 Ohms though. Should I be doing this with the power off or on?

Any help hugely appreciated, as before.

Barrie

[operator bell]

Ok, let's try and clear up the confusion.

The difference between 36V DC and 70V AC can only be explained by a measurement error - the 70V is wrong. 36V would be just right if the transformer is 24V AC, which it probably is.

The delay heater coil is in parallel with the bell. The low resistance between B and C is because you're measuring a closed contact. The coil resistance can be measured between A and B, or A and C, but for one of those - probably C - the connection goes through the break contact, and pushing the probe on the terminal may disturb it and change the reading. I take it you disconnected the bell before you measured, else you're measuring the bell in parallel. Any resistance measurement through the delay heater is good, it shows it's not burned out.

You can't take resistance measurements with the power on!

When you hit a winner the circuit is closed to energize the bell and the thermal delay. The payout relay is shorted out by the delay contact and does not operate. When the delay heats up and opens, current flows through the coin slide home contact, the payout relay and the bell, though the current should not be enough for the bell and the delay to keep running. The payout relay latches itself on and sends power to the coin slide and the left uniselector, which pulls in but doesn't step yet. The coin slide moves and opens its home contact, but the payout relay is now latched on by its own contact. When the coil slide drops the coin it opens its end of stroke switch, which drops out the payout relay. The coin slide then drops back, and the left uniselector steps. If that was a 2 coin payout, it steps off the payout circuit and we're done, otherwise ... By this time the thermal delay may or may not have closed its contact again. If it has, the same cycle repeats. If not, as soon as the coin slide hits the home contact it re-energizes the payout relay for another step. UNTIL the left uniselector steps off the payout circuit.

The point here is that the thermal delay has one job, which is to delay long enough for the bell to sound and attract attention. You can remove it from circuit (but leave the bell in) and the mechanical delay of the coin slide going back and forth will accomplish the payout.