Nonsense From Sigma 50-B Slot Machine Board

[StudentSlotFixer]

I am trying to fix this slot machine to make it a student film prop. I bought it from Facebook and was told it worked 3 months ago. I've tried resetting it multiple times, Switching out the power source,  cleaning it, replacing the 3 volt coin battery, and shorting components on the board. So far I have been able to get it to a back end menu which allowed me to figure out that everything in it is operation. The only issue is the board keeps sending out nonsense which has made it so I have never gotten the coin reader to accept the coin and the motors to spin the wheels. Does anyone have any idea what I can try next?

[Stayouttadabunker]

Return it? jk 
I have no idea what is wrong with it. 

Can you post a clear photo of the display panel and what numbers are showing on it? 
Maybe that'll help in troubleshooting.

[StudentSlotFixer]

I have it in my studio so I don't have a photo at the moment but I can post one later. The screen showed two 0 0 and a glitched "-". The "insert coin" is also flashing. This is the state the machine is in normally. Occasionally when I reset it a bunch I get to the moderator screen that lets me turn the bill reader on and off along with some other options I don't remember. In this menu there is also a section that shows "00000000" which let me know that everything on the screen is functional. Sometimes when I reset it I get some error resembling this "%$^#&$**@$*". I will also add that the coin comparator light is on and sometimes moves and the wheels turn every now and then which lets me know that a current is getting to them.

[Chris-socal]

SG series needs very little to reset, however there are some inherent problems that can come up.
Those LED readouts can indicate problems with the 5v rail.

I have worked on several of these but it probably won’t be a straightforward fix, Im going to need some information and pictures and talk through specifics.

Are you getting any sounds?

Did you mess with any of the jumpers?

For me to best help It would be helpful to see a clear picture of the game board out of the machine from above. When you replace the board be absolutely sure you have the power supply pins lined up correctly….its the white connector on the back right. Its easy to get it off one pin left or right.

Lastly, does your game have one or three power supplies?  If you have 3 they are usually mounted on the ceiling of the inner cabinet. If you ave one its probably mounted on the back wall.

Chris

[StudentSlotFixer]

Hi Chris

We were getting some sounds occasionally, usually the speaker is outputting static though with occasional very muted ticks,

We didn't mess with any of the jumpers

Power supply connector is lined up

Only one power supply mounted on the back wall

Let me know if there is any other information I can send you.

[Chris-socal]

Ok on a Sigma machine you absolutely must test the 3 power rails, there are 3.
5v runs the computer
12v runs accessories
24v runs the reels

Sigma machines are synonymous with power supply problems. I have a video on YouTube on how to bench test them. You will need a multi -meter.

You can initially test the voltages in the machine by probing that power supply connector but be careful not to let your probes short on anything, its a tight fit getting back in there. You can test it with the board removed. There are three ground wires, one for each rail then two brown for 24v, two red for 5v and one or two yellow for 12v. What tends to happen on these is the 5v drifts. It might start up at 4.7 v and the computer doesn’t like it. Then it ramps up and hits the 5v range and it boots but many times it doesn’t put out enough current to run the board and it starts glitching. Thats why you need to pull the power supply and bench test it under load.

I can almost guarantee you the. 5v rail is at least drifting.

Please post a pic of the board when you have time.

Chris

[StudentSlotFixer]

Here are some photos of the board. I will try that out and get back to you on how that goes.

[StudentSlotFixer]

We swapped in a computer power supply and got mixed results. It unlocked more features and consistently showed us "Ram Wrong" and when we cleared RAM it would go back to the "0, 0" with a glitched "-". The jumpers used to put in the computer supply could have limited the amount of current it could draw at start up. On the sony 4 series it was dropping to 4.9v. Our next idea is trying a bench power supply to make sure it's getting the right amount of power. Any other idea or experience would be appreciated.

[Chris-socal]

Rams wrong is a good thing. Usually you turn the reset key and it resets the reels and engages the coin mech. If you have a Bill Validator you might have to activate it. All covered in the manual.

To remove the board you just flip the side levers of each connector open and lift the connector up. I don’t think there are any two the same so you can’t really put them back in the wrong slot.

You need to check the voltage of the backup battery. Those typically come with a backup capacitor…1Farad 4.5v or 5v. Either is fine. The machine needs to be left on for awhile to charge it, if its dead it will boot to Rams wrong every time.

A PC power supply is fine for the 5 and 12v but the reels need 24v and it is highly likely that rail is bad too. So highly likely that I don’t test anything else on SGs until I have pulled the PS and checked. They use these capacitors that leak and corrode the board.

Chris

[Badbaud]

The 1 Farad capacitor is a Super Cap and is used instead of a physical battery.
You can use a standard 3.6V LiIon battery in place of the Super Cap
but from what I can see from the pictures the replacement battery used
is not soldered in properly, hence the RAM error.